You are in: eMedicine Specialties > Neurosurgery > Neoplasm Spinal Cord Tumors: Management of Intradural Intramedullary NeoplasmsArticle Last Updated: Jul 1, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 13
  Author: James S Harrop, MD, Associate Professor, Departments of Neurological and Orthopedic Surgery, Jefferson Medical College James S Harrop is a member of the following medical societies: American Association of Neurological Surgeons, American College of Surgeons, American Spinal Injury Association, Cervical Spine Research Society, Congress of Neurological Surgeons, and North American Spine Society Coauthor(s): Ashwini D Sharan, MD, Assistant Professor of Neurosurgery, Assistant Professor of Neurology, Thomas Jefferson University School of Medicine Editors: Scott C Dulebohn, MD, Assistant Professor, Department of Surgery, Division of Neurosurgery, University of Minnesota College of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Allen R Wyler, MD, Former Medical Director, Northstar Neuroscience, Inc; Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy; Allen R Wyler, MD, Former Medical Director, Northstar Neuroscience, Inc Author and Editor Disclosure Synonyms and related keywords: spinal cord tumors, spinal tumors, spinal cord neoplasms, spinal neoplasms, intramedullary spinal cord tumor, intradural neoplasms, intradural tumors, intramedullary neoplasms, spine tumors, glial cell neoplasms, glial cell tumors, astrocytomas, ependymomas, hemangioblastomas, paragangliomas, oligodendrogliomas, gangliogliomas, schwannomas, meningiomas, neurofibromas, intradural intramedullary neoplasms INTRODUCTIONSection 2 of 13
  Intradural or primary spinal cord tumors (neoplasms) are uncommon lesions and fortunately affect only a minority of the population. However, when lesions grow, they result in compression of the spinal cord, which can cause limb dysfunction, motor and sensation loss, and, possibly, lead to death. Spinal tumors are classified based on their anatomic location as related to the dura mater (lining around the spinal cord) and spinal cord (medullary) as epidural, intradural extramedullary, or intradural intramedullary. Primary spinal tumors are typically intradural in location, where extradural spinal tumors are typically due to metastatic disease. This article focuses on the evaluation and management of intradural intramedullary spinal cord tumors. The typical histopathological types that account for 95% of these intramedullary neoplasms include astrocytomas, ependymomas, and hemangioblastomas. Spinal cord astrocytomas and ependymomas can be further classified as glial cell neoplasms. History of the ProcedureIn 1887, Sir Victor Horsley performed the first successful resection of an intradural neoplasm diagnosed by William Gower. This lesion was an intradural extramedullary tumor that compressed the spinal cord. However, the patient did not survive the intervention. Due to limited operative techniques, the first successful removal of an intradural intramedullary tumor, performed by Eiselsberg-Renzi, did not occur until 1907. In 1925, Charles Elsberg published the first large series of patients who underwent resections of primary spinal cord neoplasms. Unfortunately, again because of the limited operative techniques of this period, these patients endured significant surgical morbidity and mortality. However, subsequent advances in imaging, sterile operative techniques, microsurgical dissection, operating microscopy, and neurophysiologic monitoring have facilitated removal of these lesions with substantially improved clinical results. ProblemSpinal cord parenchyma consists of both gray (neurons and supporting glial cells) and white matter (axonal) and tracts that transmit impulses between the brain and body. These tracts, or circuits, control posture, movement, sensation, and autonomic system function, including bowel, bladder, and sexual function. Neurologic dysfunction develops as the spinal cord tumors enlarge and compress adjacent healthy neural tissue, disrupting these pathways. Upon further compression, patients can lose complete motor function and sensation below the lesion. In addition to weakness and sensory loss, patients may experience pain, particularly at night. This pain is believed to be related to disturbances in venous outflow by the tumor, causing engorgement and swelling of the spinal cord. FrequencyIntramedullary spinal cord tumors account for approximately 2% of adult and 10% of pediatric central nervous system neoplasms. In adults, 85-90% of intramedullary tumors are the glial subtypes, astrocytoma or ependymoma. Ependymomas account for approximately 60-70% of all spinal cord tumors found in adults, while, in children, 55-65% of intramedullary spinal cord tumors are astrocytomas. Hemangioblastomas account for 5% of tumors, whereas paragangliomas, oligodendrogliomas, and gangliogliomas account for the remaining lesions. EtiologyThe pathogenesis of spinal neoplasms is unknown, but most arise from normal cell types in the region of the spinal cord in which they develop. A genetic predisposition is likely, given the higher incidence in certain familial or syndromic groups (neurofibromatosis). Astrocytomas and ependymomas are more common in patients with neurofibromatosis type 2, which is associated with an abnormality on chromosome 22. In addition, spinal hemangioblastomas can develop in 30% of patients with von Hippel-Lindau syndrome, which is associated with an abnormality on chromosome 3. PathophysiologyThe spinal cord consists of numerous nerve bundles that descend from and ascend to the