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Russell R. Lonser, Robert J. Weil, John E. Wanebo, Hetty L. Devroom and Edward H. Oldfield

Object. Von Hippel—Lindau (VHL) disease is an autosomal-dominant disorder frequently associated with hemangioblastomas of the spinal cord. Because of the slow progression, protean nature, and high frequency of multiple spinal hemangioblastomas associated with VHL disease, the surgical management of these lesions is complex. Because prior reports have not identified the factors that predict which patients with spinal cord hemangioblastomas need surgery or what outcomes of this procedure should be expected, the authors have reviewed a series of patients with VHL disease who underwent resection of spinal hemangioblastomas at a single institution to identify features that might guide surgical management of these patients.

Methods. Forty-four consecutive patients with VHL disease (26 men and 18 women) who underwent 55 operations with resection of 86 spinal cord hemangioblastomas (mean age at surgery 34 years; range 20–58 years) at the National Institutes of Health were included in this study (mean clinical follow up 44 months). Patient examination, review of hospital charts, operative findings, and magnetic resonance imaging studies were used to analyze surgical management and its outcome. To evaluate the clinical course, clinical grades were assigned to patients before and after surgery. Preoperative neurological status, tumor size, and tumor location were predictive of postoperative outcome. Patients with no or minimal preoperative neurological dysfunction, with lesions smaller than 500 mm3, and with dorsal lesions were more likely to have no or minimal neurological impairment. Syrinx resolution was the result of tumor removal and was not influenced by whether the syrinx cavity was entered.

Conclusions. Spinal cord hemangioblastomas can be safely removed in the majority of patients with VHL disease. Generally in these patients, hemangioblastomas of the spinal cord should be removed when they produce symptoms or signs.

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Russell R. Lonser, Robert J. Weil, Paul F. Morrison, Lance S. Governale and Edward H. Oldfield

Object. Although many macromolecules have treatment potential for peripheral nerve disease, clinical use of these agents has been restricted because of limitations of delivery including systemic toxicity, heterogeneous dispersion, and inadequate distribution. In an effort to overcome these obstacles, the authors examined the use of convection to deliver and distribute macromolecules into peripheral nerves.

Methods. For convective delivery, the authors used a gas-tight, noncompliant system that provided continuous flow through a small silica cannula (inner diameter 100 µm, outer diameter 170 µm) inserted into a peripheral nerve. Increases in the volume of infusion (Vi) (10, 20, 30, 40, and 80 µl) of 14C-labeled (nine nerves) or gadolinium-labeled (two nerves) albumin were infused unilaterally or bilaterally into the tibial nerves of six primates (Macaca mulatta) at 0.5 µl/minute. The volume of distribution (Vd), percentage recovery, and delivery homogeneity were determined using quantitative autoradiography, an imaging program developed by the National Institutes of Health, magnetic resonance (MR) imaging, scintillation counting, and kurtosis (K) analysis. One animal that was infused bilaterally with gadolinium-bound albumin (40 µl to each nerve) underwent MR imaging and was observed for 16 weeks after infusion.

The Vd increased with the Vi in a logarithmic fashion. The mean Vd/Vi ratio over all Vi was 3.7 ± 0.8 (mean ± standard deviation). The concentration across the perfused region was homogeneous (K = −1.07). The infusate, which was limited circumferentially by the epineurium, followed the parallel arrangement of axonal fibers and filled long segments of nerve (up to 6.8 cm). Recovery of radioactivity was 75.8 ± 9%. No neurological deficits arose from infusion.

Conclusions. Convective delivery of macromolecules to peripheral nerves is safe and reliable. It overcomes obstacles associated with current delivery methods and allows selective regional delivery of putative therapeutic agents to long sections of nerve. This technique should permit the development of new treatments for numerous types of peripheral nerve lesions.

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Robert J. Weil, Russell R. Lonser, Hetty L. Devroom, John E. Wanebo and Edward H. Oldfield

Object. Hemangioblastomas of the brainstem constitute 5 to 10% of central nervous system (CNS) tumors in patients with von Hippel—Lindau (VHL) disease. At present, optimal management of brainstem hemangioblastomas associated with VHL disease is incompletely defined. In an attempt to clarify some of the uncertainty about the operative treatment of these lesions and its outcome, the authors reviewed all cases of VHL disease in which resection of brainstem hemangioblastomas was performed at the National Institutes of Health during a 10-year period.

