William E. Krauss

Diagnosis and Treatment of Vertebral Column Metastases

The vertebral column is recognized as the most common site for bony metastases in patients with systemic malignancy. Patients with metastatic spinal tumors may present with pain, neurologic deficit, or both. Some tumors are asymptomatic and are detected during screening examinations. Treatment options include medical therapy, surgery, and radiation. However, diversity of patient condition, tumor pathology, and anatomical extent of disease complicate broad generalizations for treatment. Historically, surgery was considered the most appropriate initial therapy in patients with spinal metastasis with the goal of eradication of gross disease. However, such an aggressive approach has not been practical for many patients. Now, operative intervention is often palliative, with pain control and maintenance of function and stability the major goals. Surgery is reserved for neurologic compromise, radiation failure, spinal instability, or uncertain diagnosis. Recent literature has revealed that surgical outcomes have improved with advances in surgical technique, including refinement of anterior, lateral, posterolateral, and various approaches to the anterior spine, where most metastatic disease is located. We review these surgical approaches for which a team of surgeons often is needed, including neurosurgeons and orthopedic, general, vascular, and thoracic surgeons. Overall, a multimodality approach is useful in caring for these patients. It is important that clinicians are aware of the various therapeutic options and their indications. The optimal treatment of individual patients with spinal metastases should include consideration of their neurologic status, anatomical extent of disease, general health, age, and qualilty of life.

Prognosis and treatment of spinal cord astrocytoma.

PURPOSE To identify the prognostic factors for spinal cord astrocytoma and determine the effects of surgery and radiotherapy on outcome. METHODS AND MATERIALS This retrospective study reviewed the cases of consecutive patients with spinal cord astrocytoma treated at Mayo Clinic Rochester between 1962 and 2005. RESULTS A total of 136 consecutive patients were identified. Of these 136 patients, 69 had pilocytic and 67 had infiltrative astrocytoma. The median follow-up for living patients was 8.2 years (range, 0.08-37.6), and the median survival for deceased patients was 1.15 years (range, 0.01-39.9). The extent of surgery included incisional biopsy only (59%), subtotal resection (25%), and gross total resection (16%). Patients with pilocytic tumors survived significantly longer than those with infiltrative astrocytomas (median overall survival, 39.9 vs. 1.85 years; p < 0.001). Patients who underwent resection had a worse, although nonsignificant, median survival than those who underwent biopsy only (pilocytic, 18.1 vs. 39.9 years, p = 0.07; infiltrative, 19 vs. 30 months, p = 0.14). Postoperative radiotherapy, delivered in 75% of cases, gave no significant survival benefit for those with pilocytic tumors (39.9 vs. 18.1 years, p = 0.33) but did for those with infiltrative astrocytomas (24 vs. 3 months; Wilcoxon p = 0.006). On multivariate analysis, pilocytic histologic type, diagnosis after 1984, longer symptom duration, younger age, minimal surgical extent, and postoperative radiotherapy predicted better outcome. CONCLUSION The results of our study have shown that histologic type is the most important prognostic variable affecting the outcome of spinal cord astrocytomas. Surgical resection was associated with shorter survival and thus remains an unproven treatment. Postoperative radiotherapy significantly improved survival for patients with infiltrative astrocytomas but not for those with pilocytic tumors.

Surgical treatment of spinal dural arteriovenous fistulae: a consecutive series of 154 patients.

BACKGROUND:Embolization of spinal dural arteriovenous fistulae (SDVAFs) has emerged as an alternative to surgery. However, surgical disconnection is a simple and effective procedure. OBJECTIVE:To review results and complications of surgical treatment of 154 consecutive SDAVFs. METHODS:The records of 154 consecutive patients with SDAVFs were retrospectively reviewed. RESULTS:There were 120 males and 34 females (male/female ratio 3.5:1, mean age 63.6 years). The SDAVFs were located at the thoracic level in 92 patients and at the lumbar and sacral spine levels in 45 and 15 patients, respectively. The most common presenting symptoms were motor dysfunction (65 patients), sensory loss (31 patients), and paresthesias without sensory loss (13 patients). The mean interval from symptom onset to definitive diagnosis was 24.7 months (median 12 months). Surgery resulted in complete exclusion of the fistula at first attempt in 146 patients (95%). There were no deaths or major neurological complications related to the surgery. Six percent of patients experienced subjective or objective worsening of preoperative symptoms and signs by the time of discharge that persisted at follow-up. Other surgical complications consisted of wound infection in 2 patients and deep venous thrombosis in 3. Eight patients were lost to follow-up; 141 patients (96.6%) experienced improvement (120 patients, 82.2%) or stability (21 patients, 14.4%) of motor function at last follow-up compared with their preoperative status. Other symptoms such as numbness, sphincter dysfunction, and dysesthesias/neuropathic pain improved in 51.5%, 45%, and 32.6%, respectively. CONCLUSION:Surgical obliteration of SDAVFs is safe and very effective. Prognosis of motor function is favorable after surgical treatment.