brain. Electrical impulses are carried and transmitted to facilitate movement and sensation. With intramedullary spinal cord tumors, compression and stretching of these fiber tracts results in loss of the motor and sensory function. As the tumors grow, the patient's neurologic function further deteriorates. ClinicalPatients with intramedullary glial spinal cord tumors (ie, ependymomas, astrocytomas) typically present with back pain referred from the level of the lesion, sensory changes, or worsening function. The symptoms can be of a long duration, since these lesions tend to grow slowly and typically have a benign histopathology. Patients with low-grade astrocytomas tend to experience symptoms over a mean duration of 41 months. This is in contrast to patients with malignant astrocytomas, whose symptoms persist for a mean duration of only 4-7 months before diagnosis. Tumor-specific characteristics
Physical examination findings
INDICATIONSSection 3 of 13
Intramedullary spinal cord neoplasms or tumors are typically histopathologically "benign" or slow growing. However, patients can have more aggressive neoplasms as well as morbidity due to the location of the lesion. Consequently, compared with similar intracranial neoplasms, patients may have a prolonged survival after diagnosis. Optimal treatment options depend on the patient's clinical symptoms and neurologic finding. When and whether to treat these lesions as well as perform radiosurgery or surgical excision of lesions remains controversial. However, cures have been reported only after complete surgical resection. Therefore, patients with neurologic symptoms and confirmatory findings from imaging studies may benefit most from surgical excision, with the surgical goal of total gross resection of the lesion. RELEVANT ANATOMYSection 4 of 13
Arterial Understanding the normal spinal cord vascular supply is essential to treating intramedullary spinal cord lesions; specifically because these vessels may have a variable and inconsistent distribution. The great vessels (aorta, carotids) contribute arterial supply to the spinal cord via segmental arteries, which further branch into medullary and radicular arteries. The radicular artery provides extramedullary blood supply to the nerve root and dura; the medullary artery bifurcates into anterior and posterior divisions to form the spinal arteries. One anterior and 2 posterior spinal arteries then transverse the longitudinal axis of the spinal cord and provide the blood supply to the spinal cord. Neoplasms acquire their blood supply by leaching blood from these vessels. Venous The venous plexus of the spinal column, termed the Batson plexus, is unlike other venous systems in the body because the veins do not contain valves. Therefore, blood can have pathologic retrograde flow. This retrograde flow blood can back up and cause venous congestion. This can manifest as venous hypertension. Because oxygenated blood cannot pass through the spinal cord because of the congestion of outflow, patients present with progressive neurologic dysfunction. Spinal cord The spinal cord parenchyma consists of a central canal surrounded by an H-shaped gray matter region that contains neurons. Outer myelinated nerve tracts, termed white matter, surround the central gray matter. The central canal represents an embryologic remnant from neurulation of the neural plate and is lined with ependymal cells. Ependymomas arise from these cells and, therefore, are typically located centrally in the spinal cord parenchyma. In contrast, astrocytes support gray matter neurons and white matter axons. Neoplastic transformation of these supporting cells results in the development of astrocytomas and may occur almost anywhere within the cord. CONTRAINDICATIONSSection 5 of 13
Observation with serial imaging studies over a variable period is a treatment option for patients who pose a high surgical risk, who are elderly, and/or who only have minimal neurologic signs. Patients in whom pathology tissue shows a malignant neoplasm may be best treated with radiotherapy because they are expected to have an accelerated deterioration and complete surgical resection is not possible. WORKUPSection 6 of 13
Lab Studies
Imaging Studies
Other Tests
Diagnostic Procedures
TREATMENTSection 7 of 13
Medical therapyPharmacological treatment of intramedullary spinal cord tumors is of limited benefit. High-dose intravenous corticosteroid therapy may improve neurologic function transiently but is not appropriate for long-term treatment. Although steroids decrease vasogenic edema, they do not treat the underlying pathologic condition. Prolonged use of steroids can be associated with gastric ulceration, hyperglycemia, and immunosuppression with cushingoid features. Chemotherapeutic regimens have limited success in the treatment of spinal cord neoplasms. This may be partly due to the inability of the chemotactic agents to cross the blood-brain barrier. Standard fractionated radiation is used for astrocytomas of residual and recurrent neoplasm. Surgical therapyPatients presenting with neurologic deficits and mass lesions in the spinal cord require histopathology in order to define the neoplasm such that treatment options can be maximized. The surgical approach to these lesions typically consists of preparing for gross total resection. The neoplasm is identified and then biopsy is performed. Surgery then proceeds based on the histology from the frozen specimen as well as the ability to define a surgical plane to resect the lesion. If the lesion is an astrocytoma, then the goal is debulking the tumor while not injuring the