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  • Author or Editor: Alan R. Cohen x
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Endoscopic treatment of colloid cysts of the third ventricle

Technical note and review of the literature

M. Samy Abdou and Alan R. Cohen

✓ The surgical technique for the endoscopic evacuation of colloid cysts of the third ventricle in 13 patients is described. The authors conclude that endoscopic resection of these lesions is a useful addition to the current surgical repertoire and a viable alternative to stereotactic aspiration or open craniotomy.

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Carl B. Heilman and Alan R. Cohen

✓ The fiberoptic endoscope has never gained popularity among neurosurgeons although it is ideally suited for navigating within the cerebral ventricles. Recent advances in optics and miniaturization make the application of endoscopy in neurosurgery more practical. The authors report eight children who underwent ventriculoscopic fenestration of symptomatic loculated cerebrospinal fluid (CSF) collections. These CSF collections were either isolated ventricular cysts or trapped lateral ventricles secondary to obstruction at the foramen of Monro. Cyst wall dissection was carried out with a “saline torch” dissector which was introduced through a working channel in the ventriculoscope. The torch was used to coagulate vessels and to sculpt large windows in cyst walls or in the septum pellucidum. Ventriculoscope-guided cyst fenestration can be performed safely and easily under direct vision. The technique may permit simplification of shunt systems in some patients and elimination of shunts in others.

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Robin F. Koeleveld and Alan R. Cohen

✓ A case of primary embryonal-cell carcinoma of the parietal lobe is reported. The unusually chronic presentation of such a malignant tumor is described. The atypical computerized tomography and magnetic resonance imaging characteristics of this lesion are presented. Review of the literature yielded no previous reports of a lobar embryonal-cell carcinoma. The rarity of intracranial germ-cell tumors presenting off the midline is discussed.

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Alan R. Cohen

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Alan R. Cohen, Slobodan Aleksic and Joseph Ransohoff

✓ The authors report an unusual complication related to a dural substitute. An inflammatory response to a Marlex mesh duraplasty simulated a recurrent convexity meningioma 20 years after the initial surgery.

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Shervin R. Dashti, Shenandoah Robinson, Mark Rodgers and Alan R. Cohen

✓Tuberous sclerosis complex is a genetic disorder characterized by the development of hamartomas in multiple organs including the brain, skin, eye, kidney, and heart. Neurological features include seizures and mental retardation. Cortical tubers and subependymal nodules are the characteristic intracranial lesions of tuberous sclerosis. Subependymal giant cell astrocytomas, typically located adjacent to the foramen of Monro, can enlarge and cause symptomatic ventricular obstruction.

The authors describe the case of a 3-year-old boy with a history of tuberous sclerosis and retinal lesions who presented with an enlarging enhancing pineal region mass. Via an infratentorial supracerebellar approach, the mass was removed using both the operative microscope and a rigid neuroendoscope. Pathological examination showed a giant cell astrocytoma. To the authors' knowledge, this is the first reported case of tuberous sclerosis associated with a giant cell astrocytoma of the pineal region. Diagnostic considerations are discussed.

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Alan R. Cohen, Jeffrey H. Wisoff, Jeffrey C. Allen and Fred Epstein

✓ The authors review their experience with the operative management of 19 consecutive cases of malignant astrocytoma of the spinal cord. There was a male to female ratio of 1.1:1, and the median age of the population was 14 years (range 1 to 32 years). The median duration of symptoms prior to definitive diagnosis was 7 weeks. Radical excision was carried out in all cases, with 18 patients (95%) receiving radiotherapy and 10 patients (53%) receiving chemotherapy as well.

To date, 15 (79%) of the 19 patients in this series have died, with a median survival period of 6 months following surgery. No patient improved after operation. Hydrocephalus was present in 11 patients (58%), seven of whom underwent ventricular shunting procedures. Dissemination of disease was found in 11 patients (58%). Extraneural metastases did not occur in the absence of a ventricular shunt. The authors conclude that malignant astrocytomas of the spinal cord are heralded by a short history followed by rapid neurological deterioration and usually death. The rationale for operation is discussed, and an aggressive approach utilizing adjuvant therapy directed at the entire neuraxis is suggested.

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Carl B. Heilman, Eddie S. Kwan, Richard P. Klucznik and Alan R. Cohen

✓ Cirsoid aneurysms of the scalp are notoriously difficult lesions to manage. The authors report a patient in whom a large traumatic cirsoid aneurysm of the scalp was eliminated using a combined neurosurgical and interventional neuroradiological approach. Transarterial embolization was utilized to reduce arterial blood supply to the fistula. Thrombogenic Gianturco spring coils were then introduced via direct percutaneous puncture of the aneurysm. The aneurysm thrombosed and the multiple tortuous scalp vessels disappeared. One month after embolization, a small area of skin necrosis over the aneurysm necessitated surgical excision of the lesion. The thrombosed aneurysm was easily resected with minimal blood loss. Percutaneous embolization with thrombogenic coils in this case was a safe and effective ablative technique.

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Alan R. Cohen, Dennis D. Pietronigro, Humberto Cravioto and Eugene S. Flamm

✓ In an attempt to improve glioma management, an animal model was developed to evaluate the therapeutic efficacy of intra-arterial 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Furthermore, the model was used to study the antitumor activity of D,L-alpha-difluoromethylornithine (DFMO), a polyamine-biosynthesis inhibitor, used both as a single agent and in combination with intra-arterial BCNU.

An N-methylnitrosourea-induced gliosarcoma (T9) was transplanted stereotaxically into the right caudate nucleus of male Fischer 344 rats. Animals receiving a single low-dose (5 mg/kg) intracarotid injection of BCNU 9 days following tumor implantation had a 57% increase in life span compared with untreated control rats (p < 0.001). Intracarotid drug delivery was more effective than systemic (intraperitoneal) administration of the same dose of BCNU.

When given as a single agent, DFMO demonstrated dose-dependent effectiveness. As part of a combined regimen, DFMO enhanced the antitumor therapeutic activity of both systemic (intraperitoneal) and intra-arterial BCNU. Survival times of animals receiving combined DFMO and intra-arterial BCNU were almost double those of untreated controls, and were significantly better than survival times of animals receiving combined DFMO and intraperitoneal BCNU. These findings suggest methods to optimize current clinical chemotherapy for glioma.