Rheumatoid arthritis of the craniovertebral junction.

BACKGROUNDRheumatoid arthritis (RA) is the most common inflammatory disease involving the spine. It has a predilection for involving the craniocervical spine. Despite widespread involvement of the cervical spine with RA, few patients need surgery. The 3 major spinal manifestations of RA in the cervical spine are basilar invagination, atlantoaxial instability, and subaxial subluxations. Surgical management of RA involving the craniovertebral junction remains a challenge despite a decline in severe cases and an improvement in surgical techniques. METHODSWe conducted an exhaustive review of English-language publications discussing RA involving the craniovertebral junction. We paid special attention to publications detailing modern surgical management of these conditions. In addition, we outline our own surgical experience with such patients. RESULTSWe discuss alternative surgical methods for treating basilar invagination, atlantoaxial instability, and concurrent subaxial subluxations. We detail our surgical technique for transoral odontoidectomy, occipital cervical fusion, and atlantoaxial fusion. We detail the use of spinal surgical navigation in both of these procedures. CONCLUSIONSurgical management of RA remains a challenging field. There clearly has been a decrease in cases of mutilating RA involving the craniovertebral junction. Surgical techniques for managing these conditions have steadily improved.BACKGROUND Rheumatoid arthritis (RA) is the most common inflammatory disease involving the spine. It has a predilection for involving the craniocervical spine. Despite widespread involvement of the cervical spine with RA, few patients need surgery. The 3 major spinal manifestations of RA in the cervical spine are basilar invagination, atlantoaxial instability, and subaxial subluxations. Surgical management of RA involving the craniovertebral junction remains a challenge despite a decline in severe cases and an improvement in surgical techniques. METHODS We conducted an exhaustive review of English-language publications discussing RA involving the craniovertebral junction. We paid special attention to publications detailing modern surgical management of these conditions. In addition, we outline our own surgical experience with such patients. RESULTS We discuss alternative surgical methods for treating basilar invagination, atlantoaxial instability, and concurrent subaxial subluxations. We detail our surgical technique for transoral odontoidectomy, occipital cervical fusion, and atlantoaxial fusion. We detail the use of spinal surgical navigation in both of these procedures. CONCLUSION Surgical management of RA remains a challenging field. There clearly has been a decrease in cases of mutilating RA involving the craniovertebral junction. Surgical techniques for managing these conditions have steadily improved.

Total en bloc spondylectomy of C5 vertebra for chordoma.

Study Design. En bloc resection of a chordoma of the C5 vertebra with wide surgical margins. Objective. To present the surgical technique of total spondylectomy for a chordoma of the C5 vertebral body. Summary of Background Data. Malignant bone tumors require wide resection. Wide resection by total en bloc spondylectomy is difficult or not feasible for malignant vertebral tumors of the cervical spine due to the peculiar anatomic complexity of this region, including the vertebral arteries and the neural structures. There are no previous reports of en bloc resection of cervical spine tumors with wide surgical margins. Methods. Using staged posterior and anterior approaches, a total en bloc spondylectomy and spine arthrodesis was performed. En bloc excision of a C5 chordoma was achieved using a threadwire T-saw (Tomita and Kawahara, Kanazawa, Japan) with surgical margins free of tumor. The patient received postoperative adjuvant proton beam radiation therapy. Results. The patient remains disease-free 9 years after the operation. Conclusion. Total en bloc spondylectomy with wide surgical margins is feasible for malignant bone tumors of the cervical spine.

Spinal cord biopsy: a review of 38 cases.