normal neural tracts. Ependymomas are attempted to be resected completely as long as a viable plane can be established and normal neural tracts are not disturbed. Preoperative detailsAny patient suspected of having an intrinsic spinal cord neoplasm should undergo a detailed history and physical examination. The preoperative evaluation should consist of a detailed neurologic examination and appropriate imaging studies to confirm the diagnosis. Detailed imaging studies should consist of MRI with and without gadolinium. If MRI is not available, myelography with CT scanning should be used. If appropriate, obtain a preoperative medical evaluation. Intraoperative detailsSurgical resection is performed with the patient under general anesthesia, typically in a prone position. Intraoperative neurophysiological monitoring provides real-time feedback regarding possible ischemia or retraction injury to the spinal cord during the resection and is used by some surgeons. A laminectomy (laminoplasty in children) is performed after radiographic confirmation of the appropriate spinal level. The laminectomy defect should be of sufficient size to allow visualization of healthy spinal cord above and below the suspected neoplasm. Using the intraoperative microscope or magnification, the spinal cord is inspected and the pia mater is opened directly over the tumor exposing the spinal cord. The spinal cord is incised sharply typically through the midline raphe. Once the tumor is exposed, a plane is established at the periphery. The goal for benign or low-grade neoplasms is gross total resection. Once the tumor-spinal cord interface is defined, the tumor can be debulked internally with gentle dissection or an ultrasonic cavitation to reduce spinal cord manipulation. Complete resection of benign neoplasms cannot always be achieved without neurological injury, particularly if the tumor–spinal cord interface is indistinct. Patients with biopsy-proven high-grade lesions typically have a rapid progression in neurological dysfunction, even after aggressive resections. Consequently, only biopsy and a dural patch graft (to enlarge the space for the spinal cord) may be an alternate approach to attempted resection. When surgical resection is completed, the dura and muscles are closed in layers. Postoperative detailsPatients are closely monitored in an ICU setting to monitor their neurologic examination and acutely detect and neurologic deterioration. Incisional pain should be minimal and should be relieved with intravenous analgesics. Patients typically have some degree of posterior column dysfunction due to traction and manipulation during surgery. This usually is in the form of "numbness" below the region of resection as well as proprioception difficulty. The proprioception difficulties can be disabling for the patients because they impair ambulation and fine motor control. These deficits tend to progressively improve with time. In Brotchi's series of 239 patients with low-grade spinal tumors, 5% of patients worsened, 50% of patients stabilized, and 40% of patients improved after surgical intervention.1 Overall, patients typically maintained their preoperative level of function postoperatively. Depending on the needs of patients, they are either discharged home or transferred to a rehabilitation facility. Follow-upFollow-up care should include serial neurologic examinations and MRI to monitor for recurrence or progressive growth of residual tumor. If patients experience any neurologic worsening, perform contrast-enhanced MRI. The recurrence rate for low-grade tumors is less than 5%; approximately 10% of patients have progression of residual tumor. Consider radiotherapy or stereotactic radiosurgery for the treatment of malignant neoplasms. Its role in benign neoplasms is unclear, but, typically, serial observation is recommended. COMPLICATIONSSection 8 of 13
OUTCOME AND PROGNOSISSection 9 of 13
The 5-year survival rate for patients with benign or low-grade spinal cord neoplasms is greater than 90%. A patient's overall prognosis depends on the neoplasm's histopathology. In Brotchi's series of 239 patients with low-grade spinal tumors and operative intervention, 5% worsened, 50% stabilized, and 40% improved.1 A patient's neurologic function after surgical intervention directly depended on his or her preoperative neurological status. Therefore, the goal of surgical treatment is to prevent further neurologic dysfunction from compression by the neoplasm, to obtain a diagnosis, and to potentially cure the neoplastic condition with a complete resection. FUTURE AND CONTROVERSIESSection 10 of 13
Intraoperative microscopy, neurophysiologic monitoring, and improved neuroimaging have improved the success of surgical intervention. Further advances in technology for tumor resection and neuroimaging may lead to further improvements in surgical outcomes. Better understanding of the genetics of these neoplasms may provide for earlier medical intervention with improved care and treatment of these disorders. Radiosurgical techniques, specifically the use of stereotactic radiosurgery, are improving such that these options will have an increased role in the treatment of benign disease and more aggressive neoplasms. ACKNOWLEDGMENTSSection 11 of 13
The authors and editors of eMedicine gratefully acknowledge the contributions of Jennifer Malone, MD, to the development and writing of this article. MULTIMEDIASection 12 of 13
REFERENCESSection 13 of 13
Spinal Cord Tumors: Management of Intradural Intramedullary Neoplasms excerpt Article Last Updated: Jul 1, 2008 | |||||||||||||||||||||||||||||||||
