Transsphenoidal surgery utilizing computer-assisted stereotactic guidance.

Computer-assisted guidance technology represents the next step in the application of stereotactic techniques to skull base surgery. Use of this 3-D technique reduces operative time and complications as the technique allows a more direct approach with precise real-time anatomical guidance. We present seven cases of transsphenoidal parasellar surgery where this technique has been employed. The pathology included lesions of the sella turcica, parasellar region and the petrous apex.

Endoscopic/Microscopic approach to sphenopetroclival complex: an anatomical study.

A dilemma presents itself to the otoneurologist and neurosurgeon when determining the least invasive surgical approach to giant cholesterol cysts (GCC) of the petrous apex of the temporal bone. These lesions can be diagnosed with a fair degree of certainty with imaging studies. Transmastoid and subcochlear approaches may be inadequate to access these lesions, and the transcochlear approach results in the sacrifice of hearing. A minimally invasive, combined microscopic and endoscopic sublabial transsphenoid approach to drain and marsupalize these lesions has been chosen by the authors in those cases that are anatomically possible. The purpose of this article is to establish the feasibility of exenterating anterior petrous apex cells by way of this approach, and to better conceptualize the anatomy of the Spheno-Petro-Clival Complex (SPC). Ten Fresh cadaveric "whole head" specimens were dissected with, endoscopic/microscopic control, through midline, sublabial, transseptal, and transsphenoidal routes to the petrous apex. The three-dimensional relationships of the sphenoid sinus, petrous apex, and the clivus were further demonstrated by dissections of the same specimens from the posterior fossa. Sagittal cut sections were also performed. After confirming the feasibility of this approach by dissections, the technique was adopted for performing drainage of GCC of the petrous apex in clinical cases.

delta-Aminolevulinic acid effects on neuronal and glial tumor cell lines.

Acute intermittent porphyria (AIP) or precursor syndrome is a well described neuropathic clinical entity with incompletely known etiology. The most prominent biological abnormalities associated with this syndrome are elevations in serum and hepatic delta-aminolevulinic acid (ALA) and porphobilinogen (PBG). We determined the impact of ALA and PBG on human neuroblastoma and glioblastoma tumor cell survival as measured by the MTT assay. ALA proved to be cytotoxic in neuroblastoma cells, while PBG lacked cytotoxic effects. This cytotoxic effect of ALA could be enhanced by deferoxamine and diminished by heme, presumably through modulation of ALA synthesis. In conclusion, ALA excess may prove to be associated with the development of neuropathy in AIP.

A saturation threshold for taxol cytotoxicity in human glial and neuroblastoma cells.

The cytotoxic effects of taxol at concentrations of 0.001-1.0 microgram/ml were determined in two human glioblastoma multiforme, two neuroblastoma and two primitive neuroectodermal tumor cell lines. The neuroectodermal cell lines were established from previously treated patients, while the glioblastomas were from untreated patients. At exposure durations of 1, 4 and 24 h there was an inverse taxol concentration-survival relationship for all six cell lines as measured by the MTT method. Significant differences in sensitivity to taxol among these cell lines were observed; the most resistant cell line SK-N-FI is characterized by very high levels of MDR1 expression and the most sensitive SK-N-AS by very low levels. An additional level of complexity concerns a saturation threshold for taxol-induced cytotoxic effects which when reached precludes additional effects of prolonged or additional exposure. Tumors of the brain and peripheral nervous system appear to be sensitive to taxol. However, dosage necessary to maximize cytocidal effects in tumors requires knowledge of at least the range of each tumors constitutive sensitivity to taxol and a way to optimize drug delivery.

Combined approach for excision of cervical nerve tumors with dural extension.

Tumors of the cervical plexus are rare. Often these tumors are found on routine exam as asymptomatic masses. We present our experience in managing four patients with tumors with dural extension. Three of these lesions were neurilemomas and one was a meningioma. Symptoms and signs included weakness and hypoesthesia. Evaluation included complete neurologic examination with electromyography (EMG). Magnetic resonance imaging (MRI) was the best diagnostic tool to see tumor extent into the epidural and intradural space. Computed tomography (CT) or plain x-rays were used to evaluate the degree of destruction of the cervical spine. The surgical removal of these tumors was performed by a two-team approach. A posterior laminectomy was combined with an anterior neck exploration. Follow-up shows persistent upper extremity weakness in two patients, hypesthesia in three patients, and anesthesia of the anterior chest wall in two patients. Patients with these lesions should be informed of the potential neurologic consequences of removal.

