Faculty Bibliography

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

OBJECT/OBJECTIVE:The extended transsphenoidal approach is a less invasive method for removing purely suprasellar lesions compared with traditional transcranial approaches. Most advocates have used a sublabial incision and a microscope and have reported a significant risk of cerebrospinal fluid (CSF) leakage. The authors report on a series of purely endoscopic endonasal surgeries for resection of suprasellar supradiaphragmatic lesions above a normal-sized sella turcica with a low risk of CSF leakage. METHODS:A purely endoscopic endonasal approach was used to remove suprasellar lesions in a series of 10 patients. Five lesions were prechiasmal (three tuberculum sellae and two planum sphenoidale meningiomas) and five were post-chiasmal (four craniopharyngiomas and one Rathke cleft cyst). The floor of the planum sphenoidale and the sella turcica was reconstructed using a multilayer closure with autologous and synthetic materials. Spinal drainage was performed in only five cases. Complete resection of the lesions was achieved in all but one patient. The pituitary stalk was preserved in all but one patient, whose stalk was invaded by a craniopharyngioma and who had preoperative diabetes insipidus (DI). Vision improved postoperatively in all patients with preoperative impairment. Six patients had temporary DI; in five, the DI became permanent. Four patients with craniopharyngiomas required cortisone and thyroid replacement. After a mean follow up of 10 months, there was only one transient CSF leak when a lumbar drain was clamped prematurely on postoperative Day 5. CONCLUSIONS:A purely endoscopic endonasal approach to suprasellar supradiaphragmatic lesions is a feasible minimally invasive alternative to craniotomy. With a multilayer closure, the risk of CSF leakage is low and lumbar drainage can be avoided. A larger series will be required to validate this approach.

BACKGROUND CONTEXT/BACKGROUND:Paragangliomas are neuroendocrine tumors that most frequently arise in the adrenal medulla, carotid body, and glomus jugulare. However, they have been reported in many other sites throughout the body. Within the central nervous system, the overwhelming majority of paragangliomas arise intradurally in the area of the cauda equina. We report a case of a woman who presented with back pain and radiculopathy and was found to have an intraosseous sacral mass on magnetic resonance imaging (MRI). Operative biopsy revealed that this lesion was a paraganglioma. Chest, abdomen, and pelvis computed tomography scans revealed no other tumors. This lesion was treated with limited resection, decompression, stabilization, and radiation therapy. PURPOSE/OBJECTIVE:To report a rare case of an intrasacral paraganglioma that presented with back pain and radiculopathy and was treated with intralesional decompression, stabilization, and radiation. STUDY DESIGN/METHODS:Observational case report. METHODS:A 69-year-old woman presented with back and leg pain. An MRI scan revealed a grade II spondylolisthesis at L5/S1 and a left-sided intraosseus mass at S1 with significant obstruction of the left S1 nerve root foramen. The patient underwent initially an open biopsy of this lesion that revealed a paraganglioma. Subsequently, she underwent transarterial embolization of this lesion, partial resection with decompression of the nerve root, and stabilization and arthrodesis from L4 to the ilium. RESULTS:Intraoperatively, a highly vascular lesion was encountered. The patient's back and leg pain improved significantly after surgery. She was referred for intensity-modulated radiation therapy. One year after surgery, she was neurologically intact without evidence of growth of the lesion. CONCLUSIONS:Only two cases of primary intraosseous sacral paragangliomas were reported in the past. We believe that paragangliomas should be included in the differential diagnosis of intraosseous sacral tumors. Optimal treatment of the lesions can be difficult because of their hypervascular nature and the high morbidity associated with complete surgical resection. Treatment should combine preoperative embolisation, surgical resection if possible, and radiation therapy.

OBJECTIVE:Oxidative damage has been implicated in the pathogenesis of cerebral ischemia. We previously demonstrated that exogenously supplied dehydroascorbic acid (DHA), an oxidized, blood-brain barrier transportable form of the antioxidant ascorbic acid (AA), improves outcome after experimental stroke. METHODS:To investigate the neuroprotective effect of DHA therapy, we measured cerebral AA levels using a novel assay, quantified markers of lipid peroxidation, and evaluated infarct volume after reperfused stroke in a murine model. All experiments were performed using a new citrate/sorbitol-stabilized DHA formulation to improve the stability of the compound. RESULTS:Intraparenchymal AA levels declined after cerebral ischemia/reperfusion and were repleted in a dose-dependent fashion by postischemic administration of intravenous DHA (P < 0.01). Repletion of these levels was associated with reductions in cerebral malondialdehyde levels (P < 0.05), which were also elevated after reperfused stroke. DHA repletion of interstitial AA levels and reduction in cerebral lipid peroxidation was associated with dose-dependent reductions in infarct volume (P < 0.05). CONCLUSION/CONCLUSIONS:Together, these results indicate that an intravenous cerebroprotective dose of citrate/sorbitol-stabilized DHA is correlated with increased brain ascorbate levels and a suppression of excessive oxidative metabolism.

The complement cascade has been implicated in ischemia/reperfusion injury, and recent studies have shown that complement inhibition is a promising treatment option for acute stroke. The development of clinically useful therapies has been hindered, however, by insufficient understanding of which complement subcomponents contribute to post-ischemic injury. To address this issue, we subjected mice deficient in selected complement proteins (C1q, C3, C5) to transient focal cerebral ischemia. Of the strains investigated, only C3-/- mice were protected, as demonstrated by 34% reductions in both infarct volume (P<0.01) and neurological deficit score (P<0.05). C3-deficient mice also manifested decreased granulocyte infiltration (P<0.02) and reduced oxidative stress (P<0.05). Finally, administration of a C3a-receptor antagonist resulted in commensurate neurological improvement and stroke volume reduction (P<0.05). Together, these results establish C3 activation as the key constituent in complement-related inflammatory tissue injury following stroke and suggest a C3a anaphylatoxin-mediated mechanism.