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exist. Unlike cranial tumors, the majority of spinal tumors are histologically benign. Under-standing two major spinal concepts—stability and neural com-pression—facilitates an understanding of the effects of spinal tumors. Destruction of bones or ligaments can cause spinal instability, leading to deformities such as compression, kyphosis, subluxation, all of which harbor the potential for subsequent neural compression. Tumor growth in the spinal canal or neu-ral foramina can cause direct compression of the spinal cord or nerve roots and cause pain and loss of function. Classically, the pain is worse at night. Anatomic categorization provides the most logical approach to these tumors. Certain tumors present in characteristic locations. An understanding of the anatomy leads to an understanding of the clinical presentation and possible therapeutic options.Extradural Tumors. Extradural tumors account for approxi-mately 55% of spinal tumors. This category includes tumors Figure
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Surgery_Schwartz. exist. Unlike cranial tumors, the majority of spinal tumors are histologically benign. Under-standing two major spinal concepts—stability and neural com-pression—facilitates an understanding of the effects of spinal tumors. Destruction of bones or ligaments can cause spinal instability, leading to deformities such as compression, kyphosis, subluxation, all of which harbor the potential for subsequent neural compression. Tumor growth in the spinal canal or neu-ral foramina can cause direct compression of the spinal cord or nerve roots and cause pain and loss of function. Classically, the pain is worse at night. Anatomic categorization provides the most logical approach to these tumors. Certain tumors present in characteristic locations. An understanding of the anatomy leads to an understanding of the clinical presentation and possible therapeutic options.Extradural Tumors. Extradural tumors account for approxi-mately 55% of spinal tumors. This category includes tumors Figure
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Surgery_Schwartz_12303
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understanding of the clinical presentation and possible therapeutic options.Extradural Tumors. Extradural tumors account for approxi-mately 55% of spinal tumors. This category includes tumors Figure 42-24. Postcontrast T1-weighted sagittal magnetic reso-nance imaging demonstrating a large sellar/suprasellar lesion (arrowheads) involving the third ventricle superiorly and abut-ting the midbrain and pons posteriorly. The patient presented with progressive visual field and acuity loss. Pathology and lab work revealed a nonfunctioning pituitary adenoma.Figure 42-25. Postcontrast T1-weighted axial magnetic resonance imaging demonstrating a nonenhancing mass in the left cerebello-pontine angle with brain stem compression. White arrowhead indi-cates interface of tumor and brain stem. Black arrowhead indicates deformed fourth ventricle. Pathology revealed epidermoid tumor.Brunicardi_Ch42_p1827-p1878.indd 185901/03/19 7:17 PM 1860SPECIFIC CONSIDERATIONSPART IIarising within the bony
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Surgery_Schwartz. understanding of the clinical presentation and possible therapeutic options.Extradural Tumors. Extradural tumors account for approxi-mately 55% of spinal tumors. This category includes tumors Figure 42-24. Postcontrast T1-weighted sagittal magnetic reso-nance imaging demonstrating a large sellar/suprasellar lesion (arrowheads) involving the third ventricle superiorly and abut-ting the midbrain and pons posteriorly. The patient presented with progressive visual field and acuity loss. Pathology and lab work revealed a nonfunctioning pituitary adenoma.Figure 42-25. Postcontrast T1-weighted axial magnetic resonance imaging demonstrating a nonenhancing mass in the left cerebello-pontine angle with brain stem compression. White arrowhead indi-cates interface of tumor and brain stem. Black arrowhead indicates deformed fourth ventricle. Pathology revealed epidermoid tumor.Brunicardi_Ch42_p1827-p1878.indd 185901/03/19 7:17 PM 1860SPECIFIC CONSIDERATIONSPART IIarising within the bony
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Surgery_Schwartz_12304
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Surgery_Schwartz
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arrowhead indicates deformed fourth ventricle. Pathology revealed epidermoid tumor.Brunicardi_Ch42_p1827-p1878.indd 185901/03/19 7:17 PM 1860SPECIFIC CONSIDERATIONSPART IIarising within the bony vertebral structures and from within the epidural space. Destruction of the bone can lead to instability and fractures, causing pain and/or deformity. Epidural expan-sion can lead to spinal cord or nerve root compression with myelopathy, radiculopathy, or a combination thereof.Metastatic Tumors Metastatic tumors are the most common extradural tumors. Spinal metastases most commonly occur in the thoracic and lumbar vertebral bodies because the greatest volume of red bone marrow is found in these regions. The most common primary sources of spine metastasis are lymphoma, lung, breast, and prostate. Other sources include renal, colon, thyroid, sarcoma, and melanoma. Most spinal metastases create osteolytic lesions. Osteoblastic, sclerotic lesions suggest pros-tate cancer in men and breast
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Surgery_Schwartz. arrowhead indicates deformed fourth ventricle. Pathology revealed epidermoid tumor.Brunicardi_Ch42_p1827-p1878.indd 185901/03/19 7:17 PM 1860SPECIFIC CONSIDERATIONSPART IIarising within the bony vertebral structures and from within the epidural space. Destruction of the bone can lead to instability and fractures, causing pain and/or deformity. Epidural expan-sion can lead to spinal cord or nerve root compression with myelopathy, radiculopathy, or a combination thereof.Metastatic Tumors Metastatic tumors are the most common extradural tumors. Spinal metastases most commonly occur in the thoracic and lumbar vertebral bodies because the greatest volume of red bone marrow is found in these regions. The most common primary sources of spine metastasis are lymphoma, lung, breast, and prostate. Other sources include renal, colon, thyroid, sarcoma, and melanoma. Most spinal metastases create osteolytic lesions. Osteoblastic, sclerotic lesions suggest pros-tate cancer in men and breast
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Surgery_Schwartz_12305
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Other sources include renal, colon, thyroid, sarcoma, and melanoma. Most spinal metastases create osteolytic lesions. Osteoblastic, sclerotic lesions suggest pros-tate cancer in men and breast cancer in women.Patients with progressive neurologic dysfunction due to a metastatic lesion should undergo urgent surgery followed by radiation therapy.70 Patients with debilitating pain may undergo radiation therapy with close observation for neurologic deterio-ration. Preoperative neurologic function correlates with postop-erative function. Patients may lose function over hours. These patients should be given high-dose IV dexamethasone, taken immediately to MRI, and then to the OR or radiation therapy suite. Indications for surgery include failure of radiation ther-apy, spinal instability, recurrence after radiation therapy, and the need for diagnosis in cases of unknown primary tumors. Most cases with significant bone involvement require both decom-pression and fusion. Bony fusion usually
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Surgery_Schwartz. Other sources include renal, colon, thyroid, sarcoma, and melanoma. Most spinal metastases create osteolytic lesions. Osteoblastic, sclerotic lesions suggest pros-tate cancer in men and breast cancer in women.Patients with progressive neurologic dysfunction due to a metastatic lesion should undergo urgent surgery followed by radiation therapy.70 Patients with debilitating pain may undergo radiation therapy with close observation for neurologic deterio-ration. Preoperative neurologic function correlates with postop-erative function. Patients may lose function over hours. These patients should be given high-dose IV dexamethasone, taken immediately to MRI, and then to the OR or radiation therapy suite. Indications for surgery include failure of radiation ther-apy, spinal instability, recurrence after radiation therapy, and the need for diagnosis in cases of unknown primary tumors. Most cases with significant bone involvement require both decom-pression and fusion. Bony fusion usually
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Surgery_Schwartz_12306
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after radiation therapy, and the need for diagnosis in cases of unknown primary tumors. Most cases with significant bone involvement require both decom-pression and fusion. Bony fusion usually takes 2 to 3 months. Prognosis governs operative decisions. Surgery is unlikely to improve quality of life for patients with a life expectancy of 3 months or less, but it is likely to improve quality of life for patients with life expectancy of 6 months or more. Benefit for patients with 3to 6-months’ life expectancy is unclear and requires frank discussion with the patient and family. Patients who are unlikely to tolerate general anesthesia, are already completely paralyzed, or who have very radiosensitive tumors such as multiple myeloma and lymphoma, should not generally undergo surgery.Management Principles of Spinal Cord Compression in Metastatic Cancer of the Spine Spinal cord compression due to tumor burden is important to distinguish because it can, as with any other form of cord
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Surgery_Schwartz. after radiation therapy, and the need for diagnosis in cases of unknown primary tumors. Most cases with significant bone involvement require both decom-pression and fusion. Bony fusion usually takes 2 to 3 months. Prognosis governs operative decisions. Surgery is unlikely to improve quality of life for patients with a life expectancy of 3 months or less, but it is likely to improve quality of life for patients with life expectancy of 6 months or more. Benefit for patients with 3to 6-months’ life expectancy is unclear and requires frank discussion with the patient and family. Patients who are unlikely to tolerate general anesthesia, are already completely paralyzed, or who have very radiosensitive tumors such as multiple myeloma and lymphoma, should not generally undergo surgery.Management Principles of Spinal Cord Compression in Metastatic Cancer of the Spine Spinal cord compression due to tumor burden is important to distinguish because it can, as with any other form of cord
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Surgery_Schwartz_12307
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Principles of Spinal Cord Compression in Metastatic Cancer of the Spine Spinal cord compression due to tumor burden is important to distinguish because it can, as with any other form of cord compression, cause paralysis and loss of bowel and bladder function. A randomized controlled trial demonstrated that patients with spinal cord compression from metastatic tumor have better outcomes with decompres-sive surgery and radiotherapy compared to radiotherapy alone.70 Patients with radiosensitive tumors, such as multiple myeloma and lymphoma, are excluded from this group. Another impor-tant tool in assessing these patients is the SINS (Spinal Instabil-ity Neoplastic Score). This scale grades the utility of operative intervention in metastatic cancer to the spine on the basis of pain, deformity, location, type of bone lesion, integrity of verte-bral body, and posterior element involvement.71Primary Tumors Hemangiomas are benign tumors found in 10% of people at autopsy. They occur in the
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Surgery_Schwartz. Principles of Spinal Cord Compression in Metastatic Cancer of the Spine Spinal cord compression due to tumor burden is important to distinguish because it can, as with any other form of cord compression, cause paralysis and loss of bowel and bladder function. A randomized controlled trial demonstrated that patients with spinal cord compression from metastatic tumor have better outcomes with decompres-sive surgery and radiotherapy compared to radiotherapy alone.70 Patients with radiosensitive tumors, such as multiple myeloma and lymphoma, are excluded from this group. Another impor-tant tool in assessing these patients is the SINS (Spinal Instabil-ity Neoplastic Score). This scale grades the utility of operative intervention in metastatic cancer to the spine on the basis of pain, deformity, location, type of bone lesion, integrity of verte-bral body, and posterior element involvement.71Primary Tumors Hemangiomas are benign tumors found in 10% of people at autopsy. They occur in the
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Surgery_Schwartz_12308
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location, type of bone lesion, integrity of verte-bral body, and posterior element involvement.71Primary Tumors Hemangiomas are benign tumors found in 10% of people at autopsy. They occur in the vertebral bodies of the thoracolumbar spine and are frequently asymptomatic. They are often vascular and may hemorrhage, causing pain or neurologic deficit. Large hemangiomas can destabilize the spine and predispose to fracture. Osteoblastic lesions include osteoid osteoma and osteoblastoma. The latter tends to be larger and more destructive. Aneurysmal bone cysts are nonneoplastic, expansile, lytic lesions containing thin-walled blood cavities that usually occur in the lamina or spinous processes of the cer-vicothoracic spine. They may cause pain or sufficiently weaken the bone to cause a fracture. Cancers arising primarily in the bony spine include Ewing’s sarcoma, osteosarcoma, chondro-sarcoma, and plasmacytoma.Intradural Extramedullary Tumors Intradural extramed-ullary tumors constitute
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Surgery_Schwartz. location, type of bone lesion, integrity of verte-bral body, and posterior element involvement.71Primary Tumors Hemangiomas are benign tumors found in 10% of people at autopsy. They occur in the vertebral bodies of the thoracolumbar spine and are frequently asymptomatic. They are often vascular and may hemorrhage, causing pain or neurologic deficit. Large hemangiomas can destabilize the spine and predispose to fracture. Osteoblastic lesions include osteoid osteoma and osteoblastoma. The latter tends to be larger and more destructive. Aneurysmal bone cysts are nonneoplastic, expansile, lytic lesions containing thin-walled blood cavities that usually occur in the lamina or spinous processes of the cer-vicothoracic spine. They may cause pain or sufficiently weaken the bone to cause a fracture. Cancers arising primarily in the bony spine include Ewing’s sarcoma, osteosarcoma, chondro-sarcoma, and plasmacytoma.Intradural Extramedullary Tumors Intradural extramed-ullary tumors constitute
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Surgery_Schwartz_12309
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Cancers arising primarily in the bony spine include Ewing’s sarcoma, osteosarcoma, chondro-sarcoma, and plasmacytoma.Intradural Extramedullary Tumors Intradural extramed-ullary tumors constitute approximately 40% of spinal tumors and arise from the meninges or nerve root elements. They may compress the spinal cord, causing myelopathy, or the nerve roots, causing radiculopathy. The most common intradural extramedullary tumors are typically benign, slow growing, and well circumscribed. Rare benign epidural masses include arach-noid cysts, dermoids, and epidermoids. Rare malignant epidural tumors include metastases and high-grade gliomas, or “drop” metastases from posterior fossa gliomas.Meningioma Meningiomas arise from the arachnoidea mater. They appear to be dural based and enhance on MRI. An enhanc-ing “dural tail” may be seen. They occur most commonly in the thoracic spine (Fig. 42-26) but also arise in the cervical and lumbar regions. Some spinal meningiomas grow into the Figure
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Surgery_Schwartz. Cancers arising primarily in the bony spine include Ewing’s sarcoma, osteosarcoma, chondro-sarcoma, and plasmacytoma.Intradural Extramedullary Tumors Intradural extramed-ullary tumors constitute approximately 40% of spinal tumors and arise from the meninges or nerve root elements. They may compress the spinal cord, causing myelopathy, or the nerve roots, causing radiculopathy. The most common intradural extramedullary tumors are typically benign, slow growing, and well circumscribed. Rare benign epidural masses include arach-noid cysts, dermoids, and epidermoids. Rare malignant epidural tumors include metastases and high-grade gliomas, or “drop” metastases from posterior fossa gliomas.Meningioma Meningiomas arise from the arachnoidea mater. They appear to be dural based and enhance on MRI. An enhanc-ing “dural tail” may be seen. They occur most commonly in the thoracic spine (Fig. 42-26) but also arise in the cervical and lumbar regions. Some spinal meningiomas grow into the Figure
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Surgery_Schwartz_12310
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An enhanc-ing “dural tail” may be seen. They occur most commonly in the thoracic spine (Fig. 42-26) but also arise in the cervical and lumbar regions. Some spinal meningiomas grow into the Figure 42-26. T2-weighted sagittal magnetic resonance imaging of the midthoracic spine demonstrating a well-encapsulated tumor arising from the dura posteriorly and compressing the spinal cord. Arrowhead points to dorsal location of the mass. The patient pre-sented with worsening gait and lower extremity spasticity. Pathol-ogy demonstrated meningioma.Brunicardi_Ch42_p1827-p1878.indd 186001/03/19 7:17 PM 1861NEUROSURGERYCHAPTER 42epidural space. Growth causes cord compression and progres-sive myelopathy with hyperreflexia, spasticity, and gait difficul-ties. Surgical excision is the treatment of choice. The surgeon often finds a clean margin between the tumor, dura, and spinal cord, allowing en bloc resection without damage to the cord.Schwannoma Schwannomas are derived from peripheral nerve
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Surgery_Schwartz. An enhanc-ing “dural tail” may be seen. They occur most commonly in the thoracic spine (Fig. 42-26) but also arise in the cervical and lumbar regions. Some spinal meningiomas grow into the Figure 42-26. T2-weighted sagittal magnetic resonance imaging of the midthoracic spine demonstrating a well-encapsulated tumor arising from the dura posteriorly and compressing the spinal cord. Arrowhead points to dorsal location of the mass. The patient pre-sented with worsening gait and lower extremity spasticity. Pathol-ogy demonstrated meningioma.Brunicardi_Ch42_p1827-p1878.indd 186001/03/19 7:17 PM 1861NEUROSURGERYCHAPTER 42epidural space. Growth causes cord compression and progres-sive myelopathy with hyperreflexia, spasticity, and gait difficul-ties. Surgical excision is the treatment of choice. The surgeon often finds a clean margin between the tumor, dura, and spinal cord, allowing en bloc resection without damage to the cord.Schwannoma Schwannomas are derived from peripheral nerve
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Surgery_Schwartz_12311
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choice. The surgeon often finds a clean margin between the tumor, dura, and spinal cord, allowing en bloc resection without damage to the cord.Schwannoma Schwannomas are derived from peripheral nerve sheath Schwann cells. They are benign, encapsulated tumors that rarely undergo malignant degeneration. While two-thirds are entirely intradural, one-sixth are entirely extradural, and one-sixth have a classic “dumbbell” shape from intradural and extra-dural components. Symptoms result from radiculopathy, often presenting as pain or myelopathy. Symptomatic lesions should be surgically resected. The parent nerve root usually can be pre-served. Patients with multiple schwannomas likely have NF2. In these patients, a careful neurologic examination is needed to determine which lesions are symptomatic and require resection.Neurofibroma In contrast to schwannomas, neurofibromas tend to appear more fusiform and to grow within the parent nerve, rather than forming an encapsulated mass branching
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Surgery_Schwartz. choice. The surgeon often finds a clean margin between the tumor, dura, and spinal cord, allowing en bloc resection without damage to the cord.Schwannoma Schwannomas are derived from peripheral nerve sheath Schwann cells. They are benign, encapsulated tumors that rarely undergo malignant degeneration. While two-thirds are entirely intradural, one-sixth are entirely extradural, and one-sixth have a classic “dumbbell” shape from intradural and extra-dural components. Symptoms result from radiculopathy, often presenting as pain or myelopathy. Symptomatic lesions should be surgically resected. The parent nerve root usually can be pre-served. Patients with multiple schwannomas likely have NF2. In these patients, a careful neurologic examination is needed to determine which lesions are symptomatic and require resection.Neurofibroma In contrast to schwannomas, neurofibromas tend to appear more fusiform and to grow within the parent nerve, rather than forming an encapsulated mass branching
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Surgery_Schwartz_12312
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and require resection.Neurofibroma In contrast to schwannomas, neurofibromas tend to appear more fusiform and to grow within the parent nerve, rather than forming an encapsulated mass branching off the nerve. Neurofibromas are benign but not encapsulated. They present similarly to schwannomas, and the two may be difficult to differentiate on imaging. Salvage of the parent nerve is more challenging with neurofibromas. To improve the likelihood of total resection, thoracic and high cervical nerve roots may be sacrificed with minimal deficit. Patients with multiple neurofi-bromas likely have NF1, also known as von Recklinghausen’s neurofibromatosis. Resection for symptomatic lesions should be offered.Intramedullary Tumors. Intramedullary tumors constitute approximately 5% of spinal tumors. They arise from within the parenchyma of the spinal cord. Common presenting symptoms are local dysesthesia, burning pain, radicular pain, sensory loss, weakness, or sphincter dysfunction. Patients with
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Surgery_Schwartz. and require resection.Neurofibroma In contrast to schwannomas, neurofibromas tend to appear more fusiform and to grow within the parent nerve, rather than forming an encapsulated mass branching off the nerve. Neurofibromas are benign but not encapsulated. They present similarly to schwannomas, and the two may be difficult to differentiate on imaging. Salvage of the parent nerve is more challenging with neurofibromas. To improve the likelihood of total resection, thoracic and high cervical nerve roots may be sacrificed with minimal deficit. Patients with multiple neurofi-bromas likely have NF1, also known as von Recklinghausen’s neurofibromatosis. Resection for symptomatic lesions should be offered.Intramedullary Tumors. Intramedullary tumors constitute approximately 5% of spinal tumors. They arise from within the parenchyma of the spinal cord. Common presenting symptoms are local dysesthesia, burning pain, radicular pain, sensory loss, weakness, or sphincter dysfunction. Patients with
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Surgery_Schwartz_12313
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arise from within the parenchyma of the spinal cord. Common presenting symptoms are local dysesthesia, burning pain, radicular pain, sensory loss, weakness, or sphincter dysfunction. Patients with such symp-toms should undergo MRI of the entire spine with and without enhancement.Ependymoma Ependymomas are the most common intramed-ullary tumors in adults. There are several histologic variants. The myxopapillary type occurs in the conus medullaris or the filum terminale in the lumbar region and has the best progno-sis after resection. The cellular type occurs more frequently in the cervical cord. Many spinal ependymomas have cystic areas and may contain hemorrhage. Surgical removal can improve function. A distinct tumor margin often exists, allowing safer excision. Postoperative radiation therapy after subtotal resection may prolong disease control.Astrocytoma Astrocytomas are the most common intramedul-lary tumors in children, although they also occur in adults. They may occur at all
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Surgery_Schwartz. arise from within the parenchyma of the spinal cord. Common presenting symptoms are local dysesthesia, burning pain, radicular pain, sensory loss, weakness, or sphincter dysfunction. Patients with such symp-toms should undergo MRI of the entire spine with and without enhancement.Ependymoma Ependymomas are the most common intramed-ullary tumors in adults. There are several histologic variants. The myxopapillary type occurs in the conus medullaris or the filum terminale in the lumbar region and has the best progno-sis after resection. The cellular type occurs more frequently in the cervical cord. Many spinal ependymomas have cystic areas and may contain hemorrhage. Surgical removal can improve function. A distinct tumor margin often exists, allowing safer excision. Postoperative radiation therapy after subtotal resection may prolong disease control.Astrocytoma Astrocytomas are the most common intramedul-lary tumors in children, although they also occur in adults. They may occur at all
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Surgery_Schwartz_12314
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therapy after subtotal resection may prolong disease control.Astrocytoma Astrocytomas are the most common intramedul-lary tumors in children, although they also occur in adults. They may occur at all levels, although more often in the cervical cord. The tumor may interfere with the CSF-containing central canal of the spinal cord, leading to a dilated central canal, referred to as syringomyelia (syrinx). Spinal astrocytomas are usually low grade, but complete excision is rarely possible due to the nonencapsulated, infiltrative nature of the tumor. As a result, patients with astrocytomas fare worse overall than patients with ependymomas.Other Tumors. Other types of rare tumors include high-grade astrocytomas, dermoids, epidermoids, teratomas, hemangiomas, hemangioblastomas, and metastases. Patients usually present with pain. Prognosis generally depends on preoperative func-tion and the histologic characteristics of the lesion.Future DirectionsFuture directions in the neurosurgical
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Surgery_Schwartz. therapy after subtotal resection may prolong disease control.Astrocytoma Astrocytomas are the most common intramedul-lary tumors in children, although they also occur in adults. They may occur at all levels, although more often in the cervical cord. The tumor may interfere with the CSF-containing central canal of the spinal cord, leading to a dilated central canal, referred to as syringomyelia (syrinx). Spinal astrocytomas are usually low grade, but complete excision is rarely possible due to the nonencapsulated, infiltrative nature of the tumor. As a result, patients with astrocytomas fare worse overall than patients with ependymomas.Other Tumors. Other types of rare tumors include high-grade astrocytomas, dermoids, epidermoids, teratomas, hemangiomas, hemangioblastomas, and metastases. Patients usually present with pain. Prognosis generally depends on preoperative func-tion and the histologic characteristics of the lesion.Future DirectionsFuture directions in the neurosurgical
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Surgery_Schwartz_12315
