Faculty Bibliography

OBJECT In this paper, the authors' goal was to determine the outcome of reoperation for recurrent epidural spinal cord compression in patients with metastatic spine disease. METHODS A retrospective chart review was conducted of all patients who underwent spine surgery at the Memorial Sloan-Kettering Cancer Center between 1996 and 2007. Thirty-nine patients who underwent reoperation of the spine at the level previously treated with surgery were identified. Only patients whose reoperation was performed because of tumor recurrence leading to high-grade epidural spinal cord compression or recurrence with no further radiation options were included in the study. Patients who underwent reoperations exclusively for instrumentation failure were excluded. All patients underwent additional decompression via a posterolateral approach without removal of the spinal instrumentation. RESULTS Patients underwent 1-4 reoperations at the same level. A median survival time of 12.4 months was noted after the first reoperation, and a median survival time of 9.1 months was noted after the last reoperation. At last follow-up 22 (65%) of 34 patients were ambulatory at the time of last follow-up or death, and the median time between loss-of-ambulation and death was 1 month. Functional status was maintained or improved by one Eastern Cooperative Oncology Group grade in 97% of patients. A major surgical complication rate of 5% was noted. CONCLUSIONS Reoperation represents a viable option in patients with high-grade epidural spinal cord compression who have recurrent metastatic tumors at previously operated spinal levels. In carefully selected patients, reoperation can prolong ambulation and result in good functional and neurological outcomes.

OBJECTIVE:The evolution of imaging techniques, along with highly effective radiation options has changed the way metastatic epidural tumors are treated. While high-grade epidural spinal cord compression (ESCC) frequently serves as an indication for surgical decompression, no consensus exists in the literature about the precise definition of this term. The advancement of the treatment paradigms in patients with metastatic tumors for the spine requires a clear grading scheme of ESCC. The degree of ESCC often serves as a major determinant in the decision to operate or irradiate. The purpose of this study was to determine the reliability and validity of a 6-point, MR imaging-based grading system for ESCC. METHODS:To determine the reliability of the grading scale, a survey was distributed to 7 spine surgeons who participate in the Spine Oncology Study Group. The MR images of 25 cervical or thoracic spinal tumors were distributed consisting of 1 sagittal image and 3 axial images at the identical level including T1-weighted, T2-weighted, and Gd-enhanced T1-weighted images. The survey was administered 3 times at 2-week intervals. The inter- and intrarater reliability was assessed. RESULTS:The inter- and intrarater reliability ranged from good to excellent when surgeons were asked to rate the degree of spinal cord compression using T2-weighted axial images. The T2-weighted images were superior indicators of ESCC compared with T1-weighted images with and without Gd. CONCLUSIONS:The ESCC scale provides a valid and reliable instrument that may be used to describe the degree of ESCC based on T2-weighted MR images. This scale accounts for recent advances in the treatment of spinal metastases and may be used to provide an ESCC classification scheme for multicenter clinical trial and outcome studies.

STUDY DESIGN/METHODS:Systematic review and evidence appraisal. OBJECTIVE:To evaluate the optimal treatment for patients with spinal cord compression secondary to solid metastases and in patients with solitary renal metastases, without spinal cord compression. METHODS:Focused Medline and OVID database searches were conducted using relevant keywords. Only clinical articles that evaluated specific end points of interest were included in the literature review. The quality of evidence provided by each article was assessed using the ATS guidelines. The expert opinion was synthesized based on the evidence and rated as strong or weak, depending on the quality of the supporting literature. RESULTS:Twelve surgical and 7 radiation clinical series were identified that evaluated post-treatment ambulation in patients with metastatic spinal cord compression. Only 1 surgical article met the criteria for moderate quality evidence while the remaining surgical and radiation articles presented very low quality of evidence. All articles that evaluated treatment of solitary renal metastases presented very low quality of evidence. CONCLUSION/CONCLUSIONS:A strong recommendation is made for patients with high-grade cord compression due to solid tumor metastases to undergo surgical decompression with stabilization followed by radiation therapy. A weak recommendation is made for patients with solitary renal metastases without spinal cord compression to undergo spinal stereotactic radiosurgery.

PURPOSE/OBJECTIVE:Single-fraction image-guided intensity-modulated radiation therapy (IG-IMRT) allows for tumoricidal treatment of traditionally radioresistant cancers while sparing critical adjacent structures. Risk of vertebral fracture after IG-IMRT for spinal metastases has not been defined. PATIENTS AND METHODS/METHODS:We evaluated 62 consecutive patients undergoing single fraction IG-IMRT at 71 sites for solid organ metastases. A neuroradiologist and three spine surgeons evaluated prospectively obtained magnetic resonance/computed tomography (CT) imaging studies for post-treatment fracture development and tumor recurrence. RESULTS:Fracture progression was noted in 27 vertebrae (39%). Multivariate logistic regression analysis showed that CT appearance, lesion location, and percent vertebral body involvement independently predicted fracture progression. Lesions located between T10 and the sacrum were 4.6 times more likely to fracture than were lesions above T10 (95% CI, 1.1 to 19.7). Lytic lesions were 6.8 times more likely to fracture than were sclerotic and mixed lesions (95% CI, 1.4 to 33.3). As percent vertebral body involvement increased, odds of fracture also increased. Patients with fracture progression had significantly higher narcotic use, change in Karnofsky performance score, and a strong trend toward higher pain scores. Local tumor progression occurred in seven patients and contributed to one fracture. Obesity, posterior element involvement, bisphosphonate use, and local kyphosis did not confer increased risk. CONCLUSION/CONCLUSIONS:Vertebral fracture is common after single fraction IG-IMRT for metastatic spine lesions. Lytic disease involving more than 40% of the vertebral body and location at or below T10 confer a high risk of fracture, the presence of which yields significantly poorer clinical outcomes. These results may help clinicians identify high-risk patients who would benefit from prophylactic vertebro- or kyphoplasty.