OBJECTIVENeurosurgeons are frequently asked to evaluate patients for spinal cord biopsies when preoperative magnetic resonance imaging studies demonstrate nonspecific features. These lesions often appear unresectable, but surgeons must decide whether a biopsy is warranted. To determine the best approach to these cases, we evaluated the clinicopathological findings for patients with unknown spinal cord lesions who underwent spinal cord biopsies. METHODSThirty-eight consecutive patients who underwent spinal cord biopsies at the Mayo Clinic (Rochester, MN) between August 1988 and July 1998 were studied. A detailed review of the case histories, radiological results, surgical notes, histological findings, and outcomes was performed. RESULTSSpinal cord biopsies were performed for 21 male and 17 female patients (mean age, 42.1 yr) with progressive neurological deficits related to spinal cord lesions. All patients underwent preoperative magnetic resonance imaging evaluations. High T2-weighted signal intensity and spinal cord expansion were identified in 92 and 87% of cases, respectively. After gadolinium infusion, the majority (94%) of the inflammatory lesions demonstrated patchy and often peripherally situated enhancement. This neuroradiological pattern was less common for neoplasms (50%) and benign lesions (40%). The most common pathological findings were inflammatory changes of demyelination or sarcoidosis, which together accounted for 13 cases (34%). Nonspecific changes or benign lesions were observed in 10 cases (26%). Neoplasms were identified in eight cases (21%). One case of tuberculosis and one of schistosomiasis were found. Overall, 47% of the preoperative diagnoses made by the attending surgeon were correct. For 26% of the patients, specific treatment was based on the biopsy results. The average follow-up period was 12 months (standard deviation, 14 mo; range, 0–50 mo). CONCLUSIONPreoperative laboratory and imaging studies are often diagnostically inconclusive in cases of spinal cord lesions with nonspecific features. Biopsies should be considered for patients with progressive symptomatic lesions.

Venous congestive myelopathy: a mimic of neoplasia

Venous congestive myelopathy is a progressive disorder frequently associated with arteriovenous fistulas, usually dural. By causing diffuse spinal cord enlargement and enhancement on imaging, it may simulate a neoplasm and prompt a biopsy. We evaluated the biopsy findings in seven such patients (M=5, F=2, mean age 59±11 years) who presented variably with progressive lower extremity weakness (86%), bowel and bladder dysfunction (86%), sensory changes (86%) or pain (29%). Preoperative magnetic resonance imaging showed spinal cord enlargement with T2-hyperintensity (86%) and contrast enhancement (57%) at the cervical (14%), thoracolumbar (57%), and/or conus medullaris (57%) level. Prebiopsy spinal angiogram, performed in two patients, was negative. Spinal cord biopsy showed architecturally distorted parenchyma with gliosis and thick hyalinized vessels (100%), variable myelin loss (71%), mild glial atypia (57%), hemosiderin deposition (71%), Rosenthal fibers (43%), vascular thrombosis (29%), and necrosis (29%), features highly suggestive of venous congestive myelopathy. Postbiopsy spinal angiograms were performed in five patients. A dural arteriovenous fistula was identified by selective angiography in three patients, including the two with a negative preoperative angiogram. Additional postbiopsy angiographic studies in two patients were negative, and two patients were followed up without angiography. Mean follow-up after biopsy was 13.6 months. Histologic changes characteristic of venous congestive myelopathy may be seen in spinal cord biopsies with or without an associated fistula. Recognition of this entity by surgical pathologists is important, leading to the correct identification of a non-neoplastic lesion as well as of a surgically treatable disease.