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Patients usually present with pain. Prognosis generally depends on preoperative func-tion and the histologic characteristics of the lesion.Future DirectionsFuture directions in the neurosurgical management of brain tumors are related to improved genetic characterization of brain tumors and technological advances. Regarding the former, the recent update of the World Health Organization classification of central nervous system tumors, alluded to earlier in this chap-ter, emphasizes an integrated classification approach utilizing both histologic and molecular characteristics.72 The addition of the latter feature underscores significant advances in the genet-ics of CNS tumors, which are being translated to treatment. Immunotherapy, for example, is an active area of research in the treatment of GBM. In this approach, immune cells such as T cells and dendritic cells are leveraged to target tumor-specific tissue. These approaches will play an important role as adjuvant therapy to
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Surgery_Schwartz. Patients usually present with pain. Prognosis generally depends on preoperative func-tion and the histologic characteristics of the lesion.Future DirectionsFuture directions in the neurosurgical management of brain tumors are related to improved genetic characterization of brain tumors and technological advances. Regarding the former, the recent update of the World Health Organization classification of central nervous system tumors, alluded to earlier in this chap-ter, emphasizes an integrated classification approach utilizing both histologic and molecular characteristics.72 The addition of the latter feature underscores significant advances in the genet-ics of CNS tumors, which are being translated to treatment. Immunotherapy, for example, is an active area of research in the treatment of GBM. In this approach, immune cells such as T cells and dendritic cells are leveraged to target tumor-specific tissue. These approaches will play an important role as adjuvant therapy to
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Surgery_Schwartz_12316
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treatment of GBM. In this approach, immune cells such as T cells and dendritic cells are leveraged to target tumor-specific tissue. These approaches will play an important role as adjuvant therapy to neurosurgical approaches.Recent advances in neurosurgical technology are being used to address previous operative limitations. Intraoperative fluorescein is being studied as a means of marking abnor-mal tissue that appears grossly normal in order to maximize resection and minimize recurrence. Indications for SRS are expanding and provide a noninvasive option that can be used as monotherapy or as supplemental therapy to operative inter-vention. Moreover, new minimally invasive techniques, such as MRI-guided laser interstitial thermal therapy (MRgLITT), are actively being studied for less morbid access to otherwise difficult-to-reach tumors.SPINE: BASIC CONCEPTSThe spine is a complex structure and is subject to an extensive array of pathologic processes, including degeneration,
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Surgery_Schwartz. treatment of GBM. In this approach, immune cells such as T cells and dendritic cells are leveraged to target tumor-specific tissue. These approaches will play an important role as adjuvant therapy to neurosurgical approaches.Recent advances in neurosurgical technology are being used to address previous operative limitations. Intraoperative fluorescein is being studied as a means of marking abnor-mal tissue that appears grossly normal in order to maximize resection and minimize recurrence. Indications for SRS are expanding and provide a noninvasive option that can be used as monotherapy or as supplemental therapy to operative inter-vention. Moreover, new minimally invasive techniques, such as MRI-guided laser interstitial thermal therapy (MRgLITT), are actively being studied for less morbid access to otherwise difficult-to-reach tumors.SPINE: BASIC CONCEPTSThe spine is a complex structure and is subject to an extensive array of pathologic processes, including degeneration,
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Surgery_Schwartz_12317
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less morbid access to otherwise difficult-to-reach tumors.SPINE: BASIC CONCEPTSThe spine is a complex structure and is subject to an extensive array of pathologic processes, including degeneration, inflam-mation, infection, neoplasia, and trauma. Discussions of spine trauma, tumor, and infection are addressed separately in this chapter in the “Infection—Spine,” “Spinal Tumors,” and “Spine Trauma” sections. General concepts, common patterns of dis-ease, and basic operative interventions are presented here.The spine consists of a series of stacked vertebrae, inter-vening discs, and longitudinal ligaments. The vertebrae consist of the vertebral body anteriorly and the pedicles, articular facets, laminae, and spinous processes posteriorly. The intervertebral discs have two components. The tough, fibrous ring that runs around the outer diameter of the two adjacent vertebral bodies is known as the annulus fibrosus. The spongy material inside the ring of the annulus is known as the nucleus
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Surgery_Schwartz. less morbid access to otherwise difficult-to-reach tumors.SPINE: BASIC CONCEPTSThe spine is a complex structure and is subject to an extensive array of pathologic processes, including degeneration, inflam-mation, infection, neoplasia, and trauma. Discussions of spine trauma, tumor, and infection are addressed separately in this chapter in the “Infection—Spine,” “Spinal Tumors,” and “Spine Trauma” sections. General concepts, common patterns of dis-ease, and basic operative interventions are presented here.The spine consists of a series of stacked vertebrae, inter-vening discs, and longitudinal ligaments. The vertebrae consist of the vertebral body anteriorly and the pedicles, articular facets, laminae, and spinous processes posteriorly. The intervertebral discs have two components. The tough, fibrous ring that runs around the outer diameter of the two adjacent vertebral bodies is known as the annulus fibrosus. The spongy material inside the ring of the annulus is known as the nucleus
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Surgery_Schwartz_12318
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fibrous ring that runs around the outer diameter of the two adjacent vertebral bodies is known as the annulus fibrosus. The spongy material inside the ring of the annulus is known as the nucleus pulposus. The annu-lus and the nucleus provide a cushion between adjacent verte-bral bodies, absorb forces transmitted to the spine, and allow some movement between the vertebral bodies. The ligaments stabilize the spine by limiting the motion of adjacent vertebrae.Stability and neural compression are the two concepts crit-ical to understanding the mechanics and pathologic processes affecting the spine.StabilityThe spinal column is the principal structural component of the axial spine, and it must bear significant loads. The vertebrae increase in size from the top to the bottom of the spine, cor-relating with the increased total loads that the more caudal ele-ments must bear. The cervical spine is the most mobile. Cervical stability depends greatly on the integrity of the ligaments that run
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Surgery_Schwartz. fibrous ring that runs around the outer diameter of the two adjacent vertebral bodies is known as the annulus fibrosus. The spongy material inside the ring of the annulus is known as the nucleus pulposus. The annu-lus and the nucleus provide a cushion between adjacent verte-bral bodies, absorb forces transmitted to the spine, and allow some movement between the vertebral bodies. The ligaments stabilize the spine by limiting the motion of adjacent vertebrae.Stability and neural compression are the two concepts crit-ical to understanding the mechanics and pathologic processes affecting the spine.StabilityThe spinal column is the principal structural component of the axial spine, and it must bear significant loads. The vertebrae increase in size from the top to the bottom of the spine, cor-relating with the increased total loads that the more caudal ele-ments must bear. The cervical spine is the most mobile. Cervical stability depends greatly on the integrity of the ligaments that run
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Surgery_Schwartz_12319
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with the increased total loads that the more caudal ele-ments must bear. The cervical spine is the most mobile. Cervical stability depends greatly on the integrity of the ligaments that run from level to level. The thoracic spine is the least mobile, due to the stabilizing effect of the rib cage. The lumbar spine has relatively massive vertebrae, supports heavy loads, and has Brunicardi_Ch42_p1827-p1878.indd 186101/03/19 7:17 PM 1862SPECIFIC CONSIDERATIONSPART IIintermediate mobility. The sacral spine is fused together and has no intrinsic mobility. The load borne by the lumbar spine is transmitted to the sacrum, and then the pelvis through the sacro-iliac joints. The coccyx is the most inferior segment of the spine and has no significant contribution to load bearing or mobility.A stable spine is one that can bear normally experienced forces resulting from body mass, movement, and muscle con-traction, while maintaining normal structure and alignment. An unstable spine will shift
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Surgery_Schwartz. with the increased total loads that the more caudal ele-ments must bear. The cervical spine is the most mobile. Cervical stability depends greatly on the integrity of the ligaments that run from level to level. The thoracic spine is the least mobile, due to the stabilizing effect of the rib cage. The lumbar spine has relatively massive vertebrae, supports heavy loads, and has Brunicardi_Ch42_p1827-p1878.indd 186101/03/19 7:17 PM 1862SPECIFIC CONSIDERATIONSPART IIintermediate mobility. The sacral spine is fused together and has no intrinsic mobility. The load borne by the lumbar spine is transmitted to the sacrum, and then the pelvis through the sacro-iliac joints. The coccyx is the most inferior segment of the spine and has no significant contribution to load bearing or mobility.A stable spine is one that can bear normally experienced forces resulting from body mass, movement, and muscle con-traction, while maintaining normal structure and alignment. An unstable spine will shift
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spine is one that can bear normally experienced forces resulting from body mass, movement, and muscle con-traction, while maintaining normal structure and alignment. An unstable spine will shift or sublux under these forces. The determinants of spinal stability vary throughout the cervical, thoracic, and lumbar portions. In elementary form, stability depends on the structural integrity of the hard, bony elements of the vertebral column, as well as the tensile integrity and security of the supporting ligamentous attachments. Plain X-rays and CT scans are sensitive for detecting bony defects such as frac-tures or subluxation, while MRI better detects disruptions of the soft tissues, including ligaments and intervertebral discs. Specific patterns of abnormalities seen on imaging studies may suggest or diagnose spinal instability.A common form of nontraumatic spinal instability is lum-bar spondylolisthesis, which is typically a forward slippage of a lumbar vertebra relative to the lower
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Surgery_Schwartz. spine is one that can bear normally experienced forces resulting from body mass, movement, and muscle con-traction, while maintaining normal structure and alignment. An unstable spine will shift or sublux under these forces. The determinants of spinal stability vary throughout the cervical, thoracic, and lumbar portions. In elementary form, stability depends on the structural integrity of the hard, bony elements of the vertebral column, as well as the tensile integrity and security of the supporting ligamentous attachments. Plain X-rays and CT scans are sensitive for detecting bony defects such as frac-tures or subluxation, while MRI better detects disruptions of the soft tissues, including ligaments and intervertebral discs. Specific patterns of abnormalities seen on imaging studies may suggest or diagnose spinal instability.A common form of nontraumatic spinal instability is lum-bar spondylolisthesis, which is typically a forward slippage of a lumbar vertebra relative to the lower
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suggest or diagnose spinal instability.A common form of nontraumatic spinal instability is lum-bar spondylolisthesis, which is typically a forward slippage of a lumbar vertebra relative to the lower vertebra on which it rests. This results from congenital or degenerative disruption of the pars interarticularis, the critical bridge of bone that spans adja-cent facet joints. In the setting of a pars defect, there is no solid bony connection between the adjacent vertebrae. The spine is unstable and anterior listhesis (slippage) may result. Patients typically present with severe low back pain that is exacerbated with movement and load bearing (mechanical low back pain). Radiculopathy in this setting indicates neuroforaminal compres-sion. Figure 42-27 demonstrates an L4 and L5 spondylolisthesis.Neural CompressionBesides providing a stable, central element of the body’s support structure, the spine also protects the spinal cord and nerve roots as they pass through the neural foramina to
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Surgery_Schwartz. suggest or diagnose spinal instability.A common form of nontraumatic spinal instability is lum-bar spondylolisthesis, which is typically a forward slippage of a lumbar vertebra relative to the lower vertebra on which it rests. This results from congenital or degenerative disruption of the pars interarticularis, the critical bridge of bone that spans adja-cent facet joints. In the setting of a pars defect, there is no solid bony connection between the adjacent vertebrae. The spine is unstable and anterior listhesis (slippage) may result. Patients typically present with severe low back pain that is exacerbated with movement and load bearing (mechanical low back pain). Radiculopathy in this setting indicates neuroforaminal compres-sion. Figure 42-27 demonstrates an L4 and L5 spondylolisthesis.Neural CompressionBesides providing a stable, central element of the body’s support structure, the spine also protects the spinal cord and nerve roots as they pass through the neural foramina to
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CompressionBesides providing a stable, central element of the body’s support structure, the spine also protects the spinal cord and nerve roots as they pass through the neural foramina to form the peripheral nervous system. In a healthy spine, the spinal cord and nerve roots are suspended in CSF, free of mechanical compression. Patho-logic processes that can lead to CSF space impingement and neural compression include: hypertrophic degenerative changes in the intervertebral discs and facet joints, expansion of epidural masses such as tumors or abscesses, and subluxation (i.e., slip-page) of adjacent vertebral bodies. Subluxation may be due to trauma that exceeds the spine’s load-bearing capabilities and leads to structural failure, or chronic structural degradation by degenerative disease, infection, or tumor. Subluxation reduces the cross-sectional area of the central canal and the neural foramina (see Fig. 42-10B). Reduced central canal area can lead to myelop-athy. Reduced neural
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Surgery_Schwartz. CompressionBesides providing a stable, central element of the body’s support structure, the spine also protects the spinal cord and nerve roots as they pass through the neural foramina to form the peripheral nervous system. In a healthy spine, the spinal cord and nerve roots are suspended in CSF, free of mechanical compression. Patho-logic processes that can lead to CSF space impingement and neural compression include: hypertrophic degenerative changes in the intervertebral discs and facet joints, expansion of epidural masses such as tumors or abscesses, and subluxation (i.e., slip-page) of adjacent vertebral bodies. Subluxation may be due to trauma that exceeds the spine’s load-bearing capabilities and leads to structural failure, or chronic structural degradation by degenerative disease, infection, or tumor. Subluxation reduces the cross-sectional area of the central canal and the neural foramina (see Fig. 42-10B). Reduced central canal area can lead to myelop-athy. Reduced neural
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infection, or tumor. Subluxation reduces the cross-sectional area of the central canal and the neural foramina (see Fig. 42-10B). Reduced central canal area can lead to myelop-athy. Reduced neural foraminal area can lead to radiculopathy.Myelopathy. Compression of the spinal cord can cause distur-bance of function known as myelopathy. This dysfunction may be secondary to the direct effects of compression, cord isch-emia due to reduced perfusion, or pathologic changes due to repeated cord trauma. These mechanisms lead to demyelination of the corticospinal tracts, which are long descending motor tracts. Corticospinal tract damage leads to upper motor neuron signs and symptoms, including hyperreflexia, spasticity, and weakness. These mechanisms also cause damage to the dorsal columns, which carry ascending proprioception, vibration, and two-point discrimination information. Loss of proprioception makes fine motor tasks and ambulation difficult.Radiculopathy. Compression of the nerve
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Surgery_Schwartz. infection, or tumor. Subluxation reduces the cross-sectional area of the central canal and the neural foramina (see Fig. 42-10B). Reduced central canal area can lead to myelop-athy. Reduced neural foraminal area can lead to radiculopathy.Myelopathy. Compression of the spinal cord can cause distur-bance of function known as myelopathy. This dysfunction may be secondary to the direct effects of compression, cord isch-emia due to reduced perfusion, or pathologic changes due to repeated cord trauma. These mechanisms lead to demyelination of the corticospinal tracts, which are long descending motor tracts. Corticospinal tract damage leads to upper motor neuron signs and symptoms, including hyperreflexia, spasticity, and weakness. These mechanisms also cause damage to the dorsal columns, which carry ascending proprioception, vibration, and two-point discrimination information. Loss of proprioception makes fine motor tasks and ambulation difficult.Radiculopathy. Compression of the nerve
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carry ascending proprioception, vibration, and two-point discrimination information. Loss of proprioception makes fine motor tasks and ambulation difficult.Radiculopathy. Compression of the nerve roots causes distur-bance of root function, known as radiculopathy. Characteristic features of radiculopathy include lower motor neuron signs and symptoms (hyporeflexia, atrophy, and weakness) and sensory dis-turbances such as numbness or tingling sensations (paresthesias), burning sensations (dysesthesias), and shooting (radicular) pain. Myelopathy and radiculopathy often present together in diseases that involve the central canal and the neural foramina. This com-bination can lead to lower motor neuron dysfunction at the level of disease, and upper motor neuron dysfunction below that level.Patterns of DiseaseCervical Radiculopathy. The cervical nerve roots exit the central canal above the pedicle of the same-numbered verte-bra and at the level of the higher adjacent intervertebral disc. For
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Surgery_Schwartz. carry ascending proprioception, vibration, and two-point discrimination information. Loss of proprioception makes fine motor tasks and ambulation difficult.Radiculopathy. Compression of the nerve roots causes distur-bance of root function, known as radiculopathy. Characteristic features of radiculopathy include lower motor neuron signs and symptoms (hyporeflexia, atrophy, and weakness) and sensory dis-turbances such as numbness or tingling sensations (paresthesias), burning sensations (dysesthesias), and shooting (radicular) pain. Myelopathy and radiculopathy often present together in diseases that involve the central canal and the neural foramina. This com-bination can lead to lower motor neuron dysfunction at the level of disease, and upper motor neuron dysfunction below that level.Patterns of DiseaseCervical Radiculopathy. The cervical nerve roots exit the central canal above the pedicle of the same-numbered verte-bra and at the level of the higher adjacent intervertebral disc. For
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of DiseaseCervical Radiculopathy. The cervical nerve roots exit the central canal above the pedicle of the same-numbered verte-bra and at the level of the higher adjacent intervertebral disc. For example, the C6 nerve root passes above the C6 pedicle at the level of the C5–C6 discs. The cervical nerve roots may be compressed acutely by disc herniation, or chronically by hypertrophic degenerative changes of the discs, facets, and liga-ments. Table 42-6 summarizes the effects of various disc her-niations. Most patients with acute disc herniations will improve without surgery. NSAIDs or cervical traction may help alle-viate symptoms. Patients whose symptoms do not resolve or who have significant weakness should undergo decompressive surgery. The two main options for nerve root decompression are anterior cervical discectomy and fusion (ACDF) and posterior cervical foraminotomy (keyhole foraminotomy). ACDF allows more direct access to and removal of the pathology (anterior to the nerve
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Surgery_Schwartz. of DiseaseCervical Radiculopathy. The cervical nerve roots exit the central canal above the pedicle of the same-numbered verte-bra and at the level of the higher adjacent intervertebral disc. For example, the C6 nerve root passes above the C6 pedicle at the level of the C5–C6 discs. The cervical nerve roots may be compressed acutely by disc herniation, or chronically by hypertrophic degenerative changes of the discs, facets, and liga-ments. Table 42-6 summarizes the effects of various disc her-niations. Most patients with acute disc herniations will improve without surgery. NSAIDs or cervical traction may help alle-viate symptoms. Patients whose symptoms do not resolve or who have significant weakness should undergo decompressive surgery. The two main options for nerve root decompression are anterior cervical discectomy and fusion (ACDF) and posterior cervical foraminotomy (keyhole foraminotomy). ACDF allows more direct access to and removal of the pathology (anterior to the nerve
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are anterior cervical discectomy and fusion (ACDF) and posterior cervical foraminotomy (keyhole foraminotomy). ACDF allows more direct access to and removal of the pathology (anterior to the nerve root). However, the procedure requires fusion because discectomy causes a collapse of the interbody space and instabil-ity will likely occur. Figure 42-28 demonstrates a C6–C7 ACDF with the typical interposed graft and plating system. Keyhole foraminotomy allows for decompression without requiring Figure 42-27. Lateral lumbar spine X-ray demonstrates a 25% anterior slippage of L4 on L5 due to a defect in the L4 pars interar-ticularis. This is called spondylolisthesis.Brunicardi_Ch42_p1827-p1878.indd 186201/03/19 7:17 PM 1863NEUROSURGERYCHAPTER 42Table 42-6Cervical disc herniations and symptoms by levelLEVELFREQUENCY (%)ROOT INJUREDREFLEXWEAKNESSNUMBNESSC4–C52C5—DeltoidShoulderC5–C619C6BicepsBiceps brachiiThumbC6–C769C7TricepsWrist extensors (wrist drop)Second and third
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Surgery_Schwartz. are anterior cervical discectomy and fusion (ACDF) and posterior cervical foraminotomy (keyhole foraminotomy). ACDF allows more direct access to and removal of the pathology (anterior to the nerve root). However, the procedure requires fusion because discectomy causes a collapse of the interbody space and instabil-ity will likely occur. Figure 42-28 demonstrates a C6–C7 ACDF with the typical interposed graft and plating system. Keyhole foraminotomy allows for decompression without requiring Figure 42-27. Lateral lumbar spine X-ray demonstrates a 25% anterior slippage of L4 on L5 due to a defect in the L4 pars interar-ticularis. This is called spondylolisthesis.Brunicardi_Ch42_p1827-p1878.indd 186201/03/19 7:17 PM 1863NEUROSURGERYCHAPTER 42Table 42-6Cervical disc herniations and symptoms by levelLEVELFREQUENCY (%)ROOT INJUREDREFLEXWEAKNESSNUMBNESSC4–C52C5—DeltoidShoulderC5–C619C6BicepsBiceps brachiiThumbC6–C769C7TricepsWrist extensors (wrist drop)Second and third
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and symptoms by levelLEVELFREQUENCY (%)ROOT INJUREDREFLEXWEAKNESSNUMBNESSC4–C52C5—DeltoidShoulderC5–C619C6BicepsBiceps brachiiThumbC6–C769C7TricepsWrist extensors (wrist drop)Second and third digitsC7–T110C8—Hand intrinsicsFourth and fifth digitsAdapted with permission from Greenberg MS. Handbook of Neurosurgery, 7th ed. New York, NY: Thieme; 2010.BAFigure 42-28. A. Anteroposterior cervical spine X-ray showing the position of an anterior cervical plate used for stabilization after C6–C7 discectomy. Patient presented with right triceps weakness and dysesthesias in the right fifth digit. Magnetic resonance imaging revealed a right paracentral C6–C7 herniated disc compressing the exiting C7 nerve root. B. Lateral cervical spine X-ray of the same patient clearly demonstrates the position of the plate and screws. The allograft bone spacer placed in the drilled-out disc space is also apparent.fusion, but it is less effective for removing centrally located canal pathology.Cervical
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Surgery_Schwartz. and symptoms by levelLEVELFREQUENCY (%)ROOT INJUREDREFLEXWEAKNESSNUMBNESSC4–C52C5—DeltoidShoulderC5–C619C6BicepsBiceps brachiiThumbC6–C769C7TricepsWrist extensors (wrist drop)Second and third digitsC7–T110C8—Hand intrinsicsFourth and fifth digitsAdapted with permission from Greenberg MS. Handbook of Neurosurgery, 7th ed. New York, NY: Thieme; 2010.BAFigure 42-28. A. Anteroposterior cervical spine X-ray showing the position of an anterior cervical plate used for stabilization after C6–C7 discectomy. Patient presented with right triceps weakness and dysesthesias in the right fifth digit. Magnetic resonance imaging revealed a right paracentral C6–C7 herniated disc compressing the exiting C7 nerve root. B. Lateral cervical spine X-ray of the same patient clearly demonstrates the position of the plate and screws. The allograft bone spacer placed in the drilled-out disc space is also apparent.fusion, but it is less effective for removing centrally located canal pathology.Cervical
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of the plate and screws. The allograft bone spacer placed in the drilled-out disc space is also apparent.fusion, but it is less effective for removing centrally located canal pathology.Cervical Spondylotic Myelopathy. The term spondylosis refers to diffuse degenerative and hypertrophic changes of the discs, intervertebral joints, and ligaments, which collectively result in spinal stenosis. Spinal cord dysfunction (myelopathy) due to cord compression from cervical spinal degenerative dis-ease is therefore referred to as cervical spondylotic myelopathy (CSM). Classically CSM presents with spasticity and hyper-reflexia due to corticospinal tract dysfunction, upper extremity weakness and atrophy from degeneration of the motor neu-rons in the anterior horns of the spinal gray matter, and loss of lower extremity proprioception due to dorsal column injury. Figure 42-29 demonstrates typical findings. Some patients com-plain of difficulty buttoning shirts, using utensils, and ambulating.