Methods. Twelve consecutive patients with VHL disease (six male and six female patients [mean age 31.7 ± 9 years; range 15–46 years]) who underwent 13 operations to remove 17 brainstem hemangioblastomas were included in this study (mean follow-up period, 88.4 ± 37.4 months; range 37–144 months). Serial examinations, hospital charts, magnetic resonance images, and operative records were reviewed. To evaluate clinical course, clinical grades were assigned to each patient before and after surgery.

Preoperative neurological function was the best predictor of long-term outcome. In addition, patients who underwent CNS surgeries for hemangioblastomas were more likely to improve or to remain neurologically stable. Tumor or cyst size, the presence of a cyst, or the location of the tumor (intramedullary, extramedullary, or mixed; posterior medullary, obex, or lateral) did not affect outcome. No patient was neurologically worse after brainstem surgery. At long-term follow-up review (mean 88.4 months), only one patient had declined neurologically and this was due to the cumulative neurological effects caused by eight additional hemangioblastomas of the spinal cord and their surgical treatment.

Conclusions. Brainstem hemangioblastomas in patients with VHL disease can be removed safely; they generally should be resected when they become symptomatic or when the tumor has reached a size such that further growth will increase the risks associated with surgery, or in the presence of an enlarging cyst. Magnetic resonance imaging is usually sufficient for preoperative evaluation and presurgical embolization is unnecessary. The goal of surgery is complete resection of the lesion before the patient experiences a disabling neurological deficit.

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Robert J. Weil, Alexander O. Vortmeyer, Zhengping Zhuang, Svetlana D. Pack, Nicholas Theodore, Robert K. Erickson and Edward H. Oldfield

✓ Hemangioblastomas of the central nervous system (CNS) may occur sporadically or in association with von Hippel—Lindau (VHL) syndrome. The authors present four patients with no family history or clinical evidence of VHL syndrome in whom extensive, progressive, en plaque coating of the brainstem and spinal cord with hemangioblastomas developed 1 to 8 years after complete resection of a solitary cerebellar hemangioblastoma.

Analysis included detailed physical, biochemical, radiological, and pathological examinations in all four patients, combined with family pedigree analysis. In addition, a detailed investigation of the VHL gene was undertaken. Allelic loss, comparative genomic hybridization (CGH), single-stranded conformational polymorphism screening, CpG island methylation status, and X chromosome inactivation clonality analyses were performed. Although there was no evidence of germline alterations in the VHL gene on clinical and radiological examination or in the family history (all four patients) or analysis of peripheral blood (three patients), somatic deletion of one copy of the VHL gene occurred in these tumors. These findings indicate that the multiple, separate deposits of tumors were likely derived from a single clone. Results of CGH indicate that one or several additional genes are probably involved in the malignant behavior of the hemangioblastomas in these patients. Furthermore, the malignant biological and clinical behavior of these tumors, in which multiple sites of subarachnoid dissemination developed 1 to 8 years after initial complete resection, followed by progressive tumor growth and death of the patients, occurred despite a histological appearance typical of benign hemangioblastomas.

Malignant hemangioblastomatosis developed 1 to 8 years after resection of an isolated cerebellar hemangioblastoma. Alterations of the VHL gene may be permissive in this setting, but other genes are likely to be the source of the novel biological and clinical presentation of the disseminated hemangioblastomas in these patients. This appears to represent a novel condition in which the product of one or more mutations in several genes permits malignant tumor behavior despite retention of a benign histological picture, a circumstance previously not recognized in CNS tumors.

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Robert J. Weil, Zhengping Zhuang, Svetlana Pack, Shimareet Kumar, Lee Helman, Brian G. Fuller, Crystall L. Mackall and Edward H. Oldfield

✓ Molecular biological techniques have begun to transform modern medicine. These techniques have shown promise in the pathological diagnosis of difficult or uncommon tumors. Accurate molecular diagnosis of the small round-cell tumors, for example, is especially important because divergent therapies may be required to eradicate such disparate lesions as neuroblastoma, lymphoma, rhabdomyosarcoma, central primitive neuroectodermal tumors/medulloblastoma, or Ewing sarcoma (ES). The authors present an unusual case of a primary, extraosseous ES arising from the intramedullary spinal cord, in which molecular studies were required for specific diagnosis and therapeutic guidance.

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Oral Presentations

2010 AANS Annual Meeting Philadelphia, Pennsylvania May 1–5, 2010