Juxtafacet Cysts of the Cervical Spine

OBJECTIVE We report a retrospective series of 13 patients who presented with symptoms and signs caused by cervical juxtafacet cysts. Clinical findings, radiographic features, surgical management strategies, and possible causes are reported and discussed. METHODS We reviewed clinical histories, radiographic studies, surgical notes, and pathological records of all 13 patients who underwent surgery for subaxial cervical juxtafacet cysts from 1984 to 1997 at the Mayo Clinic in Rochester, MN. During the summer of 1997, surgical outcomes were assessed by direct or telephone interview. RESULTS Nine patients were men and four were women. The average age at the time of presentation was 66 years. One patient had undergone a previous anterior cervical fusion below the level of the cyst. Ten patients presented with radiculopathies. Two patients presented with myeloradiculopathies. One patient presented with a cervical myelopathy. Computed tomographic myelography and magnetic resonance imaging were essential in establishing a preoperative diagnosis. The cysts were located at C7-T1 in nine patients, at C4-C5 in two patients, at C6-C7 in one patient, and at C3-C4 in one patient. All patients underwent posterior laminectomy or hemilaminectomy, excision of the cyst, and decompression of the thecal sac and/or nerve root. Two patients underwent concurrent posterior fusion procedures for instability. All patients experienced good to excellent relief of their radicular pain. All three myelopathies stabilized after surgery. There were no major complications or recurrences. CONCLUSION Juxtafacet cysts seem to be a degenerative change of the cervical spine rather than a traumatic event. Similar to their counterparts in the lumbar spine, they tend to arise in segments with increased mobility. Surgical treatment is effective.

Nonenhancing tumors of the spinal cord

OBJECT Enhancement of pathological entities in the central nervous system is a common finding when the blood-brain barrier has been compromised. In the brain, the presence or absence of gadolinium enhancement is often an indicator of tumor invasiveness and/or grade. In the spinal cord, however, contrast enhancement has been shown in all tumor types, regardless of grade. In this study the authors explore the incidence of nonenhancing tumors of the spinal cord and the clinical course of patients with these lesions. METHODS A retrospective analysis was conducted in which investigators examined the patterns of enhancement of histologically proven intramedullary spinal cord tumors that had been evaluated at the Mayo Clinic between 1998 and 2002. The tumors that did not enhance were the subject of this report. RESULTS A total of 130 patients with intramedullary tumors were evaluated. Of those, 11 patients (9%) had tumors that did not enhance. Histologically, a majority of tumors were astrocytomas (eight low-grade and two high-grade lesions); one tumor was a subependymoma. Morphologically, most of the tumors were diffuse and none had associated cysts. Tumors spanned from two to seven levels and were located throughout the spinal cord (four cervical, three cervicothoracic, one thoracic, and three thoracolumbar). Biopsy procedures were performed in eight patients, subtotal resection was performed in two, and gross-total resection in one. After a mean follow-up period of 19 months, tumors remained stable in eight patients but progressed in three, two of whom died. CONCLUSIONS A number of intramedullary spinal cord tumors will not enhance after addition of contrast agents. The absence of enhancement does not imply the absence of tumor.

Cystic deterioration of the C1–2 articulation: clinical implications and treatment outcomes

OBJECT Synovial cysts of the cervical spine are rare. Further, synovial cysts of the C1-2 articulation, or retroodontoid cysts, are very rare, with fewer than 20 cases reported overall. The authors report on a single-institution series of 10 patients with C1-2 retroodontoid synovial cysts. METHODS The charts of 10 patients with pathologically confirmed synovial cysts following resection between January 1998 and June 2009 were reviewed. The clinical presentation, radiographic findings, surgical management, and pre- and postoperative functional levels (reported as a modified Rankin outcome) are reported. RESULTS All 10 patients underwent attempts at complete resection of the synovial cyst; none of the lesions were simply aspirated. All 4 patients with an initial recommendation of observation alone ultimately underwent surgery because of their swift neurological deterioration. The mean age at surgery was 75.4 ± 4.6 years (range 54-81 years). The mean presenting cyst volume was 4.6 ± 1.7 cm(3). Nine of 10 patients underwent transoral resection of the cyst with posterior fusion. Six of the 10 patients underwent additional posterior laminectomy for decompression. The hospital length of stay varied from 2 to 45 days, with a mean of 19 ± 7 days. All patients undergoing transoral decompression had varying degrees of difficulty with postoperative dysphagia, diagnosed using videofluoroscopy. All patients improved in their modified Rankin Scale score after surgical intervention with a mean follow-up of 42 months (95% CI 12-72 months). CONCLUSIONS Synovial cysts of the atlantoaxial joint are rare. They occur in older patients in whom clinical deterioration is likely to occur. In most cases, these cysts can be diagnosed preoperatively. Transoral decompression with posterior fusion is an effective treatment for C1-2 degenerative cysts and can be accomplished with few complications. However, the ideal treatment for these lesions remains unknown.