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Surgery_Schwartz. of the plate and screws. The allograft bone spacer placed in the drilled-out disc space is also apparent.fusion, but it is less effective for removing centrally located canal pathology.Cervical Spondylotic Myelopathy. The term spondylosis refers to diffuse degenerative and hypertrophic changes of the discs, intervertebral joints, and ligaments, which collectively result in spinal stenosis. Spinal cord dysfunction (myelopathy) due to cord compression from cervical spinal degenerative dis-ease is therefore referred to as cervical spondylotic myelopathy (CSM). Classically CSM presents with spasticity and hyper-reflexia due to corticospinal tract dysfunction, upper extremity weakness and atrophy from degeneration of the motor neu-rons in the anterior horns of the spinal gray matter, and loss of lower extremity proprioception due to dorsal column injury. Figure 42-29 demonstrates typical findings. Some patients com-plain of difficulty buttoning shirts, using utensils, and ambulating.
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of lower extremity proprioception due to dorsal column injury. Figure 42-29 demonstrates typical findings. Some patients com-plain of difficulty buttoning shirts, using utensils, and ambulating. Spondylosis is usually diffuse, so the usual treatment for CSM is multilevel (usually C3–C7) cervical laminectomy, although patients with disease localized over one to three levels may be can-didates for anterior decompression and fusion. Fig. 42-30 demon-strates the postoperative appearance of a vertebral corpectomy and fusion for CSM. Thorough cervical laminectomy decompresses the cord posteriorly. Patients often have slow recovery due to the extensive chronic changes in the cervical cord and may benefit from rehabilitation programs. The other disease that classically presents with combined upper and lower motor neuron symp-toms is amyotrophic lateral sclerosis (ALS). Care must be taken Brunicardi_Ch42_p1827-p1878.indd 186301/03/19 7:17 PM 1864SPECIFIC CONSIDERATIONSPART IIto avoid
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Surgery_Schwartz. of lower extremity proprioception due to dorsal column injury. Figure 42-29 demonstrates typical findings. Some patients com-plain of difficulty buttoning shirts, using utensils, and ambulating. Spondylosis is usually diffuse, so the usual treatment for CSM is multilevel (usually C3–C7) cervical laminectomy, although patients with disease localized over one to three levels may be can-didates for anterior decompression and fusion. Fig. 42-30 demon-strates the postoperative appearance of a vertebral corpectomy and fusion for CSM. Thorough cervical laminectomy decompresses the cord posteriorly. Patients often have slow recovery due to the extensive chronic changes in the cervical cord and may benefit from rehabilitation programs. The other disease that classically presents with combined upper and lower motor neuron symp-toms is amyotrophic lateral sclerosis (ALS). Care must be taken Brunicardi_Ch42_p1827-p1878.indd 186301/03/19 7:17 PM 1864SPECIFIC CONSIDERATIONSPART IIto avoid
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upper and lower motor neuron symp-toms is amyotrophic lateral sclerosis (ALS). Care must be taken Brunicardi_Ch42_p1827-p1878.indd 186301/03/19 7:17 PM 1864SPECIFIC CONSIDERATIONSPART IIto avoid offering cervical laminectomy to a patient with undi-agnosed ALS. Two findings help differentiate CSM from ALS: cranial nerve dysfunction such as dysphagia (not typically caused by cervical spine disease) and sensory disturbance (not found in ALS).Thoracic Disc Herniation. Thoracic disc herniation accounts for <1% of herniated discs. A patient may present with radicular pain or sensorimotor changes in the lower extremities due to cord compression. A posterior approach via midline incision and lami-nectomy should be avoided because of the high incidence of cord injury from manipulation and retraction. Anterior approaches via thoracotomy minimize risk to the cord and allow excellent access to the disc. The radicular arteries running from the aorta to the thoracic cord should be spared, when
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Surgery_Schwartz. upper and lower motor neuron symp-toms is amyotrophic lateral sclerosis (ALS). Care must be taken Brunicardi_Ch42_p1827-p1878.indd 186301/03/19 7:17 PM 1864SPECIFIC CONSIDERATIONSPART IIto avoid offering cervical laminectomy to a patient with undi-agnosed ALS. Two findings help differentiate CSM from ALS: cranial nerve dysfunction such as dysphagia (not typically caused by cervical spine disease) and sensory disturbance (not found in ALS).Thoracic Disc Herniation. Thoracic disc herniation accounts for <1% of herniated discs. A patient may present with radicular pain or sensorimotor changes in the lower extremities due to cord compression. A posterior approach via midline incision and lami-nectomy should be avoided because of the high incidence of cord injury from manipulation and retraction. Anterior approaches via thoracotomy minimize risk to the cord and allow excellent access to the disc. The radicular arteries running from the aorta to the thoracic cord should be spared, when
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Anterior approaches via thoracotomy minimize risk to the cord and allow excellent access to the disc. The radicular arteries running from the aorta to the thoracic cord should be spared, when possible, to avoid ischemia. Alternatively, a posterolateral approach is possible via resection of the rib head and facet joint. Finally, a transpedicular approach may be attempted for lateral disc herniations.73Lumbar Radiculopathy. Lumbar nerve roots exit the thecal sac, pass over the higher adjacent disc space, and exit the canal under the pedicle of the same-numbered vertebra. Therefore, the L5 nerve root passes over the L4–L5 disc space and exits under the L5 pedicle (Fig. 42-31). Lumbar discs may herniate with or without a history of trauma or straining. Normally they cause lancinating (radicular) pain down the leg (Table 42-7). Most acute herniated lumbar discs improve symptomatically without surgery. Surgery is indicated for symptoms persisting more than 6 to 8 weeks, progressive motor
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Surgery_Schwartz. Anterior approaches via thoracotomy minimize risk to the cord and allow excellent access to the disc. The radicular arteries running from the aorta to the thoracic cord should be spared, when possible, to avoid ischemia. Alternatively, a posterolateral approach is possible via resection of the rib head and facet joint. Finally, a transpedicular approach may be attempted for lateral disc herniations.73Lumbar Radiculopathy. Lumbar nerve roots exit the thecal sac, pass over the higher adjacent disc space, and exit the canal under the pedicle of the same-numbered vertebra. Therefore, the L5 nerve root passes over the L4–L5 disc space and exits under the L5 pedicle (Fig. 42-31). Lumbar discs may herniate with or without a history of trauma or straining. Normally they cause lancinating (radicular) pain down the leg (Table 42-7). Most acute herniated lumbar discs improve symptomatically without surgery. Surgery is indicated for symptoms persisting more than 6 to 8 weeks, progressive motor
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pain down the leg (Table 42-7). Most acute herniated lumbar discs improve symptomatically without surgery. Surgery is indicated for symptoms persisting more than 6 to 8 weeks, progressive motor deficit (e.g., foot drop), or for patients with incapacitating pain not manage-able with analgesics. A recent randomized control trial (Spine Patients Outcome Research Trial [SPORT])74 did not observe significant differences between patients randomized to undergo surgery vs. conservative management when using an intent-to-treat analysis. Because of the high amount of bi-directional cross-over between the surgery and conservative group, a sub-sequent reanalysis of the data as observational cohort analysis, demonstrated improved functional outcomes in terms of pain and physical function, more so at 3 months than at 2 years.74Discectomy is performed using a midline incision, partial removal of the overlying laminae (hemilaminectomy or lami-notomy), identification of the thecal sac and nerve root,
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Surgery_Schwartz. pain down the leg (Table 42-7). Most acute herniated lumbar discs improve symptomatically without surgery. Surgery is indicated for symptoms persisting more than 6 to 8 weeks, progressive motor deficit (e.g., foot drop), or for patients with incapacitating pain not manage-able with analgesics. A recent randomized control trial (Spine Patients Outcome Research Trial [SPORT])74 did not observe significant differences between patients randomized to undergo surgery vs. conservative management when using an intent-to-treat analysis. Because of the high amount of bi-directional cross-over between the surgery and conservative group, a sub-sequent reanalysis of the data as observational cohort analysis, demonstrated improved functional outcomes in terms of pain and physical function, more so at 3 months than at 2 years.74Discectomy is performed using a midline incision, partial removal of the overlying laminae (hemilaminectomy or lami-notomy), identification of the thecal sac and nerve root,
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months than at 2 years.74Discectomy is performed using a midline incision, partial removal of the overlying laminae (hemilaminectomy or lami-notomy), identification of the thecal sac and nerve root, and extraction of disc fragments. Free-floating disc fragments may be found. Often, however, the herniated disc material is still contained within the annulus, requiring incision of the poste-rior longitudinal ligament and curettage of the disc space. After lumbar discectomy, approximately two-thirds of patients will have complete relief of pain, and up to 85% will have significant improvement.Neurogenic Claudication. Neurogenic claudication is char-acterized by low back and leg pain that occurs while walking and is relieved by stopping, leaning forward, or sitting. It is normally caused by degenerative lumbar stenosis causing com-pression of the cauda equina. Neurogenic claudication must be distinguished from vascular claudication, which tends to resolve quickly with cessation of walking.
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Surgery_Schwartz. months than at 2 years.74Discectomy is performed using a midline incision, partial removal of the overlying laminae (hemilaminectomy or lami-notomy), identification of the thecal sac and nerve root, and extraction of disc fragments. Free-floating disc fragments may be found. Often, however, the herniated disc material is still contained within the annulus, requiring incision of the poste-rior longitudinal ligament and curettage of the disc space. After lumbar discectomy, approximately two-thirds of patients will have complete relief of pain, and up to 85% will have significant improvement.Neurogenic Claudication. Neurogenic claudication is char-acterized by low back and leg pain that occurs while walking and is relieved by stopping, leaning forward, or sitting. It is normally caused by degenerative lumbar stenosis causing com-pression of the cauda equina. Neurogenic claudication must be distinguished from vascular claudication, which tends to resolve quickly with cessation of walking.
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lumbar stenosis causing com-pression of the cauda equina. Neurogenic claudication must be distinguished from vascular claudication, which tends to resolve quickly with cessation of walking. There is typically no need to change position, and the pain follows a stocking distribution rather than a dermatomal distribution. Pallor and coldness of the feet, and normal neurologic examination are also typical, though diabetic patients may present a challenge with microvascular Figure 42-29. T2-weighted sagittal magnetic resonance imaging of the cervical spine showing multilevel degenerative changes caus-ing spinal stenosis that is worst at C5–C6. Note the bright signal within the cord at that level, consistent with myelopathy.Figure 42-30. Lateral cervical spine X-ray status post C5 corpec-tomy for cervical spondylotic myelopathy. This involves removal of the C4–C5 disc, C5 vertebral body, and C5–C6 disc, decom-pressing at two levels. A bone strut is visible bridging C4 to C6. The plate and
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Surgery_Schwartz. lumbar stenosis causing com-pression of the cauda equina. Neurogenic claudication must be distinguished from vascular claudication, which tends to resolve quickly with cessation of walking. There is typically no need to change position, and the pain follows a stocking distribution rather than a dermatomal distribution. Pallor and coldness of the feet, and normal neurologic examination are also typical, though diabetic patients may present a challenge with microvascular Figure 42-29. T2-weighted sagittal magnetic resonance imaging of the cervical spine showing multilevel degenerative changes caus-ing spinal stenosis that is worst at C5–C6. Note the bright signal within the cord at that level, consistent with myelopathy.Figure 42-30. Lateral cervical spine X-ray status post C5 corpec-tomy for cervical spondylotic myelopathy. This involves removal of the C4–C5 disc, C5 vertebral body, and C5–C6 disc, decom-pressing at two levels. A bone strut is visible bridging C4 to C6. The plate and
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for cervical spondylotic myelopathy. This involves removal of the C4–C5 disc, C5 vertebral body, and C5–C6 disc, decom-pressing at two levels. A bone strut is visible bridging C4 to C6. The plate and screws stabilize the segments.Brunicardi_Ch42_p1827-p1878.indd 186401/03/19 7:17 PM 1865NEUROSURGERYCHAPTER 42neuropathy. Patients with neurogenic claudication have a slowly progressive course and may be surgical candidates when their pain interferes with their lifestyle. The usual surgery is an L3 to L5 lumbar laminectomy to decompress the nerve roots. A recent randomized control trial did not observe a significant difference in outcomes between surgical and conservative management of lumbar stenosis at 1 year.75 Thus, surgical management of lum-bar stenosis should be reserved for patients that do not improve with physical therapy.Cauda Equina Syndrome. Cauda equina syndrome is due to compression of the cauda equina and may result from massive disc herniation, EDH, epidural abscess,
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Surgery_Schwartz. for cervical spondylotic myelopathy. This involves removal of the C4–C5 disc, C5 vertebral body, and C5–C6 disc, decom-pressing at two levels. A bone strut is visible bridging C4 to C6. The plate and screws stabilize the segments.Brunicardi_Ch42_p1827-p1878.indd 186401/03/19 7:17 PM 1865NEUROSURGERYCHAPTER 42neuropathy. Patients with neurogenic claudication have a slowly progressive course and may be surgical candidates when their pain interferes with their lifestyle. The usual surgery is an L3 to L5 lumbar laminectomy to decompress the nerve roots. A recent randomized control trial did not observe a significant difference in outcomes between surgical and conservative management of lumbar stenosis at 1 year.75 Thus, surgical management of lum-bar stenosis should be reserved for patients that do not improve with physical therapy.Cauda Equina Syndrome. Cauda equina syndrome is due to compression of the cauda equina and may result from massive disc herniation, EDH, epidural abscess,
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that do not improve with physical therapy.Cauda Equina Syndrome. Cauda equina syndrome is due to compression of the cauda equina and may result from massive disc herniation, EDH, epidural abscess, tumor, or subluxation from trauma. Patients with cauda equina compression often present with urinary retention, saddle anesthesia, or progressing leg weakness. Saddle anesthesia is numbness in the perineum, genitals, buttocks, and upper inner thighs. Patients with sus-pected cauda equina syndrome should undergo immediate MRI of the lumbar spine to evaluate for a surgical lesion. Mass lesions should be removed urgently via laminectomy to preserve sphincter function and ambulation.Spine Fusion SurgeryFusion surgery is often required for patients with spinal instabil-ity resulting from disease, surgical intervention, or both. Fusion procedures lock adjacent vertebrae together. Fusion occurs when the body forms a solid mass of bone incorporating the adjacent vertebrae, eliminating normal
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Surgery_Schwartz. that do not improve with physical therapy.Cauda Equina Syndrome. Cauda equina syndrome is due to compression of the cauda equina and may result from massive disc herniation, EDH, epidural abscess, tumor, or subluxation from trauma. Patients with cauda equina compression often present with urinary retention, saddle anesthesia, or progressing leg weakness. Saddle anesthesia is numbness in the perineum, genitals, buttocks, and upper inner thighs. Patients with sus-pected cauda equina syndrome should undergo immediate MRI of the lumbar spine to evaluate for a surgical lesion. Mass lesions should be removed urgently via laminectomy to preserve sphincter function and ambulation.Spine Fusion SurgeryFusion surgery is often required for patients with spinal instabil-ity resulting from disease, surgical intervention, or both. Fusion procedures lock adjacent vertebrae together. Fusion occurs when the body forms a solid mass of bone incorporating the adjacent vertebrae, eliminating normal
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surgical intervention, or both. Fusion procedures lock adjacent vertebrae together. Fusion occurs when the body forms a solid mass of bone incorporating the adjacent vertebrae, eliminating normal intervertebral move-ment. Stabilization and immobilization promote bony fusion. Internal instrumentation and external orthoses are often used to stabilize and immobilize the fused spinal segments.Spinal InstrumentationInternal fixation devices for spinal segmental immobilization have been developed for all levels of the spine. Most spinal instrumentation constructs have two elements. The first element is a device that solidly attaches to the vertebral bodies. Options include wires wrapped around laminae or spi-nous processes, hooks placed under the lamina or around the pedicles, or screws placed in the pedicles or the vertebral bodies. The second element is a device that traverses vertebral seg-ments. Options include rods and plates that lock directly to the wires, hooks, or screws at each
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Surgery_Schwartz. surgical intervention, or both. Fusion procedures lock adjacent vertebrae together. Fusion occurs when the body forms a solid mass of bone incorporating the adjacent vertebrae, eliminating normal intervertebral move-ment. Stabilization and immobilization promote bony fusion. Internal instrumentation and external orthoses are often used to stabilize and immobilize the fused spinal segments.Spinal InstrumentationInternal fixation devices for spinal segmental immobilization have been developed for all levels of the spine. Most spinal instrumentation constructs have two elements. The first element is a device that solidly attaches to the vertebral bodies. Options include wires wrapped around laminae or spi-nous processes, hooks placed under the lamina or around the pedicles, or screws placed in the pedicles or the vertebral bodies. The second element is a device that traverses vertebral seg-ments. Options include rods and plates that lock directly to the wires, hooks, or screws at each
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in the pedicles or the vertebral bodies. The second element is a device that traverses vertebral seg-ments. Options include rods and plates that lock directly to the wires, hooks, or screws at each vertebral level. Spinal instru-mentation devices are available for anterior and posterior fusion in the cervical, thoracic, and lumbar regions. Most modern spi-nal instrumentation devices are made of titanium to minimize problems with future MRI scanning (Fig. 42-32). All spinal instrumentation constructs will eventually fail by loosening or breaking if bony fusion does not occur.6ABFigure 42-31. A. T2-weighted sagittal magnetic resonance imaging shows an L5–S1 disc herniation causing significant canal compromise and displacement of nerve roots. B. T2-weighted axial magnetic resonance imaging of the same patient shows the large left paracentral disc herniation at L5–S1. Arrowheads delineate the extent of the herniation. The arrow indicates the right S1 nerve root passing through free of
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Surgery_Schwartz. in the pedicles or the vertebral bodies. The second element is a device that traverses vertebral seg-ments. Options include rods and plates that lock directly to the wires, hooks, or screws at each vertebral level. Spinal instru-mentation devices are available for anterior and posterior fusion in the cervical, thoracic, and lumbar regions. Most modern spi-nal instrumentation devices are made of titanium to minimize problems with future MRI scanning (Fig. 42-32). All spinal instrumentation constructs will eventually fail by loosening or breaking if bony fusion does not occur.6ABFigure 42-31. A. T2-weighted sagittal magnetic resonance imaging shows an L5–S1 disc herniation causing significant canal compromise and displacement of nerve roots. B. T2-weighted axial magnetic resonance imaging of the same patient shows the large left paracentral disc herniation at L5–S1. Arrowheads delineate the extent of the herniation. The arrow indicates the right S1 nerve root passing through free of
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of the same patient shows the large left paracentral disc herniation at L5–S1. Arrowheads delineate the extent of the herniation. The arrow indicates the right S1 nerve root passing through free of compression. The left S1 nerve root is under severe compression and is not seen.Table 42-7Lumbar disc herniations and symptoms by levelLEVELFREQUENCY (%)ROOT INJUREDREFLEXWEAKNESSNUMBNESSL3–L45L4PatellarQuadricepsAnterior thighL4–L545L5—Tibialis anterior (foot drop)Great toeL5–S150S1AchillesGastrocnemiusLateral footAdapted with permission from Greenberg MS. Handbook of Neurosurgery, 7th ed. New York, NY: Thieme; 2010.Brunicardi_Ch42_p1827-p1878.indd 186501/03/19 7:17 PM 1866SPECIFIC CONSIDERATIONSPART IIFigure 42-32. A. Lateral lumbar spine X-ray showing pedicle screws and connecting rods used to stabilize L4 with respect to L5. This instrumentation was placed as part of a fusion operation to stabilize progressive L4–L5 spondylolisthesis with intractable low back pain. B.