OBJECTIVE:To determine the accuracy of [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the diagnosis of vertebral metastases in patients with cancer using needle-biopsy results and patient follow-up data. METHODS:A retrospective chart review of all patients who underwent a needle biopsy of a spinal lesion and underwent FDG-PET within 6 weeks of the biopsy was performed. Biopsy results and magnetic resonance imaging and computed tomographic appearance of the biopsied lesion, as well as long-term clinical follow-up data, were recorded for each patient. A total of 82 patients with solid tumors and hematological spine metastases were included in this study. RESULTS:The mean standardized uptake values of lesions with active cancer were 7.1 and 2.1 in benign lesions (P < 0.02). In patients with metastatic solid tumors, the mean standardized uptake value was 7.3. Stratification of solid tumor lesions according to whether they had a sclerotic appearance on computed tomographic scans showed that FDG-PET was a significantly better predictor of cancer status in lytic or mixed lesions. In patients with a history of solid tumors, there was 100% concordance between the FDG-PET and needle-biopsy diagnoses in nonsclerotic lesions, when the standardized uptake value cutoff of 2 was used. CONCLUSION/CONCLUSIONS:FDG-PET is an accurate screening test for vertebral metastases in cancer patients. It is especially accurate in patients with nonsclerotic vertebral lesions and a history of solid malignancy.

Malignant primary tumors of the spine present difficult management problems because of the complexities of en bloc resection and their chemoresistance and radioresistance. A combination of radiation techniques and advances in systemic therapy may ultimately provide improved local tumor control and cure for these treatment-resistant tumors.

The authors report a case of a nonachondroplastic dwarf with severe basilar invagination and compression of the cervicomedullary junction (CMJ) due to juvenile rheumatoid arthritis. Initially excellent reduction of the invagination and decompression of the CMJ was achieved using posterior fixation. However, 1 month postoperatively symptoms recurred and the authors found imaging evidence of recurrence as well. The patient subsequently underwent an endoscopic transnasal resection of the dens with assistance of Iso-C navigation. He recovered well and tolerated regular diet on postoperative Day 2.

Chiari malformations may present with a wide range of symptoms and signs. Nevertheless, focal foot weakness as a presentation of a Chiari malformation has not been described in the pediatric neurosurgical literature. Two children with Chiari malformations and holocord syringomyelia presented with manifestations of a supposed isolated lumbar radiculopathy. Neurological deficits completely resolved after decompressive suboccipital craniectomy and cervical laminectomy. These cases emphasize the importance of imaging the entire craniospinal axis and avoidance of therapeutic intervention specifically aimed at a radiculopathic process when initial imaging fails to show a structural abnormality at the spinal level of deficit. The possible pathophysiological origins for this unusual presentation are discussed. Based on the experience gained with these patients, recommendations are made regarding the diagnostic workup and management of this entity in children presenting with focal deficits that are not supported by imaging of the affected root levels. Chiari malformations may rarely masquerade as lower motor and sensory deficits, and appropriate treatment may result in excellent recovery of function.

OBJECT: In this retrospective analysis the authors describe the assessment and outcomes of 90 patients who underwent placement of posterior instrumentation at the cervicothoracic junction following the resection of a primary or metastatic tumor during a 10-year period. METHODS: All patients underwent a posterolateral laminectomy including uni- or bilateral facetectomy, and 44 patients additionally required vertebral body resection and reconstruction. In patients who underwent C-6 or C-7 decompression, the posterior instrumentation strategies changed from the use of lateral mass plate systems (LMPSs) to lateral mass screw/rod systems (LMSRSs). Similarly, for T1-3 tumor decompression, the strategy shifted from sublaminar hook/rod systems (SHRSs) to the use of pedicle screw systems (PSSs) in which the surgeon used either a 6.25-mm rod or dual-diameter rods with or without a connector. RESULTS: The overall surgical complication rate was 19% including fixation failure in 11 patients (12%), 6 of whom required reoperation. Fixation failure rates for cervical decompression decreased from 2 (29%) of 7 patients in the LMPS group to 0 (0%) of 8 in the LMSRS group (p = 0.2). The fixation failure rates for thoracic decompression were 7 (15%) of 48 patients in the SHRS group, and there was a decrease to 2 (7%) of 27 in the PSS group (p = 0.48). Neurological and functional outcomes including American Spinal Injury Association, Eastern Cooperative Oncology Group, and Medical Research Council muscle strength and pain scores remained stable or improved in 94, 96, 100, and 96% of patients, respectively. CONCLUSIONS: Current posterior instrumentation strategies involving LMSRSs and PSSs provide excellent and safe stabilization of the cervicothoracic junction following resection of primary or metastatic tumors