Collegiality: what is it?

The privileges of members of the academic medical collegium consist of the following: freedom to pursue medical knowledge, performance of therapeutic interventions, opportunity to instruct, freedom to engage in experimentation, and to share in the expression and communication of medical knowledge with colleagues. The obligations are the same as those of the purely academic collegium mentioned above. Additionally, there are the obligations specific to the medical collegium: the care and cure of the sick, fulfillment of the moral covenant to the patient, to guarantee the life cycle of medical ideas, to assure academic critique in medicine, the stewardship of medical knowledge, and adherence to a professional code. We feel that the relationship among medical colleagues adheres to a codified set of duties, one that can be objectively relied upon to protect the endangered species of American academic medicine, the collegial environment.

Metabolism of the malignant astrocytoma.

A comprehensive review of the biochemical organization of the malignant astrocytoma is presented. The review is intended for neurosurgeons. It outlines the metabolic flow of events beginning with energy and substrate utilization, followed by structural components (protein, lipids, etc.) and tumor cell secretory products, and ending with nucleic acid synthesis. Cellular pH, tumor-induced cerebral edema, tumor blood flow, and tumor necrosis are also considered.

Epidural spinal infection in intravenous drug abusers.

The incidence of spinal epidural abscess and disk space infection appears to be rising in intravenous drug-using patients. We report 18 cases seen over three years in two municipal hospitals. Staphylococcus aureus was the most common infective agent, but two patients had Mycobacterium tuberculosis infection. Computed tomography of the spine facilitates diagnosis. Early treatment improves outcome but host factors play a role in recovery.

Third ventricular primary cerebral neuroblastoma. Electron-microscopic and immunohistochemical study.

A case of third ventricular primary cerebral neuroblastoma with secondary hydrocephalus is reported. Light microscopy showed a cell pattern that resembled either ependymoma or oligodendroglioma. The tumor was confirmed to be neuroblastoma by electron microscopy and immunohistochemistry. Immunoperoxidase staining was positive for neuron-specific enolase and negative for glial fibrillary acidic protein.

Transoral removal of missile fragments from the C1-C2 area: report of four cases.

Low velocity firearm damage to the upper cervical spine without neurological deficit occurs infrequently. Four cases of gunshot fragments involving the anterior elements of C1 and C2 are presented. In all four cases, the fragments were removed via a transoral approach without neurological complications or mechanical instability.

Brainstem haematomas: review of the literature and presentation of five new cases.

Fifty-one cases of brainstem haematoma that have undergone neurosurgical intervention since Finkelnburg's first exploration in 1905, are presented, together with five new cases. The location, incidence, aetiological and pathological factors, as well as clinical syndromes are reviewed. Diagnostic criteria are presented. The distinction between brainstem "haematoma" and "haemorrhage" is stressed. A retrospective comparison of 56 surgically treated cases and 31 conservatively managed cases is made, as is an analysis of the natural history of the disease process. Based on currently available data, the conclusion is drawn that patients with brainstem haematomas fare quite well after surgical therapy.

Cocaine-related intracranial hemorrhage. Report of nine cases and review.

Nine cases of intracranial hemorrhages related to cocaine usage are presented. Another 5 cases from the literature are reviewed. The relationship between severe cocaine-induced hypertension, and the development of subarachnoid or intracerebral hemorrhages is noted, and apparently is related to sudden transient increases of blood pressure related to cocaine use.

Traumatic intraspinal pneumocele.

Traumatic intraspinal pneumocele (TIP) is a radiologic finding in which air is visualized within the spinal canal on routine cervical spine x-rays following a head injury. TIP may be the initial radiologic evidence of a severe central nervous system injury. The presence of TIP will alert a physician to the severity of the head injury, as well as the need for further radiologic investigations.

Hemangiopericytoma of the pituitary fossa: case report.

A case of hemangiopericytoma presenting as a sellar and suprasellar mass is reported. Although this is the first report of this tumor in such a location, it appears similar to hemangiopericytomas found in other locations.