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Surgery_Schwartz. of the same patient shows the large left paracentral disc herniation at L5–S1. Arrowheads delineate the extent of the herniation. The arrow indicates the right S1 nerve root passing through free of compression. The left S1 nerve root is under severe compression and is not seen.Table 42-7Lumbar disc herniations and symptoms by levelLEVELFREQUENCY (%)ROOT INJUREDREFLEXWEAKNESSNUMBNESSL3–L45L4PatellarQuadricepsAnterior thighL4–L545L5—Tibialis anterior (foot drop)Great toeL5–S150S1AchillesGastrocnemiusLateral footAdapted with permission from Greenberg MS. Handbook of Neurosurgery, 7th ed. New York, NY: Thieme; 2010.Brunicardi_Ch42_p1827-p1878.indd 186501/03/19 7:17 PM 1866SPECIFIC CONSIDERATIONSPART IIFigure 42-32. A. Lateral lumbar spine X-ray showing pedicle screws and connecting rods used to stabilize L4 with respect to L5. This instrumentation was placed as part of a fusion operation to stabilize progressive L4–L5 spondylolisthesis with intractable low back pain. B.
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rods used to stabilize L4 with respect to L5. This instrumentation was placed as part of a fusion operation to stabilize progressive L4–L5 spondylolisthesis with intractable low back pain. B. Anteroposterior lumbar spine X-ray showing L3 to L5 instrumentation with pedicle screws and connecting rods. The patient had previously sustained an L4 burst fracture. Note the sig-nificant loss of height of the L4 body compared to adjacent levels. The small row of staples to the right delineates the incision over the iliac crest used to harvest cancellous bone as a nonstructural osteoinductive autograft fusion designed to induce formation of a solid bone bridge from L3 to L5 (arthrodesis).ArthrodesisArthrodesis refers to the obliteration of motion or instability by incorporating the relevant components into a solid mass of bone. Arthrodesis must occur in any fused segment to have long-term stability. Failure of arthrodesis results in failed fusion, often in the form of a fibrous nonunion. The
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Surgery_Schwartz. rods used to stabilize L4 with respect to L5. This instrumentation was placed as part of a fusion operation to stabilize progressive L4–L5 spondylolisthesis with intractable low back pain. B. Anteroposterior lumbar spine X-ray showing L3 to L5 instrumentation with pedicle screws and connecting rods. The patient had previously sustained an L4 burst fracture. Note the sig-nificant loss of height of the L4 body compared to adjacent levels. The small row of staples to the right delineates the incision over the iliac crest used to harvest cancellous bone as a nonstructural osteoinductive autograft fusion designed to induce formation of a solid bone bridge from L3 to L5 (arthrodesis).ArthrodesisArthrodesis refers to the obliteration of motion or instability by incorporating the relevant components into a solid mass of bone. Arthrodesis must occur in any fused segment to have long-term stability. Failure of arthrodesis results in failed fusion, often in the form of a fibrous nonunion. The
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into a solid mass of bone. Arthrodesis must occur in any fused segment to have long-term stability. Failure of arthrodesis results in failed fusion, often in the form of a fibrous nonunion. The rates of successful fusion are higher in the cervical spine than the lum-bar spine. Arthrodesis requires ingrowth of new bone formed by the patient’s osteoblasts across the unstable defect. Insert-ing graft material, such as autograft or allograft, into the defect provides a bridge for osteoblasts and promotes fusion. The term autograft refers to the patient’s own bone, often harvested from the iliac crest. Iliac crest bone graft is a source of both cortical and cancellous bone. Cortical bone provides structural support, while cancellous bone provides a matrix for bony ingrowth. The term allograft refers to sterilized bone from human tissue banks. Allografts also may be cortical, cancellous, or both. Allograft lacks the array of osteoinductive endogenous compounds intrinsic to autograft,
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Surgery_Schwartz. into a solid mass of bone. Arthrodesis must occur in any fused segment to have long-term stability. Failure of arthrodesis results in failed fusion, often in the form of a fibrous nonunion. The rates of successful fusion are higher in the cervical spine than the lum-bar spine. Arthrodesis requires ingrowth of new bone formed by the patient’s osteoblasts across the unstable defect. Insert-ing graft material, such as autograft or allograft, into the defect provides a bridge for osteoblasts and promotes fusion. The term autograft refers to the patient’s own bone, often harvested from the iliac crest. Iliac crest bone graft is a source of both cortical and cancellous bone. Cortical bone provides structural support, while cancellous bone provides a matrix for bony ingrowth. The term allograft refers to sterilized bone from human tissue banks. Allografts also may be cortical, cancellous, or both. Allograft lacks the array of osteoinductive endogenous compounds intrinsic to autograft,
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refers to sterilized bone from human tissue banks. Allografts also may be cortical, cancellous, or both. Allograft lacks the array of osteoinductive endogenous compounds intrinsic to autograft, although supplemental products such as demineralized bone matrix paste can be added to encourage new bone formation. Other techniques for increasing the rates of suc-cessful fusion are being developed, including the integration of osteoinductive bone morphogenetic proteins, known as BMPs, into the fusion constructs.Dynamic stabilization refers to the creation of spinal sta-bility without achieving a bony fusion. The concept applies to both cervical and lumbar motion segments. Artificial lumbar and cervical disc replacement therapies are recent developments in degenerative spine disease that address this concept. How-ever, their use is limited to very select cases. Another motion preservation technique that may hold promise is segmental “soft” stabilization.77 In cases of degenerative
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Surgery_Schwartz. refers to sterilized bone from human tissue banks. Allografts also may be cortical, cancellous, or both. Allograft lacks the array of osteoinductive endogenous compounds intrinsic to autograft, although supplemental products such as demineralized bone matrix paste can be added to encourage new bone formation. Other techniques for increasing the rates of suc-cessful fusion are being developed, including the integration of osteoinductive bone morphogenetic proteins, known as BMPs, into the fusion constructs.Dynamic stabilization refers to the creation of spinal sta-bility without achieving a bony fusion. The concept applies to both cervical and lumbar motion segments. Artificial lumbar and cervical disc replacement therapies are recent developments in degenerative spine disease that address this concept. How-ever, their use is limited to very select cases. Another motion preservation technique that may hold promise is segmental “soft” stabilization.77 In cases of degenerative
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address this concept. How-ever, their use is limited to very select cases. Another motion preservation technique that may hold promise is segmental “soft” stabilization.77 In cases of degenerative spondylolisthe-sis, such systems in the lumbar spine allow for decompressive laminectomy without increasing slippage. In theory, adjacent level facets and discs are spared the stresses of a neighboring bony fusion moment arm.PERIPHERAL NERVECommon pathologic processes that compromise function of the peripheral nervous system include mechanical compression, ischemia, inflammation, and neoplasia.Peripheral Nerve TumorsMost peripheral nerve tumors are benign and grow slowly. Significant pain increases the likelihood that the patient has a malignant tumor. Treatment for peripheral nerve tumors is sur-gical resection to establish diagnosis and evaluate for signs of malignancy. These tumors have various degrees of involvement with the parent nerve. Some can be resected with minimal or no damage to
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Surgery_Schwartz. address this concept. How-ever, their use is limited to very select cases. Another motion preservation technique that may hold promise is segmental “soft” stabilization.77 In cases of degenerative spondylolisthe-sis, such systems in the lumbar spine allow for decompressive laminectomy without increasing slippage. In theory, adjacent level facets and discs are spared the stresses of a neighboring bony fusion moment arm.PERIPHERAL NERVECommon pathologic processes that compromise function of the peripheral nervous system include mechanical compression, ischemia, inflammation, and neoplasia.Peripheral Nerve TumorsMost peripheral nerve tumors are benign and grow slowly. Significant pain increases the likelihood that the patient has a malignant tumor. Treatment for peripheral nerve tumors is sur-gical resection to establish diagnosis and evaluate for signs of malignancy. These tumors have various degrees of involvement with the parent nerve. Some can be resected with minimal or no damage to
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resection to establish diagnosis and evaluate for signs of malignancy. These tumors have various degrees of involvement with the parent nerve. Some can be resected with minimal or no damage to the nerve. Tumors that grow within the nerve often contain functioning fascicles. Total excision of these tumors requires sacrifice of the parent nerve. The choice of subtotal resection, nerve preservation, and observation, vs. total resec-tion with nerve sacrifice depends on tumor histology and the function of the parent nerve.Schwannoma. Schwannomas are the most common peripheral nerve tumors, also referred to as neurilemomas or neurinomas. Most occur in the third decade of life. These benign tumors arise from Schwann cells, which form myelin in peripheral nerves. The most characteristic presentation is a mass lesion with point tenderness and shooting pains on direct palpation. Spontaneous ABBrunicardi_Ch42_p1827-p1878.indd 186601/03/19 7:17 PM 1867NEUROSURGERYCHAPTER 42or continuous pain
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Surgery_Schwartz. resection to establish diagnosis and evaluate for signs of malignancy. These tumors have various degrees of involvement with the parent nerve. Some can be resected with minimal or no damage to the nerve. Tumors that grow within the nerve often contain functioning fascicles. Total excision of these tumors requires sacrifice of the parent nerve. The choice of subtotal resection, nerve preservation, and observation, vs. total resec-tion with nerve sacrifice depends on tumor histology and the function of the parent nerve.Schwannoma. Schwannomas are the most common peripheral nerve tumors, also referred to as neurilemomas or neurinomas. Most occur in the third decade of life. These benign tumors arise from Schwann cells, which form myelin in peripheral nerves. The most characteristic presentation is a mass lesion with point tenderness and shooting pains on direct palpation. Spontaneous ABBrunicardi_Ch42_p1827-p1878.indd 186601/03/19 7:17 PM 1867NEUROSURGERYCHAPTER 42or continuous pain
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is a mass lesion with point tenderness and shooting pains on direct palpation. Spontaneous ABBrunicardi_Ch42_p1827-p1878.indd 186601/03/19 7:17 PM 1867NEUROSURGERYCHAPTER 42or continuous pain suggests malignancy. Schwannomas tend to grow slowly and eccentrically on parent nerves. The eccentric location and discrete encapsulated nature of these tumors often allow total resection without significant damage to the parent nerve. Subtotal resection and observation is reasonable for schwannomas entwined in important nerves, as the incidence of malignant transformation is extremely low.Neurofibroma. Neurofibromas arise within the nerve and tend to be fusiform masses, unlike schwannomas, which tend to grow out of the nerve. Neurofibromas often present as a mass that is tender to palpation. They usually lack the shooting pains char-acteristic of schwannomas. Neurofibromas are often difficult to resect completely without sacrifice of the parent nerve. Neuro-fibromas have a higher incidence
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Surgery_Schwartz. is a mass lesion with point tenderness and shooting pains on direct palpation. Spontaneous ABBrunicardi_Ch42_p1827-p1878.indd 186601/03/19 7:17 PM 1867NEUROSURGERYCHAPTER 42or continuous pain suggests malignancy. Schwannomas tend to grow slowly and eccentrically on parent nerves. The eccentric location and discrete encapsulated nature of these tumors often allow total resection without significant damage to the parent nerve. Subtotal resection and observation is reasonable for schwannomas entwined in important nerves, as the incidence of malignant transformation is extremely low.Neurofibroma. Neurofibromas arise within the nerve and tend to be fusiform masses, unlike schwannomas, which tend to grow out of the nerve. Neurofibromas often present as a mass that is tender to palpation. They usually lack the shooting pains char-acteristic of schwannomas. Neurofibromas are often difficult to resect completely without sacrifice of the parent nerve. Neuro-fibromas have a higher incidence
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usually lack the shooting pains char-acteristic of schwannomas. Neurofibromas are often difficult to resect completely without sacrifice of the parent nerve. Neuro-fibromas have a higher incidence of malignant transformation; therefore, patients with known residual tumors require close observation. Patients with NF1 often have multiple neurofibro-mas. These patients should be offered resection for symptomatic tumors. Risk of malignant degeneration is up to 10%. Malignant neurofibromas have the histologic characteristics of sarcoma.Malignant Nerve Sheath Tumors. Malignant nerve sheath tumors include solitary sarcomas, degenerated neurofibromas, and neuroepitheliomas. Patients with malignant peripheral nerve tumors typically complain of constant pain, rather than pain only on palpation, and are more likely to have motor and sensory deficits in the distribution of the parent nerve. Treat-ment for these tumors is radical excision. This often requires sacrifice of the parent nerve.
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Surgery_Schwartz. usually lack the shooting pains char-acteristic of schwannomas. Neurofibromas are often difficult to resect completely without sacrifice of the parent nerve. Neuro-fibromas have a higher incidence of malignant transformation; therefore, patients with known residual tumors require close observation. Patients with NF1 often have multiple neurofibro-mas. These patients should be offered resection for symptomatic tumors. Risk of malignant degeneration is up to 10%. Malignant neurofibromas have the histologic characteristics of sarcoma.Malignant Nerve Sheath Tumors. Malignant nerve sheath tumors include solitary sarcomas, degenerated neurofibromas, and neuroepitheliomas. Patients with malignant peripheral nerve tumors typically complain of constant pain, rather than pain only on palpation, and are more likely to have motor and sensory deficits in the distribution of the parent nerve. Treat-ment for these tumors is radical excision. This often requires sacrifice of the parent nerve.
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and are more likely to have motor and sensory deficits in the distribution of the parent nerve. Treat-ment for these tumors is radical excision. This often requires sacrifice of the parent nerve. Invasion of nearby soft tissues may occur and necessitate wide resection or amputation in an attempt to prevent systemic metastasis.Entrapment NeuropathiesEntrapment neuropathy presents as neurologic dysfunction in nerves passing through a pathologically small, fixed space. Nerve dysfunction may result directly from chronic, repetitive pressure on the nerve, or from ischemic damage due to impaired perfusion.77 Entrapment causing dysfunction of nerve signaling may be associated with numbness, paresthesias, weakness, or muscle atrophy. The two most common sites of entrapment neu-ropathy are the ulnar nerve at the medial aspect of the elbow and the median nerve at the wrist. Usually EMG/NCS demon-strate slowing across the entrapped segment of nerve. Mechani-cal peripheral nerve disorders
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Surgery_Schwartz. and are more likely to have motor and sensory deficits in the distribution of the parent nerve. Treat-ment for these tumors is radical excision. This often requires sacrifice of the parent nerve. Invasion of nearby soft tissues may occur and necessitate wide resection or amputation in an attempt to prevent systemic metastasis.Entrapment NeuropathiesEntrapment neuropathy presents as neurologic dysfunction in nerves passing through a pathologically small, fixed space. Nerve dysfunction may result directly from chronic, repetitive pressure on the nerve, or from ischemic damage due to impaired perfusion.77 Entrapment causing dysfunction of nerve signaling may be associated with numbness, paresthesias, weakness, or muscle atrophy. The two most common sites of entrapment neu-ropathy are the ulnar nerve at the medial aspect of the elbow and the median nerve at the wrist. Usually EMG/NCS demon-strate slowing across the entrapped segment of nerve. Mechani-cal peripheral nerve disorders
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the ulnar nerve at the medial aspect of the elbow and the median nerve at the wrist. Usually EMG/NCS demon-strate slowing across the entrapped segment of nerve. Mechani-cal peripheral nerve disorders resulting from trauma (brachial plexus disruption, radial nerve damage from humerus fractures, and common peroneal nerve crush injuries) are discussed in the section “Trauma.”Ulnar Neuropathy. The ulnar nerve has contributions from the C7, C8, and T1 nerve roots, arises from the medial cord of the brachial plexus, and supplies most of the intrinsic hand mus-cles (interossei and third and fourth lumbricals) and sensation to the fourth and fifth digits. It passes posteriorly to the medial epicondyle at the elbow in the condylar groove. This segment is superficial and subject to external compression and repeti-tive minor impacts. Patients with ulnar entrapment at the elbow present with numbness and tingling in the medial palm, as well as the fourth and fifth digits. Motor deficits include
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Surgery_Schwartz. the ulnar nerve at the medial aspect of the elbow and the median nerve at the wrist. Usually EMG/NCS demon-strate slowing across the entrapped segment of nerve. Mechani-cal peripheral nerve disorders resulting from trauma (brachial plexus disruption, radial nerve damage from humerus fractures, and common peroneal nerve crush injuries) are discussed in the section “Trauma.”Ulnar Neuropathy. The ulnar nerve has contributions from the C7, C8, and T1 nerve roots, arises from the medial cord of the brachial plexus, and supplies most of the intrinsic hand mus-cles (interossei and third and fourth lumbricals) and sensation to the fourth and fifth digits. It passes posteriorly to the medial epicondyle at the elbow in the condylar groove. This segment is superficial and subject to external compression and repeti-tive minor impacts. Patients with ulnar entrapment at the elbow present with numbness and tingling in the medial palm, as well as the fourth and fifth digits. Motor deficits include
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and repeti-tive minor impacts. Patients with ulnar entrapment at the elbow present with numbness and tingling in the medial palm, as well as the fourth and fifth digits. Motor deficits include weakness and wasting of the intrinsic hand muscles. Treatment for symp-tomatic ulnar entrapment neuropathy is surgical exploration and incision of the fibrous aponeurotic arch that overlies the nerve. A 6-cm curvilinear incision centered between the medial epi-condyle and the olecranon allows exploration of up to 10 cm of nerve and lysis of compressive tissues.Carpal Tunnel Syndrome. The median nerve has contribu-tions from the C5 to T1 nerve roots, arises from the medial and lateral cords of the brachial plexus, and supplies the muscles of wrist and finger flexion and sensation to the palmar aspect of the first, second, and third digits. The median nerve passes through the carpal tunnel in the wrist, lying superficial to the four deep and four superficial flexor tendons. The transverse carpal
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Surgery_Schwartz. and repeti-tive minor impacts. Patients with ulnar entrapment at the elbow present with numbness and tingling in the medial palm, as well as the fourth and fifth digits. Motor deficits include weakness and wasting of the intrinsic hand muscles. Treatment for symp-tomatic ulnar entrapment neuropathy is surgical exploration and incision of the fibrous aponeurotic arch that overlies the nerve. A 6-cm curvilinear incision centered between the medial epi-condyle and the olecranon allows exploration of up to 10 cm of nerve and lysis of compressive tissues.Carpal Tunnel Syndrome. The median nerve has contribu-tions from the C5 to T1 nerve roots, arises from the medial and lateral cords of the brachial plexus, and supplies the muscles of wrist and finger flexion and sensation to the palmar aspect of the first, second, and third digits. The median nerve passes through the carpal tunnel in the wrist, lying superficial to the four deep and four superficial flexor tendons. The transverse carpal
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of the first, second, and third digits. The median nerve passes through the carpal tunnel in the wrist, lying superficial to the four deep and four superficial flexor tendons. The transverse carpal liga-ment is a tough, fibrous band that forms the roof of the carpal tunnel. The ligament attaches to the pisiform and hamate medi-ally and the trapezium and scaphoid laterally. Patients complain of numbness and tingling in the supplied digits, clumsiness, and worsening with sleep or repetitive wrist movement. Patients may notice wasting of the thenar eminence. Treatment for symptomatic carpal tunnel syndrome unresponsive to splinting, analgesics, and rest is surgical division of the flexor retinacu-lum. This often provides prompt relief of pain symptoms and slow recovery of numbness and strength.Autoimmune and Inflammatory DisordersThese are not surgical diseases, but they merit brief mention as they are included in the differential diagnosis for new-onset weakness. Their characteristic
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Surgery_Schwartz. of the first, second, and third digits. The median nerve passes through the carpal tunnel in the wrist, lying superficial to the four deep and four superficial flexor tendons. The transverse carpal liga-ment is a tough, fibrous band that forms the roof of the carpal tunnel. The ligament attaches to the pisiform and hamate medi-ally and the trapezium and scaphoid laterally. Patients complain of numbness and tingling in the supplied digits, clumsiness, and worsening with sleep or repetitive wrist movement. Patients may notice wasting of the thenar eminence. Treatment for symptomatic carpal tunnel syndrome unresponsive to splinting, analgesics, and rest is surgical division of the flexor retinacu-lum. This often provides prompt relief of pain symptoms and slow recovery of numbness and strength.Autoimmune and Inflammatory DisordersThese are not surgical diseases, but they merit brief mention as they are included in the differential diagnosis for new-onset weakness. Their characteristic
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and Inflammatory DisordersThese are not surgical diseases, but they merit brief mention as they are included in the differential diagnosis for new-onset weakness. Their characteristic presentations help distinguish them from weakness due to structural lesions.Guillain-Barré Syndrome. Guillain-Barré syndrome is an acute inflammatory demyelinating polyradiculopathy often occurring after viral infection, surgery, inoculations, or myco-plasma infections. Patients classically present with weakness ascending from the legs to the body, arms, and even cranial nerves. Symptoms usually progress over 2 to 4 weeks and then resolve. Care is supportive. Respiratory weakness may require ventilatory support.Myasthenia Gravis. Myasthenia gravis is an autoimmune process in which antibodies form to the acetylcholine recep-tors of muscles, leading to fluctuating weakness. Most patients have either thymic hyperplasia or thymoma. The most common symptoms are diplopia, ptosis, dysarthria, and dysphagia.
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Surgery_Schwartz. and Inflammatory DisordersThese are not surgical diseases, but they merit brief mention as they are included in the differential diagnosis for new-onset weakness. Their characteristic presentations help distinguish them from weakness due to structural lesions.Guillain-Barré Syndrome. Guillain-Barré syndrome is an acute inflammatory demyelinating polyradiculopathy often occurring after viral infection, surgery, inoculations, or myco-plasma infections. Patients classically present with weakness ascending from the legs to the body, arms, and even cranial nerves. Symptoms usually progress over 2 to 4 weeks and then resolve. Care is supportive. Respiratory weakness may require ventilatory support.Myasthenia Gravis. Myasthenia gravis is an autoimmune process in which antibodies form to the acetylcholine recep-tors of muscles, leading to fluctuating weakness. Most patients have either thymic hyperplasia or thymoma. The most common symptoms are diplopia, ptosis, dysarthria, and dysphagia.
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recep-tors of muscles, leading to fluctuating weakness. Most patients have either thymic hyperplasia or thymoma. The most common symptoms are diplopia, ptosis, dysarthria, and dysphagia. More severe cases have limb or respiratory involvement. Weakness worsens with repetitive movement. Treatment is with acetylcho-linesterase inhibitors and possible thymectomy.Eaton-Lambert Syndrome. Eaton-Lambert syndrome is an autoimmune process with antibodies to the presynaptic calcium channels. This is a paraneoplastic syndrome most commonly associated with oat cell carcinoma. Patients have weakness of proximal limb muscles that improves with repetitive movement. This diagnosis must prompt oncologic evaluation.INFECTIONCNS infections of interest to neurosurgeons include those that cause focal neurologic deficit due to mass effect, require surgi-cal aspiration or drainage because antibiotic therapy alone is insufficient, cause mechanical instability of the spine, or occur after neurosurgical
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Surgery_Schwartz. recep-tors of muscles, leading to fluctuating weakness. Most patients have either thymic hyperplasia or thymoma. The most common symptoms are diplopia, ptosis, dysarthria, and dysphagia. More severe cases have limb or respiratory involvement. Weakness worsens with repetitive movement. Treatment is with acetylcho-linesterase inhibitors and possible thymectomy.Eaton-Lambert Syndrome. Eaton-Lambert syndrome is an autoimmune process with antibodies to the presynaptic calcium channels. This is a paraneoplastic syndrome most commonly associated with oat cell carcinoma. Patients have weakness of proximal limb muscles that improves with repetitive movement. This diagnosis must prompt oncologic evaluation.INFECTIONCNS infections of interest to neurosurgeons include those that cause focal neurologic deficit due to mass effect, require surgi-cal aspiration or drainage because antibiotic therapy alone is insufficient, cause mechanical instability of the spine, or occur after neurosurgical
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deficit due to mass effect, require surgi-cal aspiration or drainage because antibiotic therapy alone is insufficient, cause mechanical instability of the spine, or occur after neurosurgical procedures.CranialOsteomyelitis. The skull is highly vascular and resistant to infections. Osteomyelitis of the skull may develop by contigu-ous spread from pyogenic sinus disease or from contamination by penetrating trauma. Staphylococcus aureus and S epidermidis are the most frequent causative organisms. Patients usually present with redness, swelling, and pain. Contrast head CT aids 7Brunicardi_Ch42_p1827-p1878.indd 186701/03/19 7:17 PM 1868SPECIFIC CONSIDERATIONSPART IIdiagnosis and shows the extent of involved bone, along with associated abscesses or empyema. Osteomyelitis treatment entails surgical debridement of involved bone followed by 2 to 4 months of antibiotics. Craniotomy wound infections are a special concern because performing a craniotomy creates a devascularized free bone
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Surgery_Schwartz. deficit due to mass effect, require surgi-cal aspiration or drainage because antibiotic therapy alone is insufficient, cause mechanical instability of the spine, or occur after neurosurgical procedures.CranialOsteomyelitis. The skull is highly vascular and resistant to infections. Osteomyelitis of the skull may develop by contigu-ous spread from pyogenic sinus disease or from contamination by penetrating trauma. Staphylococcus aureus and S epidermidis are the most frequent causative organisms. Patients usually present with redness, swelling, and pain. Contrast head CT aids 7Brunicardi_Ch42_p1827-p1878.indd 186701/03/19 7:17 PM 1868SPECIFIC CONSIDERATIONSPART IIdiagnosis and shows the extent of involved bone, along with associated abscesses or empyema. Osteomyelitis treatment entails surgical debridement of involved bone followed by 2 to 4 months of antibiotics. Craniotomy wound infections are a special concern because performing a craniotomy creates a devascularized free bone
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surgical debridement of involved bone followed by 2 to 4 months of antibiotics. Craniotomy wound infections are a special concern because performing a craniotomy creates a devascularized free bone flap susceptible to infection and not penetrated by antibiotics. These wounds must be debrided and the bone flaps removed and discarded. Subsequent care involves appropriate antibiotic therapy, observation for signs of recurrent infection off antibiotics, and return to the OR for titanium or methylmethacrylate cranioplasty 6 to 12 months later.Subdural Empyema. Subdural empyema is a rapidly progres-sive pyogenic infection. The subdural space lacks significant barriers to the spread of the infection, such as compartmental-ization or septations. Subdural empyemas usually occur over the cerebral convexities. Potential infectious sources include sinus disease, penetrating trauma, and otitis. Streptococci and staphylococci are the most frequent sources. Presenting symp-toms include fever,
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Surgery_Schwartz. surgical debridement of involved bone followed by 2 to 4 months of antibiotics. Craniotomy wound infections are a special concern because performing a craniotomy creates a devascularized free bone flap susceptible to infection and not penetrated by antibiotics. These wounds must be debrided and the bone flaps removed and discarded. Subsequent care involves appropriate antibiotic therapy, observation for signs of recurrent infection off antibiotics, and return to the OR for titanium or methylmethacrylate cranioplasty 6 to 12 months later.Subdural Empyema. Subdural empyema is a rapidly progres-sive pyogenic infection. The subdural space lacks significant barriers to the spread of the infection, such as compartmental-ization or septations. Subdural empyemas usually occur over the cerebral convexities. Potential infectious sources include sinus disease, penetrating trauma, and otitis. Streptococci and staphylococci are the most frequent sources. Presenting symp-toms include fever,
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convexities. Potential infectious sources include sinus disease, penetrating trauma, and otitis. Streptococci and staphylococci are the most frequent sources. Presenting symp-toms include fever, headache, neck stiffness, seizures, or focal neurologic deficit. Neurologic deficit results from inflammation of cortical blood vessels, leading to thrombosis and stroke. The most common deficit is contralateral hemiparesis. Patients with suggestive symptoms should undergo rapid contrast CT scan. LP frequently fails to yield the offending organism and risks herniation due to mass effect. Typical treatment is wide hemi-craniectomy, dural opening, and lavage. The pus may be thick or septated, making burr hole drainage or small craniotomy insufficient. Patients then require 1 to 2 months of antibiotics. Subdural empyema has 10% to 20% mortality risk and common chronic sequelae, including development of a seizure disorder and residual hemiparesis. However, many patients do make a good
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Surgery_Schwartz. convexities. Potential infectious sources include sinus disease, penetrating trauma, and otitis. Streptococci and staphylococci are the most frequent sources. Presenting symp-toms include fever, headache, neck stiffness, seizures, or focal neurologic deficit. Neurologic deficit results from inflammation of cortical blood vessels, leading to thrombosis and stroke. The most common deficit is contralateral hemiparesis. Patients with suggestive symptoms should undergo rapid contrast CT scan. LP frequently fails to yield the offending organism and risks herniation due to mass effect. Typical treatment is wide hemi-craniectomy, dural opening, and lavage. The pus may be thick or septated, making burr hole drainage or small craniotomy insufficient. Patients then require 1 to 2 months of antibiotics. Subdural empyema has 10% to 20% mortality risk and common chronic sequelae, including development of a seizure disorder and residual hemiparesis. However, many patients do make a good
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of antibiotics. Subdural empyema has 10% to 20% mortality risk and common chronic sequelae, including development of a seizure disorder and residual hemiparesis. However, many patients do make a good recovery.Brain Abscess. Brain abscess is encapsulated infection within the brain parenchyma. It may spread hematogenously in patients with endocarditis or intracardiac or intrapulmonary right-to-left shunts, by migration from the sinuses or ear, or via direct seed-ing by penetrating trauma. Disorganized cerebritis often pre-cedes formation of the organized, walled-off abscess. Patients may present with nonspecific symptoms such as headache, nau-sea, or lethargy, or with focal neurologic deficit such as hemi-paresis. Alternatively, patients may present in extremis if the abscess ruptures into the ventricular system. Abscesses appear as well-demarcated, ring-enhancing, thin-walled lesions on CT scan and MRI, and often have associated edema and mass effect. Patients require antibiotic
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Surgery_Schwartz. of antibiotics. Subdural empyema has 10% to 20% mortality risk and common chronic sequelae, including development of a seizure disorder and residual hemiparesis. However, many patients do make a good recovery.Brain Abscess. Brain abscess is encapsulated infection within the brain parenchyma. It may spread hematogenously in patients with endocarditis or intracardiac or intrapulmonary right-to-left shunts, by migration from the sinuses or ear, or via direct seed-ing by penetrating trauma. Disorganized cerebritis often pre-cedes formation of the organized, walled-off abscess. Patients may present with nonspecific symptoms such as headache, nau-sea, or lethargy, or with focal neurologic deficit such as hemi-paresis. Alternatively, patients may present in extremis if the abscess ruptures into the ventricular system. Abscesses appear as well-demarcated, ring-enhancing, thin-walled lesions on CT scan and MRI, and often have associated edema and mass effect. Patients require antibiotic
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into the ventricular system. Abscesses appear as well-demarcated, ring-enhancing, thin-walled lesions on CT scan and MRI, and often have associated edema and mass effect. Patients require antibiotic therapy after needle aspira-tion or surgical evacuation. Antibiotic therapy without surgical evacuation may be considered for patients with small, multiple, or critically located abscesses. Abscesses that are large, cause mass effect, decreased mental status, or that fail to decrease in size after 1 week of antibiotics, should be evacuated. Nonsurgical management still requires aspiration or biopsy specimen for organism culture and sensitivities. Blood and CSF cultures rarely give definitive diagnosis. Removal of an encapsulated abscess significantly shortens the length of antibiotic therapy required to eliminate all organisms. Common chronic sequelae after suc-cessful treatment include seizures or focal neurologic deficit.SpinePyogenic Vertebral Osteomyelitis. Pyogenic vertebral
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Surgery_Schwartz. into the ventricular system. Abscesses appear as well-demarcated, ring-enhancing, thin-walled lesions on CT scan and MRI, and often have associated edema and mass effect. Patients require antibiotic therapy after needle aspira-tion or surgical evacuation. Antibiotic therapy without surgical evacuation may be considered for patients with small, multiple, or critically located abscesses. Abscesses that are large, cause mass effect, decreased mental status, or that fail to decrease in size after 1 week of antibiotics, should be evacuated. Nonsurgical management still requires aspiration or biopsy specimen for organism culture and sensitivities. Blood and CSF cultures rarely give definitive diagnosis. Removal of an encapsulated abscess significantly shortens the length of antibiotic therapy required to eliminate all organisms. Common chronic sequelae after suc-cessful treatment include seizures or focal neurologic deficit.SpinePyogenic Vertebral Osteomyelitis. Pyogenic vertebral
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therapy required to eliminate all organisms. Common chronic sequelae after suc-cessful treatment include seizures or focal neurologic deficit.SpinePyogenic Vertebral Osteomyelitis. Pyogenic vertebral osteomyelitis is a destructive bacterial infection of the vertebrae, usually of the vertebral body. Vertebral osteomyelitis frequently results from hematogenous spread of distant disease, but may occur as an extension of adjacent disease, such as psoas abscess or perinephric abscess. S aureus and Enterobacter spp. are the most frequent etiologic organisms. Patients usually present with fever and back pain. Diabetics, IV drug abusers, and dialysis patients have increased incidence of vertebral osteomyelitis. Epidural extension may lead to compression of the spinal cord or nerve roots with resultant neurologic deficit. Osteomyelitis presents a lytic picture on imaging and must be distinguished from neoplastic disease. Adjacent intervertebral disc involve-ment occurs frequently with pyogenic
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Surgery_Schwartz. therapy required to eliminate all organisms. Common chronic sequelae after suc-cessful treatment include seizures or focal neurologic deficit.SpinePyogenic Vertebral Osteomyelitis. Pyogenic vertebral osteomyelitis is a destructive bacterial infection of the vertebrae, usually of the vertebral body. Vertebral osteomyelitis frequently results from hematogenous spread of distant disease, but may occur as an extension of adjacent disease, such as psoas abscess or perinephric abscess. S aureus and Enterobacter spp. are the most frequent etiologic organisms. Patients usually present with fever and back pain. Diabetics, IV drug abusers, and dialysis patients have increased incidence of vertebral osteomyelitis. Epidural extension may lead to compression of the spinal cord or nerve roots with resultant neurologic deficit. Osteomyelitis presents a lytic picture on imaging and must be distinguished from neoplastic disease. Adjacent intervertebral disc involve-ment occurs frequently with pyogenic
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neurologic deficit. Osteomyelitis presents a lytic picture on imaging and must be distinguished from neoplastic disease. Adjacent intervertebral disc involve-ment occurs frequently with pyogenic osteomyelitis, but rarely with neoplasia. Plain films and CT help assess the extent of bony destruction or deformity such as kyphosis. MRI shows adjacent soft tissue or epidural disease. Most cases can be treated suc-cessfully with antibiotics alone, although the organism must be isolated to steer antibiotic choice. Blood cultures may be positive. Surgical intervention may be required for debridement when antibiotics alone fail, or for stabilization and fusion in the setting of instability and deformity.Tuberculous Vertebral Osteomyelitis. Tuberculous verte-bral osteomyelitis, also known as Pott’s disease, occurs most commonly in underdeveloped countries and in the immuno-compromised. Several features differentiate tuberculous osteo-myelitis from bacterial osteomyelitis. The infection is
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Surgery_Schwartz. neurologic deficit. Osteomyelitis presents a lytic picture on imaging and must be distinguished from neoplastic disease. Adjacent intervertebral disc involve-ment occurs frequently with pyogenic osteomyelitis, but rarely with neoplasia. Plain films and CT help assess the extent of bony destruction or deformity such as kyphosis. MRI shows adjacent soft tissue or epidural disease. Most cases can be treated suc-cessfully with antibiotics alone, although the organism must be isolated to steer antibiotic choice. Blood cultures may be positive. Surgical intervention may be required for debridement when antibiotics alone fail, or for stabilization and fusion in the setting of instability and deformity.Tuberculous Vertebral Osteomyelitis. Tuberculous verte-bral osteomyelitis, also known as Pott’s disease, occurs most commonly in underdeveloped countries and in the immuno-compromised. Several features differentiate tuberculous osteo-myelitis from bacterial osteomyelitis. The infection is
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disease, occurs most commonly in underdeveloped countries and in the immuno-compromised. Several features differentiate tuberculous osteo-myelitis from bacterial osteomyelitis. The infection is indolent and symptoms often progress slowly over months. Tuberculosis rarely involves the intervertebral disc. The involved bodies may have sclerotic rather than lytic changes. Multiple nonadjacent vertebrae may be involved. The upper lumbar and lower tho-racic vertebrae are most commonly affected. Diagnosis requires documentation of acid-fast bacilli. Treatment involves long-term antimycobacterial drugs. Patients with spinal instability or neural compression from epidural inflammatory tissue should undergo debridement and fusion as needed.Discitis. Primary infection of the intervertebral disc space, or discitis, is most commonly secondary to postoperative infec-tions. Spontaneous discitis occurs more commonly in children. S aureus and S epidermidis account for most cases. The pri-mary symptom
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Surgery_Schwartz. disease, occurs most commonly in underdeveloped countries and in the immuno-compromised. Several features differentiate tuberculous osteo-myelitis from bacterial osteomyelitis. The infection is indolent and symptoms often progress slowly over months. Tuberculosis rarely involves the intervertebral disc. The involved bodies may have sclerotic rather than lytic changes. Multiple nonadjacent vertebrae may be involved. The upper lumbar and lower tho-racic vertebrae are most commonly affected. Diagnosis requires documentation of acid-fast bacilli. Treatment involves long-term antimycobacterial drugs. Patients with spinal instability or neural compression from epidural inflammatory tissue should undergo debridement and fusion as needed.Discitis. Primary infection of the intervertebral disc space, or discitis, is most commonly secondary to postoperative infec-tions. Spontaneous discitis occurs more commonly in children. S aureus and S epidermidis account for most cases. The pri-mary symptom
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or discitis, is most commonly secondary to postoperative infec-tions. Spontaneous discitis occurs more commonly in children. S aureus and S epidermidis account for most cases. The pri-mary symptom is back pain. Other signs and symptoms include radicular pain, fevers, paraspinal muscle spasm, and localized tenderness to palpation. Many cases will resolve without anti-biotics, which generally are given for positive blood or biopsy specimen cultures or persistent constitutional symptoms. Most patients will have spontaneous fusion across the involved disc and do not need debridement or fusion.Epidural Abscess. Epidural abscesses may arise from or spread to the adjacent bone or disc, so distinguishing between vertebral osteomyelitis or discitis and a spinal epidural abscess may be difficult. The most common presenting signs and symp-toms are back pain, fever, and tenderness to palpation of the spine. The most significant risk of epidural abscess is weakness progressing to paralysis due to
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Surgery_Schwartz. or discitis, is most commonly secondary to postoperative infec-tions. Spontaneous discitis occurs more commonly in children. S aureus and S epidermidis account for most cases. The pri-mary symptom is back pain. Other signs and symptoms include radicular pain, fevers, paraspinal muscle spasm, and localized tenderness to palpation. Many cases will resolve without anti-biotics, which generally are given for positive blood or biopsy specimen cultures or persistent constitutional symptoms. Most patients will have spontaneous fusion across the involved disc and do not need debridement or fusion.Epidural Abscess. Epidural abscesses may arise from or spread to the adjacent bone or disc, so distinguishing between vertebral osteomyelitis or discitis and a spinal epidural abscess may be difficult. The most common presenting signs and symp-toms are back pain, fever, and tenderness to palpation of the spine. The most significant risk of epidural abscess is weakness progressing to paralysis due to
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most common presenting signs and symp-toms are back pain, fever, and tenderness to palpation of the spine. The most significant risk of epidural abscess is weakness progressing to paralysis due to spinal cord or nerve root dam-age. Cord and root damage may be due to direct compression or to inflammatory thrombosis resulting in venous infarction. S aureus and Streptococcus spp. are the most common organisms. Methicillin-resistant S aureus now constitutes a significant pro-portion of these infections, as high as 40%.78 The source may be hematogenous spread, local extension, or operative contamina-tion. MRI best demonstrates the epidural space and degree of neural compromise. Patients with spinal epidural abscess and neurologic compromise should undergo surgical debridement for decompression and diagnosis, followed by culture-directed Brunicardi_Ch42_p1827-p1878.indd 186801/03/19 7:17 PM 1869NEUROSURGERYCHAPTER 42antibiotic therapy. Relative contraindications to surgery include
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Surgery_Schwartz. most common presenting signs and symp-toms are back pain, fever, and tenderness to palpation of the spine. The most significant risk of epidural abscess is weakness progressing to paralysis due to spinal cord or nerve root dam-age. Cord and root damage may be due to direct compression or to inflammatory thrombosis resulting in venous infarction. S aureus and Streptococcus spp. are the most common organisms. Methicillin-resistant S aureus now constitutes a significant pro-portion of these infections, as high as 40%.78 The source may be hematogenous spread, local extension, or operative contamina-tion. MRI best demonstrates the epidural space and degree of neural compromise. Patients with spinal epidural abscess and neurologic compromise should undergo surgical debridement for decompression and diagnosis, followed by culture-directed Brunicardi_Ch42_p1827-p1878.indd 186801/03/19 7:17 PM 1869NEUROSURGERYCHAPTER 42antibiotic therapy. Relative contraindications to surgery include
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and diagnosis, followed by culture-directed Brunicardi_Ch42_p1827-p1878.indd 186801/03/19 7:17 PM 1869NEUROSURGERYCHAPTER 42antibiotic therapy. Relative contraindications to surgery include prohibitive comorbidities or total lack of neurologic function below the involved level. Patients with no neurologic deficits and an identified organism may be treated with antibiotics alone and very close observation. However, this management strat-egy remains somewhat controversial because these patients can undergo rapid and irreversible neurologic decline. Most epidural abscesses can be accessed via laminectomy without fusion. Col-lections predominantly anterior to the cervical or thoracic cord may require anterior approach and fusion.FUNCTIONAL NEUROSURGERYEpilepsy SurgerySeizures result from uncontrolled neuronal electrical activity. Seizures may result from irritative lesions in the brain, such as tumors or hematomas, or from physiologic or structural abnor-malities. Seizures may involve
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Surgery_Schwartz. and diagnosis, followed by culture-directed Brunicardi_Ch42_p1827-p1878.indd 186801/03/19 7:17 PM 1869NEUROSURGERYCHAPTER 42antibiotic therapy. Relative contraindications to surgery include prohibitive comorbidities or total lack of neurologic function below the involved level. Patients with no neurologic deficits and an identified organism may be treated with antibiotics alone and very close observation. However, this management strat-egy remains somewhat controversial because these patients can undergo rapid and irreversible neurologic decline. Most epidural abscesses can be accessed via laminectomy without fusion. Col-lections predominantly anterior to the cervical or thoracic cord may require anterior approach and fusion.FUNCTIONAL NEUROSURGERYEpilepsy SurgerySeizures result from uncontrolled neuronal electrical activity. Seizures may result from irritative lesions in the brain, such as tumors or hematomas, or from physiologic or structural abnor-malities. Seizures may involve
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neuronal electrical activity. Seizures may result from irritative lesions in the brain, such as tumors or hematomas, or from physiologic or structural abnor-malities. Seizures may involve a part of the brain (focal) or the entire brain (generalized). Focal seizures may be associated with normal consciousness (simple) or decreased conscious-ness (complex). All generalized seizures cause loss of con-sciousness. Focal seizures may secondarily generalize. Patients with multiple unprovoked seizures over time are considered to have epilepsy. The type of epilepsy depends on such factors as type of seizures, electroencephalographic (EEG) findings, associated syndromes, and identifiable etiologies. All patients with unexplained seizures (i.e., no obvious cause such as head trauma or alcohol withdrawal) require thorough neurologic evaluation, including imaging to evaluate for a mass lesion. Antiepileptic drugs (AEDs) form the first line of therapy for epilepsy, initially as monotherapy, then as
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Surgery_Schwartz. neuronal electrical activity. Seizures may result from irritative lesions in the brain, such as tumors or hematomas, or from physiologic or structural abnor-malities. Seizures may involve a part of the brain (focal) or the entire brain (generalized). Focal seizures may be associated with normal consciousness (simple) or decreased conscious-ness (complex). All generalized seizures cause loss of con-sciousness. Focal seizures may secondarily generalize. Patients with multiple unprovoked seizures over time are considered to have epilepsy. The type of epilepsy depends on such factors as type of seizures, electroencephalographic (EEG) findings, associated syndromes, and identifiable etiologies. All patients with unexplained seizures (i.e., no obvious cause such as head trauma or alcohol withdrawal) require thorough neurologic evaluation, including imaging to evaluate for a mass lesion. Antiepileptic drugs (AEDs) form the first line of therapy for epilepsy, initially as monotherapy, then as
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require thorough neurologic evaluation, including imaging to evaluate for a mass lesion. Antiepileptic drugs (AEDs) form the first line of therapy for epilepsy, initially as monotherapy, then as combination ther-apy. Epilepsy patients who have failed satisfactory trials of sev-eral AED combination regimens may be candidates for surgical intervention. Lack of seizure control or patient intolerance of the medications may constitute failure. Epilepsy surgery can decrease the frequency of seizures by resection of the electrical source of the seizures, or decrease the severity of seizures by disconnecting white matter tracts through which the abnormal electrical activity spreads. Four types of epilepsy surgery are discussed in sections that follow. Epilepsy surgery appears to be extremely underused, given the relatively low risk of the procedures, and the crippling social and economic effects of uncontrolled or partially controlled epilepsy.79 Patients with symptoms, imaging abnormalities,
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Surgery_Schwartz. require thorough neurologic evaluation, including imaging to evaluate for a mass lesion. Antiepileptic drugs (AEDs) form the first line of therapy for epilepsy, initially as monotherapy, then as combination ther-apy. Epilepsy patients who have failed satisfactory trials of sev-eral AED combination regimens may be candidates for surgical intervention. Lack of seizure control or patient intolerance of the medications may constitute failure. Epilepsy surgery can decrease the frequency of seizures by resection of the electrical source of the seizures, or decrease the severity of seizures by disconnecting white matter tracts through which the abnormal electrical activity spreads. Four types of epilepsy surgery are discussed in sections that follow. Epilepsy surgery appears to be extremely underused, given the relatively low risk of the procedures, and the crippling social and economic effects of uncontrolled or partially controlled epilepsy.79 Patients with symptoms, imaging abnormalities,
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given the relatively low risk of the procedures, and the crippling social and economic effects of uncontrolled or partially controlled epilepsy.79 Patients with symptoms, imaging abnormalities, and EEG analysis compat-ible with a specific seizure focus are most likely to have good results from epilepsy surgery.Anterior Temporal Lobectomy. Medial temporal lobe struc-tural abnormalities can lead to complex partial seizures (CPS). Many patients with CPS have poor seizure control on medi-cations. Patients with CPS may have significant reduction in seizure frequency or cessation of seizures after resection of the anterior temporal lobe. The amygdala and the head of the hip-pocampus are removed as part of the lobectomy. Resection may be taken back approximately 4.5 cm from the temporal tip in the language-dominant hemisphere, and 6 cm from the temporal tip in the language nondominant hemisphere, with low risk of significant neurologic deficits.80 The two main risks of anterior temporal
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Surgery_Schwartz. given the relatively low risk of the procedures, and the crippling social and economic effects of uncontrolled or partially controlled epilepsy.79 Patients with symptoms, imaging abnormalities, and EEG analysis compat-ible with a specific seizure focus are most likely to have good results from epilepsy surgery.Anterior Temporal Lobectomy. Medial temporal lobe struc-tural abnormalities can lead to complex partial seizures (CPS). Many patients with CPS have poor seizure control on medi-cations. Patients with CPS may have significant reduction in seizure frequency or cessation of seizures after resection of the anterior temporal lobe. The amygdala and the head of the hip-pocampus are removed as part of the lobectomy. Resection may be taken back approximately 4.5 cm from the temporal tip in the language-dominant hemisphere, and 6 cm from the temporal tip in the language nondominant hemisphere, with low risk of significant neurologic deficits.80 The two main risks of anterior temporal
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in the language-dominant hemisphere, and 6 cm from the temporal tip in the language nondominant hemisphere, with low risk of significant neurologic deficits.80 The two main risks of anterior temporal lobectomy are memory impairment and visual loss. Removal of the hippocampus in a patient with an atrophied or nonfunctional contralateral hippocampus causes a global mem-ory deficit. Interruption of the optic radiations, which carry visual signals from the contralateral superior visual quadrants of both eyes, causes a contralateral superior quadrantanopia, known as a pie in the sky field cut.Corpus Callosotomy. Patients with generalized seizures, atonic seizures associated with drop attacks, or absence sei-zures, who are found to have bilaterally coordinated patho-logic cortical discharges on EEG and who fail AED therapy, may be candidates for corpus callosotomy. The corpus cal-losum is a large white matter tract that connects the cerebral hemispheres. Loss of consciousness requires
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Surgery_Schwartz. in the language-dominant hemisphere, and 6 cm from the temporal tip in the language nondominant hemisphere, with low risk of significant neurologic deficits.80 The two main risks of anterior temporal lobectomy are memory impairment and visual loss. Removal of the hippocampus in a patient with an atrophied or nonfunctional contralateral hippocampus causes a global mem-ory deficit. Interruption of the optic radiations, which carry visual signals from the contralateral superior visual quadrants of both eyes, causes a contralateral superior quadrantanopia, known as a pie in the sky field cut.Corpus Callosotomy. Patients with generalized seizures, atonic seizures associated with drop attacks, or absence sei-zures, who are found to have bilaterally coordinated patho-logic cortical discharges on EEG and who fail AED therapy, may be candidates for corpus callosotomy. The corpus cal-losum is a large white matter tract that connects the cerebral hemispheres. Loss of consciousness requires
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on EEG and who fail AED therapy, may be candidates for corpus callosotomy. The corpus cal-losum is a large white matter tract that connects the cerebral hemispheres. Loss of consciousness requires simultaneous seizure activity in both hemispheres. Focal or partial seizures may spread via the corpus callosum to the contralateral hemi-sphere, causing generalization and loss of consciousness. Divi-sion of the corpus callosum can interrupt this spread. Patients may have decreased numbers of seizures and/or fewer epi-sodes of lost consciousness. Usually only the anterior half or two-thirds of the corpus callosum is divided, as more extensive division increases the risk of disconnection syndrome. Patients with disconnection syndrome are unable to match objects in the opposite visual hemifields, to identify objects held in one hand with the other hemifield, and to write with the left hand or name objects held in the left hand (in left hemisphere–dominant patients).Hemispherectomy. Children
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Surgery_Schwartz. on EEG and who fail AED therapy, may be candidates for corpus callosotomy. The corpus cal-losum is a large white matter tract that connects the cerebral hemispheres. Loss of consciousness requires simultaneous seizure activity in both hemispheres. Focal or partial seizures may spread via the corpus callosum to the contralateral hemi-sphere, causing generalization and loss of consciousness. Divi-sion of the corpus callosum can interrupt this spread. Patients may have decreased numbers of seizures and/or fewer epi-sodes of lost consciousness. Usually only the anterior half or two-thirds of the corpus callosum is divided, as more extensive division increases the risk of disconnection syndrome. Patients with disconnection syndrome are unable to match objects in the opposite visual hemifields, to identify objects held in one hand with the other hemifield, and to write with the left hand or name objects held in the left hand (in left hemisphere–dominant patients).Hemispherectomy. Children
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to identify objects held in one hand with the other hemifield, and to write with the left hand or name objects held in the left hand (in left hemisphere–dominant patients).Hemispherectomy. Children with intractable epilepsy, struc-tural anomalies in one hemisphere, and contralateral hemiple-gia, may have improved seizure control after resection of the hemisphere (anatomic hemispherectomy) or disruption of all connections to the hemisphere (functional hemispherectomy). Functional hemispherectomy often is preferred over anatomic hemispherectomy because of the high incidence of complica-tions such as hematoma formation and ventriculoperitoneal shunt dependence associated with the latter.Vagus Nerve Stimulation. Neuromodulatory treatments like vagus nerve stimulation (VNS), approved by the U.S. Food and Drug Administration (FDA) in 1997, are less invasive and offer some titratability in addition to reversibility unlike the resec-tive surgical options previously described. Since first
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Surgery_Schwartz. to identify objects held in one hand with the other hemifield, and to write with the left hand or name objects held in the left hand (in left hemisphere–dominant patients).Hemispherectomy. Children with intractable epilepsy, struc-tural anomalies in one hemisphere, and contralateral hemiple-gia, may have improved seizure control after resection of the hemisphere (anatomic hemispherectomy) or disruption of all connections to the hemisphere (functional hemispherectomy). Functional hemispherectomy often is preferred over anatomic hemispherectomy because of the high incidence of complica-tions such as hematoma formation and ventriculoperitoneal shunt dependence associated with the latter.Vagus Nerve Stimulation. Neuromodulatory treatments like vagus nerve stimulation (VNS), approved by the U.S. Food and Drug Administration (FDA) in 1997, are less invasive and offer some titratability in addition to reversibility unlike the resec-tive surgical options previously described. Since first
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U.S. Food and Drug Administration (FDA) in 1997, are less invasive and offer some titratability in addition to reversibility unlike the resec-tive surgical options previously described. Since first reported in 1985, VNS has proven to be efficacious in certain patient populations for several disorders such as treatment-resistant major depressive disorder, bipolar disorder, and epilepsy. In VNS, a pulse generator is placed under the skin in the chest and is connected to the vagus nerve by an electrical lead. Chronic, intermittent VNS has been proven to be an effective option for patients suffering from medically refractory seizures who are not candidates for surgical resection. Although only a small minority of patients will be entirely seizure-free, three blinded, randomized-controlled trials have examined VNS and demon-strated significant clinical improvement compared to sham.81-83 Generally VNS is well-tolerated and safe, as device implantation is associated with a low rate of
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Surgery_Schwartz. U.S. Food and Drug Administration (FDA) in 1997, are less invasive and offer some titratability in addition to reversibility unlike the resec-tive surgical options previously described. Since first reported in 1985, VNS has proven to be efficacious in certain patient populations for several disorders such as treatment-resistant major depressive disorder, bipolar disorder, and epilepsy. In VNS, a pulse generator is placed under the skin in the chest and is connected to the vagus nerve by an electrical lead. Chronic, intermittent VNS has been proven to be an effective option for patients suffering from medically refractory seizures who are not candidates for surgical resection. Although only a small minority of patients will be entirely seizure-free, three blinded, randomized-controlled trials have examined VNS and demon-strated significant clinical improvement compared to sham.81-83 Generally VNS is well-tolerated and safe, as device implantation is associated with a low rate of
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trials have examined VNS and demon-strated significant clinical improvement compared to sham.81-83 Generally VNS is well-tolerated and safe, as device implantation is associated with a low rate of perioperative complications. Addi-tionally, the majority of side effects are stimulation-dependent and thus, reversible. For the most part, VNS is limited in its appli-cation because it can only exert its effects by altering neural activ-ity via the vagus nerve. Procedures with brain region-specificity are being investigated.Deep Brain StimulationThe following summary of deep brain stimulation (DBS) will include a review of the current FDA-approved indications, as well the expanding applications of this therapy, currently being investigated preclinically and in clinical trials. While the Brunicardi_Ch42_p1827-p1878.indd 186901/03/19 7:17 PM 1870SPECIFIC CONSIDERATIONSPART IImechanism of action of DBS continues to elude our understand-ing, it is well established that administering
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Surgery_Schwartz. trials have examined VNS and demon-strated significant clinical improvement compared to sham.81-83 Generally VNS is well-tolerated and safe, as device implantation is associated with a low rate of perioperative complications. Addi-tionally, the majority of side effects are stimulation-dependent and thus, reversible. For the most part, VNS is limited in its appli-cation because it can only exert its effects by altering neural activ-ity via the vagus nerve. Procedures with brain region-specificity are being investigated.Deep Brain StimulationThe following summary of deep brain stimulation (DBS) will include a review of the current FDA-approved indications, as well the expanding applications of this therapy, currently being investigated preclinically and in clinical trials. While the Brunicardi_Ch42_p1827-p1878.indd 186901/03/19 7:17 PM 1870SPECIFIC CONSIDERATIONSPART IImechanism of action of DBS continues to elude our understand-ing, it is well established that administering
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Brunicardi_Ch42_p1827-p1878.indd 186901/03/19 7:17 PM 1870SPECIFIC CONSIDERATIONSPART IImechanism of action of DBS continues to elude our understand-ing, it is well established that administering electrical stimula-tion to a nucleus in the brain known to be involved in a given disease can disrupt the pathologic signals emanating to or from this brain region. A fine electrical lead is placed in a deep brain nucleus and connected to pulse generators placed in the chest in a manner similar to cardiac pacemakers. Connector wires travel from the generators in the subcutaneous space up the neck and in the subgaleal space in the head, to connect the pulse gen-erators to the electrical leads. Proper lead placement is accom-plished with stereotactic guidance. A frame is rigidly fixed to the patient’s head, and an MRI is obtained with the frame in place. Calculation of the coordinates of the millimeter-sized deep brain nuclei is performed in relation to the three-dimensional space defined
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Surgery_Schwartz. Brunicardi_Ch42_p1827-p1878.indd 186901/03/19 7:17 PM 1870SPECIFIC CONSIDERATIONSPART IImechanism of action of DBS continues to elude our understand-ing, it is well established that administering electrical stimula-tion to a nucleus in the brain known to be involved in a given disease can disrupt the pathologic signals emanating to or from this brain region. A fine electrical lead is placed in a deep brain nucleus and connected to pulse generators placed in the chest in a manner similar to cardiac pacemakers. Connector wires travel from the generators in the subcutaneous space up the neck and in the subgaleal space in the head, to connect the pulse gen-erators to the electrical leads. Proper lead placement is accom-plished with stereotactic guidance. A frame is rigidly fixed to the patient’s head, and an MRI is obtained with the frame in place. Calculation of the coordinates of the millimeter-sized deep brain nuclei is performed in relation to the three-dimensional space defined
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head, and an MRI is obtained with the frame in place. Calculation of the coordinates of the millimeter-sized deep brain nuclei is performed in relation to the three-dimensional space defined by the fixed frame, allowing for accurate targeting of the nucleus (Fig. 42-33). Postoperatively, the pulse generators can be interrogated and adjusted with hand-held, transcutane-ous, noninvasive devices as needed for symptom control.Essential Tremor. Essential tremor is the most common movement disorder in the western world and is characterized by action tremor (4–8 Hz rhythmic oscillations) of the hands, forearms, head, and voice. Essential tremor often starts in the third or fourth decade of life and increases in frequency and amplitude with age. β-Blockers can decrease symptoms, but patients with poor medical control and significant functional impairment significantly benefit from placement of a deep brain stimulator in the contralateral ventralis intermediate nucleus of the thalamus. In
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Surgery_Schwartz. head, and an MRI is obtained with the frame in place. Calculation of the coordinates of the millimeter-sized deep brain nuclei is performed in relation to the three-dimensional space defined by the fixed frame, allowing for accurate targeting of the nucleus (Fig. 42-33). Postoperatively, the pulse generators can be interrogated and adjusted with hand-held, transcutane-ous, noninvasive devices as needed for symptom control.Essential Tremor. Essential tremor is the most common movement disorder in the western world and is characterized by action tremor (4–8 Hz rhythmic oscillations) of the hands, forearms, head, and voice. Essential tremor often starts in the third or fourth decade of life and increases in frequency and amplitude with age. β-Blockers can decrease symptoms, but patients with poor medical control and significant functional impairment significantly benefit from placement of a deep brain stimulator in the contralateral ventralis intermediate nucleus of the thalamus. In
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with poor medical control and significant functional impairment significantly benefit from placement of a deep brain stimulator in the contralateral ventralis intermediate nucleus of the thalamus. In properly selected patients, DBS of this region of the thalamus appears to provide robust and durable symptom control.84,85Parkinson’s Disease. Parkinson’s disease is a progressive dis-order characterized by rigidity, bradykinesia, and resting tremor, due to loss of dopamine-secreting neurons in the substantia nigra. Dopaminergic agents such as levodopa/carbidopa and anticholinergic agents such as amantadine and selegiline form the basis of medical therapy. Patients with poor medical control or significant drug side effects may benefit significantly from placement of bilateral deep brain stimulators in the subthalamic nuclei. Although the globus pallidus interna has also been a widely targeted area, the subthalamic nuclei is now the most accepted target in deep brain stimulation for
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Surgery_Schwartz. with poor medical control and significant functional impairment significantly benefit from placement of a deep brain stimulator in the contralateral ventralis intermediate nucleus of the thalamus. In properly selected patients, DBS of this region of the thalamus appears to provide robust and durable symptom control.84,85Parkinson’s Disease. Parkinson’s disease is a progressive dis-order characterized by rigidity, bradykinesia, and resting tremor, due to loss of dopamine-secreting neurons in the substantia nigra. Dopaminergic agents such as levodopa/carbidopa and anticholinergic agents such as amantadine and selegiline form the basis of medical therapy. Patients with poor medical control or significant drug side effects may benefit significantly from placement of bilateral deep brain stimulators in the subthalamic nuclei. Although the globus pallidus interna has also been a widely targeted area, the subthalamic nuclei is now the most accepted target in deep brain stimulation for
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stimulators in the subthalamic nuclei. Although the globus pallidus interna has also been a widely targeted area, the subthalamic nuclei is now the most accepted target in deep brain stimulation for Parkinson’s disease.86 Deep brain stimulation provides durable symp-tom relief with good postoperative neuropsychologic function in properly selected patients.87Recently, a large randomized controlled trial compared bilat-eral DBS (n = 121) to best medical therapy in advanced Parkin-son’s disease (n = 134).88 The DBS group did significantly better in both motor function and quality of life. While adverse events were 3.8 times more likely in the DBS group, 99% of these events had resolved by 6 months. There was a 0.8% risk of death due to the procedure, and there was no difference in risk of adverse events when comparing older (≥70 years) to younger patients (<70 years). Thus, the benefits of DBS over medical therapy are clear, especially when considering quality of life measures.Another
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Surgery_Schwartz. stimulators in the subthalamic nuclei. Although the globus pallidus interna has also been a widely targeted area, the subthalamic nuclei is now the most accepted target in deep brain stimulation for Parkinson’s disease.86 Deep brain stimulation provides durable symp-tom relief with good postoperative neuropsychologic function in properly selected patients.87Recently, a large randomized controlled trial compared bilat-eral DBS (n = 121) to best medical therapy in advanced Parkin-son’s disease (n = 134).88 The DBS group did significantly better in both motor function and quality of life. While adverse events were 3.8 times more likely in the DBS group, 99% of these events had resolved by 6 months. There was a 0.8% risk of death due to the procedure, and there was no difference in risk of adverse events when comparing older (≥70 years) to younger patients (<70 years). Thus, the benefits of DBS over medical therapy are clear, especially when considering quality of life measures.Another
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adverse events when comparing older (≥70 years) to younger patients (<70 years). Thus, the benefits of DBS over medical therapy are clear, especially when considering quality of life measures.Another recent randomized controlled trial focused on defining the optimal targets for DBS in Parkinson’s disease.89 While the subthalamic nucleus (STN) and the globus pallidus interna (GPi) have been successfully targeted in the past, a direct comparison of the two was lacking. In this study, 299 subjects were randomized to receive either bilateral STN or GPi stimula-tors and were evaluated for 2 years. The primary outcome was motor function, as assessed by part III of the Unified Parkin-son’s Disease Rating Scale (UPDRS). The study found no sig-nificant difference in motor improvement between target sites. However, a significant difference was found in a secondary outcome measuring depression. On the Beck Depression Inven-tory, the pallidal stimulation group improved slightly compared with the
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Surgery_Schwartz. adverse events when comparing older (≥70 years) to younger patients (<70 years). Thus, the benefits of DBS over medical therapy are clear, especially when considering quality of life measures.Another recent randomized controlled trial focused on defining the optimal targets for DBS in Parkinson’s disease.89 While the subthalamic nucleus (STN) and the globus pallidus interna (GPi) have been successfully targeted in the past, a direct comparison of the two was lacking. In this study, 299 subjects were randomized to receive either bilateral STN or GPi stimula-tors and were evaluated for 2 years. The primary outcome was motor function, as assessed by part III of the Unified Parkin-son’s Disease Rating Scale (UPDRS). The study found no sig-nificant difference in motor improvement between target sites. However, a significant difference was found in a secondary outcome measuring depression. On the Beck Depression Inven-tory, the pallidal stimulation group improved slightly compared with the
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sites. However, a significant difference was found in a secondary outcome measuring depression. On the Beck Depression Inven-tory, the pallidal stimulation group improved slightly compared with the STN group, which actually worsened slightly. Never-theless, the actual incidence of depressive episodes requiring prolonged or new hospitalization was 2.6% and 0.7% in GPi and STN, respectively, which was not significantly different. On the other hand, the STN group was found to require less adjunctive dopaminergic pharmacotherapy than the GPi group. In terms of overall severe adverse events, there was no difference between groups. The investigators concluded that both target sites are effective and that nonmotor factors such as psychiatric symp-toms may be a consideration in DBS target selection.Dystonia. The FDA humanitarian device exemption has been made for DBS for dystonia but is limited to patients ≥7 years of age with primary dystonia, including generalized and/or seg-mental
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Surgery_Schwartz. sites. However, a significant difference was found in a secondary outcome measuring depression. On the Beck Depression Inven-tory, the pallidal stimulation group improved slightly compared with the STN group, which actually worsened slightly. Never-theless, the actual incidence of depressive episodes requiring prolonged or new hospitalization was 2.6% and 0.7% in GPi and STN, respectively, which was not significantly different. On the other hand, the STN group was found to require less adjunctive dopaminergic pharmacotherapy than the GPi group. In terms of overall severe adverse events, there was no difference between groups. The investigators concluded that both target sites are effective and that nonmotor factors such as psychiatric symp-toms may be a consideration in DBS target selection.Dystonia. The FDA humanitarian device exemption has been made for DBS for dystonia but is limited to patients ≥7 years of age with primary dystonia, including generalized and/or seg-mental
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selection.Dystonia. The FDA humanitarian device exemption has been made for DBS for dystonia but is limited to patients ≥7 years of age with primary dystonia, including generalized and/or seg-mental dystonia, hemidystonia, or cervical dystonia (torticollis). Dystonia is characterized by sustained muscle contractions that cause repetitive movements and involuntary postures. Cognitive function is typically spared, and pharmacological therapy is fre-quently inadequate. The positive impact of DBS on Parkinson’s and essential tremor has led neurologists and neurosurgeons to direct their attention to DBS for treatment of idiopathic focal and generalized dystonia.Although the pathophysiology of idiopathic dystonia is unclear, positron emission tomography studies have shown disturbed glucose metabolism in the GPi, suggesting secondary pathologic activation of the motor cortex. Indeed, the GPi is cur-rently considered the most efficacious target for dystonia, and controlled trials indicate
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Surgery_Schwartz. selection.Dystonia. The FDA humanitarian device exemption has been made for DBS for dystonia but is limited to patients ≥7 years of age with primary dystonia, including generalized and/or seg-mental dystonia, hemidystonia, or cervical dystonia (torticollis). Dystonia is characterized by sustained muscle contractions that cause repetitive movements and involuntary postures. Cognitive function is typically spared, and pharmacological therapy is fre-quently inadequate. The positive impact of DBS on Parkinson’s and essential tremor has led neurologists and neurosurgeons to direct their attention to DBS for treatment of idiopathic focal and generalized dystonia.Although the pathophysiology of idiopathic dystonia is unclear, positron emission tomography studies have shown disturbed glucose metabolism in the GPi, suggesting secondary pathologic activation of the motor cortex. Indeed, the GPi is cur-rently considered the most efficacious target for dystonia, and controlled trials indicate
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in the GPi, suggesting secondary pathologic activation of the motor cortex. Indeed, the GPi is cur-rently considered the most efficacious target for dystonia, and controlled trials indicate approximately a 50% improvement in motor function and disability.90 Since many patients undergoing 8Figure 42-33. Fast spin echo coronal magnetic resonance imaging demonstrating position of deep brain stimulator leads in the subtha-lamic nuclei bilaterally. The electrodes appear thick and wavy due to magnetic susceptibility artifact.Brunicardi_Ch42_p1827-p1878.indd 187001/03/19 7:17 PM 1871NEUROSURGERYCHAPTER 42surgery for dystonia are children and young adults, DBS is an attractive surgical option because it can be titrated, revised, and reversed according to individual needs and growth patterns.Obsessive-Compulsive Disorder. The safety and efficacy of DBS, as well as its titratability and reversibility, that have been demonstrated for the treatment of movement disorders in the 1990s and 2000s
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Surgery_Schwartz. in the GPi, suggesting secondary pathologic activation of the motor cortex. Indeed, the GPi is cur-rently considered the most efficacious target for dystonia, and controlled trials indicate approximately a 50% improvement in motor function and disability.90 Since many patients undergoing 8Figure 42-33. Fast spin echo coronal magnetic resonance imaging demonstrating position of deep brain stimulator leads in the subtha-lamic nuclei bilaterally. The electrodes appear thick and wavy due to magnetic susceptibility artifact.Brunicardi_Ch42_p1827-p1878.indd 187001/03/19 7:17 PM 1871NEUROSURGERYCHAPTER 42surgery for dystonia are children and young adults, DBS is an attractive surgical option because it can be titrated, revised, and reversed according to individual needs and growth patterns.Obsessive-Compulsive Disorder. The safety and efficacy of DBS, as well as its titratability and reversibility, that have been demonstrated for the treatment of movement disorders in the 1990s and 2000s
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Disorder. The safety and efficacy of DBS, as well as its titratability and reversibility, that have been demonstrated for the treatment of movement disorders in the 1990s and 2000s has spawned an increasing interest and awareness of the capabilities of nonlesional surgical treatments for diseases of the brain. An obvious outgrowth of DBS for movement disorders has been the treatment of medically refrac-tory psychiatric disorders. Despite the dark history of frontal leucotomy procedures that dominated the early 20th century, nonlesional DBS for psychiatric disorders are now considered potential treatment strategies.Functional neuroimaging has implicated certain brain regions in the pathogenesis of a variety of psychiatric disorders. The FDA has approved a humanitarian device exemption for DBS targeting the ventral capsule/ventral striatum for severe obsessive-compulsive disorder (OCD). Recent case reports and pilot studies have reported remission in patients suffering from refractory
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Surgery_Schwartz. Disorder. The safety and efficacy of DBS, as well as its titratability and reversibility, that have been demonstrated for the treatment of movement disorders in the 1990s and 2000s has spawned an increasing interest and awareness of the capabilities of nonlesional surgical treatments for diseases of the brain. An obvious outgrowth of DBS for movement disorders has been the treatment of medically refrac-tory psychiatric disorders. Despite the dark history of frontal leucotomy procedures that dominated the early 20th century, nonlesional DBS for psychiatric disorders are now considered potential treatment strategies.Functional neuroimaging has implicated certain brain regions in the pathogenesis of a variety of psychiatric disorders. The FDA has approved a humanitarian device exemption for DBS targeting the ventral capsule/ventral striatum for severe obsessive-compulsive disorder (OCD). Recent case reports and pilot studies have reported remission in patients suffering from refractory
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DBS targeting the ventral capsule/ventral striatum for severe obsessive-compulsive disorder (OCD). Recent case reports and pilot studies have reported remission in patients suffering from refractory OCD following DBS. A pilot study using a blinded, staggered-onset design found that four (66.7%) of six patients met a stringent criterion as “responders” (≥35% improvement), according to the Yale-Brown Obsessive Compulsive Scale after 12 months of stimulation.91 In this study, patients did not improve during the sham phase. Adverse events were generally mild and modifiable with setting changes, and stimulation inter-ruption led to rapid yet reversible development of depressive symptoms in two cases. Thus, DBS has promise as a therapy of last resort for carefully selected cases of severe OCD.Expanding Indications of Deep Brain Stimulation. There are multiple disorders, both psychiatric and neurologic, that have exhibited significant promise as potential indications for DBS in large-scale
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Surgery_Schwartz. DBS targeting the ventral capsule/ventral striatum for severe obsessive-compulsive disorder (OCD). Recent case reports and pilot studies have reported remission in patients suffering from refractory OCD following DBS. A pilot study using a blinded, staggered-onset design found that four (66.7%) of six patients met a stringent criterion as “responders” (≥35% improvement), according to the Yale-Brown Obsessive Compulsive Scale after 12 months of stimulation.91 In this study, patients did not improve during the sham phase. Adverse events were generally mild and modifiable with setting changes, and stimulation inter-ruption led to rapid yet reversible development of depressive symptoms in two cases. Thus, DBS has promise as a therapy of last resort for carefully selected cases of severe OCD.Expanding Indications of Deep Brain Stimulation. There are multiple disorders, both psychiatric and neurologic, that have exhibited significant promise as potential indications for DBS in large-scale
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Indications of Deep Brain Stimulation. There are multiple disorders, both psychiatric and neurologic, that have exhibited significant promise as potential indications for DBS in large-scale trials. Recently, there have been reports of significant improvements in refractory depression with DBS. Lozano and colleagues performed an open label study with extended follow-up on 20 patients targeting an area within the subcallosal cin-gulate gyrus (SCG) with bilateral DBS.92 At the last follow-up visit in this study (range: 3–6 years), the average response rate was 64%, according to the Hamilton Rating Scale for Depres-sion. Of note, impairment in social functioning was improved, and no significant adverse events were reported. Because two patients died by suicide during depressive relapses, it remains unclear if DBS can only improve quality of life or significantly suppress relapses and extend life-span in this extremely delicate patient population. Of note, as seen in OCD, the ventral
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Surgery_Schwartz. Indications of Deep Brain Stimulation. There are multiple disorders, both psychiatric and neurologic, that have exhibited significant promise as potential indications for DBS in large-scale trials. Recently, there have been reports of significant improvements in refractory depression with DBS. Lozano and colleagues performed an open label study with extended follow-up on 20 patients targeting an area within the subcallosal cin-gulate gyrus (SCG) with bilateral DBS.92 At the last follow-up visit in this study (range: 3–6 years), the average response rate was 64%, according to the Hamilton Rating Scale for Depres-sion. Of note, impairment in social functioning was improved, and no significant adverse events were reported. Because two patients died by suicide during depressive relapses, it remains unclear if DBS can only improve quality of life or significantly suppress relapses and extend life-span in this extremely delicate patient population. Of note, as seen in OCD, the ventral
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it remains unclear if DBS can only improve quality of life or significantly suppress relapses and extend life-span in this extremely delicate patient population. Of note, as seen in OCD, the ventral capsule/ventral striatum has also been targeted for depression, as well as the nucleus accumbens directly, which lies within the ventral striatum. Studies of DBS in this region report an approximate 40% to 60% response rate, and results from a recent, multicenter randomized controlled trial are pending.93DBS as a potential therapy for epilepsy targeting the ante-rior nucleus of the thalamus has been investigated in a multi-center, double-blind, randomized trial (SANTE).94 In this trial, the group receiving DBS showed a 29% greater reduction in seizure frequency in relation to the sham group in the last month of the blinded phase. Complex partial and the “most severe” seizures were significantly reduced in the cohort who had the stimulator on DBS-on group. After the blinded phase of the
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Surgery_Schwartz. it remains unclear if DBS can only improve quality of life or significantly suppress relapses and extend life-span in this extremely delicate patient population. Of note, as seen in OCD, the ventral capsule/ventral striatum has also been targeted for depression, as well as the nucleus accumbens directly, which lies within the ventral striatum. Studies of DBS in this region report an approximate 40% to 60% response rate, and results from a recent, multicenter randomized controlled trial are pending.93DBS as a potential therapy for epilepsy targeting the ante-rior nucleus of the thalamus has been investigated in a multi-center, double-blind, randomized trial (SANTE).94 In this trial, the group receiving DBS showed a 29% greater reduction in seizure frequency in relation to the sham group in the last month of the blinded phase. Complex partial and the “most severe” seizures were significantly reduced in the cohort who had the stimulator on DBS-on group. After the blinded phase of the
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in the last month of the blinded phase. Complex partial and the “most severe” seizures were significantly reduced in the cohort who had the stimulator on DBS-on group. After the blinded phase of the trial was complete, 54% of patients had a seizure reduction of at least 50%. Fourteen patients were seizure-free for at least 6 months; eight were seizure-free for at least one year, four for at least two years, and one patient for more than four years. Because of the modest benefit during the blinded phase of this trial, FDA-approval has yet to be granted to DBS for epilepsy targeting the thalamus in the United States, though approval has been given in Europe and Canada.The region-specific, neuromodulatory capabilities of DBS have inspired the open label use of this technique in many other neurologic and psychiatric disorders, including but not limited to Tourette syndrome, Huntington’s disease, and Alzheimer dis-ease. Preclinical studies of both substance abuse and obesity have also
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Surgery_Schwartz. in the last month of the blinded phase. Complex partial and the “most severe” seizures were significantly reduced in the cohort who had the stimulator on DBS-on group. After the blinded phase of the trial was complete, 54% of patients had a seizure reduction of at least 50%. Fourteen patients were seizure-free for at least 6 months; eight were seizure-free for at least one year, four for at least two years, and one patient for more than four years. Because of the modest benefit during the blinded phase of this trial, FDA-approval has yet to be granted to DBS for epilepsy targeting the thalamus in the United States, though approval has been given in Europe and Canada.The region-specific, neuromodulatory capabilities of DBS have inspired the open label use of this technique in many other neurologic and psychiatric disorders, including but not limited to Tourette syndrome, Huntington’s disease, and Alzheimer dis-ease. Preclinical studies of both substance abuse and obesity have also
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neurologic and psychiatric disorders, including but not limited to Tourette syndrome, Huntington’s disease, and Alzheimer dis-ease. Preclinical studies of both substance abuse and obesity have also shown promise.95,96 The opportunity to model reward-seeking behaviors associated with these disorders in animals provides the ability to not only test safety but also study mecha-nisms and inform the design of future clinical trials.Trigeminal NeuralgiaTrigeminal neuralgia, also known as tic douloureux, is charac-terized by repetitive, unilateral, sharp, and lancinating pains in the distribution of, typically, the second, but sometimes third, branch of cranial nerve V, the trigeminal nerve. The patient may describe a “trigger point,” an area on the face that elicits the pain when touched. A current leading etiologic hypothesis for trigeminal neuralgia is irritation and pulsatile compression of the root entry zone of the nerve by an artery in the posterior fossa, usually a loop of the
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Surgery_Schwartz. neurologic and psychiatric disorders, including but not limited to Tourette syndrome, Huntington’s disease, and Alzheimer dis-ease. Preclinical studies of both substance abuse and obesity have also shown promise.95,96 The opportunity to model reward-seeking behaviors associated with these disorders in animals provides the ability to not only test safety but also study mecha-nisms and inform the design of future clinical trials.Trigeminal NeuralgiaTrigeminal neuralgia, also known as tic douloureux, is charac-terized by repetitive, unilateral, sharp, and lancinating pains in the distribution of, typically, the second, but sometimes third, branch of cranial nerve V, the trigeminal nerve. The patient may describe a “trigger point,” an area on the face that elicits the pain when touched. A current leading etiologic hypothesis for trigeminal neuralgia is irritation and pulsatile compression of the root entry zone of the nerve by an artery in the posterior fossa, usually a loop of the
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A current leading etiologic hypothesis for trigeminal neuralgia is irritation and pulsatile compression of the root entry zone of the nerve by an artery in the posterior fossa, usually a loop of the superior cerebellar artery. The pain is excruciating and can be debilitating. Medical therapy, including carbamazepine and amitriptyline, may reduce the frequency of events. Options for medically refractory cases include percuta-neous injection of glycerol into the path of the nerve, periph-eral transection of the nerve branches, SRS, and microvascular decompression (MVD).MVD involves performing a small posterior fossa crani-otomy on the side of the symptoms, retraction of the cerebellar hemisphere, and exploration of cranial nerve V. If an artery is found near the nerve, the vessel is freed of any adhesions and nonabsorbable material is placed between the nerve root and the artery. MVD remains the first definitive management option because SRS is associated with a substantial incidence of
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Surgery_Schwartz. A current leading etiologic hypothesis for trigeminal neuralgia is irritation and pulsatile compression of the root entry zone of the nerve by an artery in the posterior fossa, usually a loop of the superior cerebellar artery. The pain is excruciating and can be debilitating. Medical therapy, including carbamazepine and amitriptyline, may reduce the frequency of events. Options for medically refractory cases include percuta-neous injection of glycerol into the path of the nerve, periph-eral transection of the nerve branches, SRS, and microvascular decompression (MVD).MVD involves performing a small posterior fossa crani-otomy on the side of the symptoms, retraction of the cerebellar hemisphere, and exploration of cranial nerve V. If an artery is found near the nerve, the vessel is freed of any adhesions and nonabsorbable material is placed between the nerve root and the artery. MVD remains the first definitive management option because SRS is associated with a substantial incidence of
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any adhesions and nonabsorbable material is placed between the nerve root and the artery. MVD remains the first definitive management option because SRS is associated with a substantial incidence of facial numbness.97,98STEREOTACTIC RADIOSURGERYThe term stereotactic radiosurgery (SRS) refers to techniques that allow delivery of high-dose radiation that conforms to the shape of the target and has rapid isodose fall-off, minimiz-ing damage to adjacent neural structures. The two most common devices used for conformal SRS for intracranial lesions are the LINAC (linear accelerator) and the gamma knife. LINAC delivers a focused beam of x-ray radiation from a port that arcs part way around the patient’s head. Linear accelerators are commonly used to provide fractionated radiation for lesions outside the CNS. They are found in most radiation oncology departments. After upgrades to the software and collimators, SRS can be performed with these existing units. The gamma knife delivers 201
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Surgery_Schwartz. any adhesions and nonabsorbable material is placed between the nerve root and the artery. MVD remains the first definitive management option because SRS is associated with a substantial incidence of facial numbness.97,98STEREOTACTIC RADIOSURGERYThe term stereotactic radiosurgery (SRS) refers to techniques that allow delivery of high-dose radiation that conforms to the shape of the target and has rapid isodose fall-off, minimiz-ing damage to adjacent neural structures. The two most common devices used for conformal SRS for intracranial lesions are the LINAC (linear accelerator) and the gamma knife. LINAC delivers a focused beam of x-ray radiation from a port that arcs part way around the patient’s head. Linear accelerators are commonly used to provide fractionated radiation for lesions outside the CNS. They are found in most radiation oncology departments. After upgrades to the software and collimators, SRS can be performed with these existing units. The gamma knife delivers 201
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outside the CNS. They are found in most radiation oncology departments. After upgrades to the software and collimators, SRS can be performed with these existing units. The gamma knife delivers 201 focused beams of gamma radiation from cobalt sources through a specially designed colander-like helmet. Gamma knife units are used only for intracranial disease and cost up to $5 million; thus, they are most appropriate in high patient–volume centers. There is ongoing debate in the literature 9Brunicardi_Ch42_p1827-p1878.indd 187101/03/19 7:17 PM 1872SPECIFIC CONSIDERATIONSPART IIregarding the two technologies.99-101 Both continue to evolve, allowing more precise and complex isodose conformation to complex lesions. Most lesions can be treated equally well with either technology. Lesions abutting the medulla or the spinal cord should not be treated with SRS because these structures do not tolerate the radiation dose delivered to structures within mil-limeters of the target. Also,
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Surgery_Schwartz. outside the CNS. They are found in most radiation oncology departments. After upgrades to the software and collimators, SRS can be performed with these existing units. The gamma knife delivers 201 focused beams of gamma radiation from cobalt sources through a specially designed colander-like helmet. Gamma knife units are used only for intracranial disease and cost up to $5 million; thus, they are most appropriate in high patient–volume centers. There is ongoing debate in the literature 9Brunicardi_Ch42_p1827-p1878.indd 187101/03/19 7:17 PM 1872SPECIFIC CONSIDERATIONSPART IIregarding the two technologies.99-101 Both continue to evolve, allowing more precise and complex isodose conformation to complex lesions. Most lesions can be treated equally well with either technology. Lesions abutting the medulla or the spinal cord should not be treated with SRS because these structures do not tolerate the radiation dose delivered to structures within mil-limeters of the target. Also,
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abutting the medulla or the spinal cord should not be treated with SRS because these structures do not tolerate the radiation dose delivered to structures within mil-limeters of the target. Also, medullary or spinal cord compres-sion can result from swelling of the lesion after the radiosurgery dose, resulting in devastating neurologic deficit.Proton beam is an evolving SRS technology that may play a specialized role in treatment of lesions where posttarget exit-ing radiation limits photon-based therapies.102 For example, the physical properties of photons cause destruction upon entry and exit from tissue, which can be particularly harmful to skull-base or clival lesions such as chordoma, in which the exiting pathway travels through the brain stem. Proton beam therapy uses accel-erated protons, which dissipate energy upon impact and do not cause additional exiting damage. Currently, there are very few centers using this technology.CyberKnife is another radiosurgery system that has
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Surgery_Schwartz. abutting the medulla or the spinal cord should not be treated with SRS because these structures do not tolerate the radiation dose delivered to structures within mil-limeters of the target. Also, medullary or spinal cord compres-sion can result from swelling of the lesion after the radiosurgery dose, resulting in devastating neurologic deficit.Proton beam is an evolving SRS technology that may play a specialized role in treatment of lesions where posttarget exit-ing radiation limits photon-based therapies.102 For example, the physical properties of photons cause destruction upon entry and exit from tissue, which can be particularly harmful to skull-base or clival lesions such as chordoma, in which the exiting pathway travels through the brain stem. Proton beam therapy uses accel-erated protons, which dissipate energy upon impact and do not cause additional exiting damage. Currently, there are very few centers using this technology.CyberKnife is another radiosurgery system that has
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Surgery_Schwartz_12390
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protons, which dissipate energy upon impact and do not cause additional exiting damage. Currently, there are very few centers using this technology.CyberKnife is another radiosurgery system that has neu-rosurgical application. It is a frameless, robotic, LINAC-based system that allows for targeting of spinal neoplasms with higher resolution than conventional external beam radiotherapy.103 Using imaging tracking in real time, the CyberKnife is able to adjust to breathing artifact and patient movement. The applica-tion of this technology is rapidly growing.Arteriovenous MalformationsSRS has been found to be an effective stand-alone therapy for AVMs up to 3 cm in diameter. SRS is best for lesions that are dif-ficult to access surgically due to high likelihood of postoperative neurologic deficit. However, SRS is not effective for lesions >3 cm. Effective obliteration and elimination of the risk of hemorrhage takes 2 to 3 years. Overall, there is an approximately 2% annual incidence of AVM
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Surgery_Schwartz. protons, which dissipate energy upon impact and do not cause additional exiting damage. Currently, there are very few centers using this technology.CyberKnife is another radiosurgery system that has neu-rosurgical application. It is a frameless, robotic, LINAC-based system that allows for targeting of spinal neoplasms with higher resolution than conventional external beam radiotherapy.103 Using imaging tracking in real time, the CyberKnife is able to adjust to breathing artifact and patient movement. The applica-tion of this technology is rapidly growing.Arteriovenous MalformationsSRS has been found to be an effective stand-alone therapy for AVMs up to 3 cm in diameter. SRS is best for lesions that are dif-ficult to access surgically due to high likelihood of postoperative neurologic deficit. However, SRS is not effective for lesions >3 cm. Effective obliteration and elimination of the risk of hemorrhage takes 2 to 3 years. Overall, there is an approximately 2% annual incidence of AVM
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Surgery_Schwartz_12391
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Surgery_Schwartz
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However, SRS is not effective for lesions >3 cm. Effective obliteration and elimination of the risk of hemorrhage takes 2 to 3 years. Overall, there is an approximately 2% annual incidence of AVM hemorrhage,104 although one study found a 50% decrease in hemorrhage rate during the latency period before angiographic obliteration.105 Nonetheless, surgical excision remains the preferred therapeutic modality, while SRS is reserved for cases deemed very high risk for surgery due to location or patient factors.106 Some patients with large AVMs who undergo surgery will have unresectable residual lesions. In these patients, SRS may be used as an effective adjunctive therapy.Vestibular SchwannomasSRS has been introduced as a therapeutic alternative to micro-surgical resection for vestibular schwannomas up to 2.5 cm in maximum diameter. SRS provides high rates of tumor growth arrest and possible reduction in size with low rates of facial nerve palsy. Patients with functional ipsilateral
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Surgery_Schwartz. However, SRS is not effective for lesions >3 cm. Effective obliteration and elimination of the risk of hemorrhage takes 2 to 3 years. Overall, there is an approximately 2% annual incidence of AVM hemorrhage,104 although one study found a 50% decrease in hemorrhage rate during the latency period before angiographic obliteration.105 Nonetheless, surgical excision remains the preferred therapeutic modality, while SRS is reserved for cases deemed very high risk for surgery due to location or patient factors.106 Some patients with large AVMs who undergo surgery will have unresectable residual lesions. In these patients, SRS may be used as an effective adjunctive therapy.Vestibular SchwannomasSRS has been introduced as a therapeutic alternative to micro-surgical resection for vestibular schwannomas up to 2.5 cm in maximum diameter. SRS provides high rates of tumor growth arrest and possible reduction in size with low rates of facial nerve palsy. Patients with functional ipsilateral
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Surgery_Schwartz_12392
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schwannomas up to 2.5 cm in maximum diameter. SRS provides high rates of tumor growth arrest and possible reduction in size with low rates of facial nerve palsy. Patients with functional ipsilateral preprocedure hearing may be more likely to retain functional hearing postpro-cedure than with microsurgery. The limitations of SRS include inability to treat tumors >2.5 cm, the possibility of radiation-induced malignant transformation of these benign tumors, and lack of long-term follow-up. SRS centers are accumulating experience with these tumors and accumulating data on long-term results.107,108 The indications for microsurgery and SRS will continue to evolve. Either approach should be undertaken at a high-volume center, as studies show the patient outcomes improve with increased surgeon experience.109Intracranial MetastasesPatients with solitary or multiple intracranial metastases may be treated primarily with SRS.110 Patients have improved survival after SRS compared to no treatment
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Surgery_Schwartz. schwannomas up to 2.5 cm in maximum diameter. SRS provides high rates of tumor growth arrest and possible reduction in size with low rates of facial nerve palsy. Patients with functional ipsilateral preprocedure hearing may be more likely to retain functional hearing postpro-cedure than with microsurgery. The limitations of SRS include inability to treat tumors >2.5 cm, the possibility of radiation-induced malignant transformation of these benign tumors, and lack of long-term follow-up. SRS centers are accumulating experience with these tumors and accumulating data on long-term results.107,108 The indications for microsurgery and SRS will continue to evolve. Either approach should be undertaken at a high-volume center, as studies show the patient outcomes improve with increased surgeon experience.109Intracranial MetastasesPatients with solitary or multiple intracranial metastases may be treated primarily with SRS.110 Patients have improved survival after SRS compared to no treatment
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Surgery_Schwartz_12393
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Surgery_Schwartz
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MetastasesPatients with solitary or multiple intracranial metastases may be treated primarily with SRS.110 Patients have improved survival after SRS compared to no treatment or WBRT, and similar sur-vival to patients undergoing total surgical resection. Patients with lesions >3 cm in diameter or evidence of ICH should undergo surgical decompression rather than SRS. Some studies show improved survival with up to seven intracranial masses. Patients with multiple intracranial masses have almost zero long-term survival, and most will die of their intracranial dis-ease. Patients with intracranial metastases live 3 to 6 months on average with medical care and WBRT. This can be extended to 9 to 16 months with SRS or surgery, depending on tumor type, age, and patient condition.111CONGENITAL AND DEVELOPMENTAL ANOMALIESDysraphismDysraphism describes defects of fusion of the neural tube involving the neural tube itself, or overlying bone or skin. Dys-raphism may occur in the spine or head.
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Surgery_Schwartz. MetastasesPatients with solitary or multiple intracranial metastases may be treated primarily with SRS.110 Patients have improved survival after SRS compared to no treatment or WBRT, and similar sur-vival to patients undergoing total surgical resection. Patients with lesions >3 cm in diameter or evidence of ICH should undergo surgical decompression rather than SRS. Some studies show improved survival with up to seven intracranial masses. Patients with multiple intracranial masses have almost zero long-term survival, and most will die of their intracranial dis-ease. Patients with intracranial metastases live 3 to 6 months on average with medical care and WBRT. This can be extended to 9 to 16 months with SRS or surgery, depending on tumor type, age, and patient condition.111CONGENITAL AND DEVELOPMENTAL ANOMALIESDysraphismDysraphism describes defects of fusion of the neural tube involving the neural tube itself, or overlying bone or skin. Dys-raphism may occur in the spine or head.
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Surgery_Schwartz_12394
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Surgery_Schwartz
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AND DEVELOPMENTAL ANOMALIESDysraphismDysraphism describes defects of fusion of the neural tube involving the neural tube itself, or overlying bone or skin. Dys-raphism may occur in the spine or head. Neural tube defects are among the most common congenital abnormalities. Prenatal vitamins, especially folic acid, reduce the incidence of neural tube defects.Spina Bifida OccultaSpina bifida occulta is congenital absence of posterior vertebral elements. The spinous process is always missing, the laminae may be missing to various degrees, but the underlying neural tissues are not involved. Spina bifida occulta is found in 25% of the general population, and it is asymptomatic unless associated with other developmental abnormalities.Spina Bifida With MyelomeningoceleSpina bifida with myelomeningocele describes the congenital absence of posterior vertebral elements with protrusion of the meninges through the defect, with underlying neural structural abnormalities. Common findings include
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Surgery_Schwartz. AND DEVELOPMENTAL ANOMALIESDysraphismDysraphism describes defects of fusion of the neural tube involving the neural tube itself, or overlying bone or skin. Dys-raphism may occur in the spine or head. Neural tube defects are among the most common congenital abnormalities. Prenatal vitamins, especially folic acid, reduce the incidence of neural tube defects.Spina Bifida OccultaSpina bifida occulta is congenital absence of posterior vertebral elements. The spinous process is always missing, the laminae may be missing to various degrees, but the underlying neural tissues are not involved. Spina bifida occulta is found in 25% of the general population, and it is asymptomatic unless associated with other developmental abnormalities.Spina Bifida With MyelomeningoceleSpina bifida with myelomeningocele describes the congenital absence of posterior vertebral elements with protrusion of the meninges through the defect, with underlying neural structural abnormalities. Common findings include
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Surgery_Schwartz_12395
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Surgery_Schwartz
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describes the congenital absence of posterior vertebral elements with protrusion of the meninges through the defect, with underlying neural structural abnormalities. Common findings include weakness and atrophy of the lower extremities, gait disturbance, urinary incontinence, constipation, and deformities of the foot. Myelomeningoceles arising from the high lumbar cord usually cause total paraly-sis and incontinence, while those arising from the sacral cord may have only clawing of the foot and partial urinary function loss. Myelomeningocele patients often have hydrocephalus and a Chiari II malformation, an abnormal downward herniation of the cerebellum and brain stem through the foramen magnum. Patients with abnormal protrusion of meninges through the bony defect without abnormalities of the underlying neural tissue have a meningocele. Most of these patients are neurologically normal.EncephaloceleHerniation of brain encased in meninges through the skull that forms an intracranial
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Surgery_Schwartz. describes the congenital absence of posterior vertebral elements with protrusion of the meninges through the defect, with underlying neural structural abnormalities. Common findings include weakness and atrophy of the lower extremities, gait disturbance, urinary incontinence, constipation, and deformities of the foot. Myelomeningoceles arising from the high lumbar cord usually cause total paraly-sis and incontinence, while those arising from the sacral cord may have only clawing of the foot and partial urinary function loss. Myelomeningocele patients often have hydrocephalus and a Chiari II malformation, an abnormal downward herniation of the cerebellum and brain stem through the foramen magnum. Patients with abnormal protrusion of meninges through the bony defect without abnormalities of the underlying neural tissue have a meningocele. Most of these patients are neurologically normal.EncephaloceleHerniation of brain encased in meninges through the skull that forms an intracranial
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Surgery_Schwartz_12396
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of the underlying neural tissue have a meningocele. Most of these patients are neurologically normal.EncephaloceleHerniation of brain encased in meninges through the skull that forms an intracranial mass is referred to as encephalocele. Herniation of meninges without brain tissue is referred to as a meningocele. Most occur over the convexity of the skull. More rarely, the tissue protrudes through the skull base into the sinuses. Treatment involves excision of the herniated tissue and closure of the defect. Most patients with encephaloceles and meningoceles have impaired cognitive development. Patients with greater amounts of herniated neural tissue tend to have more severe cognitive deficits.CraniosynostosisCraniosynostosis is the abnormal early fusion of a cranial suture line with resultant restriction of skull growth in the affected area Brunicardi_Ch42_p1827-p1878.indd 187201/03/19 7:17 PM 1873NEUROSURGERYCHAPTER 42Figure 42-34. A. Axial head computed tomography scan revealing
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Surgery_Schwartz. of the underlying neural tissue have a meningocele. Most of these patients are neurologically normal.EncephaloceleHerniation of brain encased in meninges through the skull that forms an intracranial mass is referred to as encephalocele. Herniation of meninges without brain tissue is referred to as a meningocele. Most occur over the convexity of the skull. More rarely, the tissue protrudes through the skull base into the sinuses. Treatment involves excision of the herniated tissue and closure of the defect. Most patients with encephaloceles and meningoceles have impaired cognitive development. Patients with greater amounts of herniated neural tissue tend to have more severe cognitive deficits.CraniosynostosisCraniosynostosis is the abnormal early fusion of a cranial suture line with resultant restriction of skull growth in the affected area Brunicardi_Ch42_p1827-p1878.indd 187201/03/19 7:17 PM 1873NEUROSURGERYCHAPTER 42Figure 42-34. A. Axial head computed tomography scan revealing
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Surgery_Schwartz_12397
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Surgery_Schwartz
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restriction of skull growth in the affected area Brunicardi_Ch42_p1827-p1878.indd 187201/03/19 7:17 PM 1873NEUROSURGERYCHAPTER 42Figure 42-34. A. Axial head computed tomography scan revealing dilated ventricular system. Note dilated atria of the lateral ventricles (arrowheads) and rounded third ventricle (arrow). The large size of the ventricles and lack of transependymal flow indicate a chronic process (contrast to Fig. 42-2). The patient had normal-pressure hydrocephalus and had improved ambulation after placement of a ventriculoperitoneal shunt. B. Higher cut from same scan showing ventricular catheter in place in the frontal horn of the right lateral ventricle.ABand compensatory bulging at the other sutures. Skull growth occurs at the cranial sutures for the first 2 years of life, at the end of which the skull has achieved >90% of its eventual adult size. Fusion of the sagittal suture, or sagittal synostosis, results in a boat-shaped head, known as scaphocephaly. Unilateral
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Surgery_Schwartz. restriction of skull growth in the affected area Brunicardi_Ch42_p1827-p1878.indd 187201/03/19 7:17 PM 1873NEUROSURGERYCHAPTER 42Figure 42-34. A. Axial head computed tomography scan revealing dilated ventricular system. Note dilated atria of the lateral ventricles (arrowheads) and rounded third ventricle (arrow). The large size of the ventricles and lack of transependymal flow indicate a chronic process (contrast to Fig. 42-2). The patient had normal-pressure hydrocephalus and had improved ambulation after placement of a ventriculoperitoneal shunt. B. Higher cut from same scan showing ventricular catheter in place in the frontal horn of the right lateral ventricle.ABand compensatory bulging at the other sutures. Skull growth occurs at the cranial sutures for the first 2 years of life, at the end of which the skull has achieved >90% of its eventual adult size. Fusion of the sagittal suture, or sagittal synostosis, results in a boat-shaped head, known as scaphocephaly. Unilateral
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Surgery_Schwartz_12398
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Surgery_Schwartz
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at the end of which the skull has achieved >90% of its eventual adult size. Fusion of the sagittal suture, or sagittal synostosis, results in a boat-shaped head, known as scaphocephaly. Unilateral coronal synostosis results in ipsilateral forehead flattening and outward deviation of the orbit, known as plagiocephaly. The contralat-eral normal forehead appears to bulge by comparison. Bilat-eral coronal synostosis results in a broad, flattened forehead, known as brachycephaly, and is often associated with maxil-lary hypoplasia and proptosis. Unilateral or bilateral lambdoid synostosis results in flattening of the occiput. Occipital flat-tening can result from abnormal suture fusion (synostosis), or from physical remolding of the skull caused by always placing the baby in the supine position for sleep (known as positional plagiocephaly). Placing the baby in the prone position or tilted onto the contralateral side may restore near-normal skull shape in most cases of lambdoid synostosis,
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Surgery_Schwartz. at the end of which the skull has achieved >90% of its eventual adult size. Fusion of the sagittal suture, or sagittal synostosis, results in a boat-shaped head, known as scaphocephaly. Unilateral coronal synostosis results in ipsilateral forehead flattening and outward deviation of the orbit, known as plagiocephaly. The contralat-eral normal forehead appears to bulge by comparison. Bilat-eral coronal synostosis results in a broad, flattened forehead, known as brachycephaly, and is often associated with maxil-lary hypoplasia and proptosis. Unilateral or bilateral lambdoid synostosis results in flattening of the occiput. Occipital flat-tening can result from abnormal suture fusion (synostosis), or from physical remolding of the skull caused by always placing the baby in the supine position for sleep (known as positional plagiocephaly). Placing the baby in the prone position or tilted onto the contralateral side may restore near-normal skull shape in most cases of lambdoid synostosis,
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Surgery_Schwartz_12399
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Surgery_Schwartz
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for sleep (known as positional plagiocephaly). Placing the baby in the prone position or tilted onto the contralateral side may restore near-normal skull shape in most cases of lambdoid synostosis, avoiding surgery. Treat-ment for synostoses in general is surgical, involving resection of the fused suture, or more complex reconstructive techniques for severe or refractory cases.HydrocephalusExcess CSF in the brain that results in enlarged ventricles is known as hydrocephalus. CSF flows from the ventricles to the subarachnoid space and is then absorbed into the venous blood through the arachnoid granulations. Hydrocephalus may be classified as communicating or obstructive (outlined in the next two sections), and congenital or acquired. Congenital lesions associated with or causing hydrocephalus include stenosis of the cerebral aqueduct, Chiari malformation, myelomeningo-cele, and intrauterine infection. Acquired hydrocephalus may result from occlusion of arachnoid granulations by
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Surgery_Schwartz. for sleep (known as positional plagiocephaly). Placing the baby in the prone position or tilted onto the contralateral side may restore near-normal skull shape in most cases of lambdoid synostosis, avoiding surgery. Treat-ment for synostoses in general is surgical, involving resection of the fused suture, or more complex reconstructive techniques for severe or refractory cases.HydrocephalusExcess CSF in the brain that results in enlarged ventricles is known as hydrocephalus. CSF flows from the ventricles to the subarachnoid space and is then absorbed into the venous blood through the arachnoid granulations. Hydrocephalus may be classified as communicating or obstructive (outlined in the next two sections), and congenital or acquired. Congenital lesions associated with or causing hydrocephalus include stenosis of the cerebral aqueduct, Chiari malformation, myelomeningo-cele, and intrauterine infection. Acquired hydrocephalus may result from occlusion of arachnoid granulations by
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Surgery_Schwartz_12400
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Surgery_Schwartz
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include stenosis of the cerebral aqueduct, Chiari malformation, myelomeningo-cele, and intrauterine infection. Acquired hydrocephalus may result from occlusion of arachnoid granulations by meningitis, germinal matrix hemorrhage, or SAH. CSF pathways may be occluded by adjacent tumors (Fig. 42-34).Communicating Hydrocephalus. Obstruction at the level of the arachnoid granulations constitutes communicating hydro-cephalus. This usually causes dilation of the lateral, third, and fourth ventricles equally. The most common causes in adults are meningitis and SAH. Hydrocephalus may be transient after SAH, with reestablishment of normal CSF absorption after the protein content of the CSF returns to normal and the granula-tions reopen.Obstructive Hydrocephalus. Obstruction of CSF pathways is known as obstructive hydrocephalus. Ventricles proximal to the obstruction dilate, while those distal to the obstruction remain normal in size. Typical patterns include dilation of the lateral ventricles
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Surgery_Schwartz. include stenosis of the cerebral aqueduct, Chiari malformation, myelomeningo-cele, and intrauterine infection. Acquired hydrocephalus may result from occlusion of arachnoid granulations by meningitis, germinal matrix hemorrhage, or SAH. CSF pathways may be occluded by adjacent tumors (Fig. 42-34).Communicating Hydrocephalus. Obstruction at the level of the arachnoid granulations constitutes communicating hydro-cephalus. This usually causes dilation of the lateral, third, and fourth ventricles equally. The most common causes in adults are meningitis and SAH. Hydrocephalus may be transient after SAH, with reestablishment of normal CSF absorption after the protein content of the CSF returns to normal and the granula-tions reopen.Obstructive Hydrocephalus. Obstruction of CSF pathways is known as obstructive hydrocephalus. Ventricles proximal to the obstruction dilate, while those distal to the obstruction remain normal in size. Typical patterns include dilation of the lateral ventricles
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Surgery_Schwartz_12401
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Surgery_Schwartz
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as obstructive hydrocephalus. Ventricles proximal to the obstruction dilate, while those distal to the obstruction remain normal in size. Typical patterns include dilation of the lateral ventricles due to a colloid cyst occluding the foramen of Monro, dilation of the lateral and third ventricles due to a tectal (midbrain) glioma or pineal region tumor occluding the cerebral aqueduct, or dilation of the lateral and third ventricles with obliteration of the fourth ventricle by an intraventricular tumor of the fourth ventricle. Obstructive hydrocephalus may present precipitously and require urgent shunting to prevent herniation.Chiari I MalformationChiari I malformation is the caudal displacement of the cer-ebellar tonsils below the foramen magnum. It may be seen as an incidental finding on MRI scans in asymptomatic patients. Symptomatic patients usually present with headache, neck pain, or symptoms of myelopathy, including numbness or weakness in the extremities. A syrinx may be
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Surgery_Schwartz. as obstructive hydrocephalus. Ventricles proximal to the obstruction dilate, while those distal to the obstruction remain normal in size. Typical patterns include dilation of the lateral ventricles due to a colloid cyst occluding the foramen of Monro, dilation of the lateral and third ventricles due to a tectal (midbrain) glioma or pineal region tumor occluding the cerebral aqueduct, or dilation of the lateral and third ventricles with obliteration of the fourth ventricle by an intraventricular tumor of the fourth ventricle. Obstructive hydrocephalus may present precipitously and require urgent shunting to prevent herniation.Chiari I MalformationChiari I malformation is the caudal displacement of the cer-ebellar tonsils below the foramen magnum. It may be seen as an incidental finding on MRI scans in asymptomatic patients. Symptomatic patients usually present with headache, neck pain, or symptoms of myelopathy, including numbness or weakness in the extremities. A syrinx may be
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