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Brian A. Iuliano, Robert E. Anderson and Fredric B. Meyer

-micron sections were cut from each coronal block and stained with hematoxylin and eosin. The area of infarction on each brain slice was measured in a blinded fashion using a computer-assisted image analyzer. The total infarct volume was calculated by integrating the infarcted area of all eight brain slices (area of infarct in square millimeters × thickness of slice). Both the core of the infarct, which had pancellular necrosis, and the peripheral areas that had dense populations of neurons with shrunken eosinophilic nuclei were included in the infarct. The border between the

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Fredric B. Meyer and Jeffrey N. Bruce

This edition of the Video Supplement entitled “Microsurgery of the Third Ventricle, Pineal Region, and Tentorial Incisura” highlights approaches to accessing the third ventricle for surgical resection of a variety of pathologies. The third ventricle has critical neurovascular anatomy that must always be respected to prevent patient harm. Visualization of critical anatomy in three dimensions from a surgeon' line of sight is important when planning the optimum surgical approach. Some of the keys to safely operating in this region include thoughtful head positioning, limitation of brain retraction, and the use of trajectories which capitalize on CSF cisterns and fissures. Some of the videos included in this volume illustrate standard operations while others depict more unique and innovative approaches that take advantage of these surgical windows. We hope you enjoy the videos included in this supplement.

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Editorial

Gamma Knife surgery and brain metastases

Fredric B. Meyer

control in ~ 94% of patients. The survival was predictably poor, with a median of ~ 7 months, and as with most brain cancers, the patient's Karnofsky Performance Scale (KPS) score was most important in predicting outcome. It should be noted that the tumors were not large, with a mean volume of 4.3 cm 3 . As in most series of this nature, the article is weakened by its retrospective design, heterogeneous group of patients in terms of interventions (see Tables 1 and 2), tumor number and type, treatment, and follow-up. For example, 10 patients had undergone prior surgery

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Fredric B. Meyer, John Huston III and Stephen S. Riederer

. , unpublished data). Specifically, pulsatile changes in aneurysm diameter and volume were measured to determine if there were significant increases between systole and diastole. Clinical Material and Methods Sixteen aneurysms were studied in 15 patients, of which six had hemorrhaged prior to cine phase-contrast MR angiographic examinations. Following MR angiography, the six ruptured aneurysms underwent surgical repair. Six of the unruptured aneurysms also underwent surgical obliteration; these included a basilar caput lesion treated by balloon embolization. Cine

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Bert A. Coert, Robert E. Anderson and Fredric B. Meyer

dosing. The objective of this study was to examine rigorously the dose-dependent effects of two NOS inhibitors and two NO donors on cortical infarction volume in a model of temporary focal cerebral ischemia that simulates possible ischemia during neurovascular procedures. Materials and Methods Following review and approval of our protocol by our institutional Animal Care and Use Committee, 92 adult male Wistar rats were administered halothane in a mixture of oxygen and air through a face mask at 1.5% during the surgical procedure and 1% during the occlusion period

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Bernard A. Coert, Robert E. Anderson and Fredric B. Meyer

again placed in a state of anesthesia, induced by pentobarbital, and then intracardially perfused using a warm (37°C) 2% TTC solution. The animals' brains were quickly removed and immersed in the TTC solution for 15 minutes to enhance staining, after which the heads were placed in a 10% buffered formaldehyde solution for 5 days. Eleven serial coronal sections were cut from each brain at 1-mm intervals and photographed. Total cortical infarction volume was calculated by integrating the infarct areas of all 11 sections (area of infarction in square millimeters

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Fredric B. Meyer

Williams and colleagues 1 provide a nice analysis of the benefits and complications of Gamma Knife surgery for parasellar meningiomas in this month's Journal of Neurosurgery . One of the important components of their review in reference to the literature is the longer-term follow-up with a mean of 7 years. In their cohort of 138 patients with “parasellar” meningiomas, 84 had undergone prior surgery. The mean tumor volume was 7.5 ml (0.2–55 ml). They attempted to deliver a radiation dose of 12–15 Gy, decreasing to less than 8 Gy adjacent to the optic nerve

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Bruce E. Pollock and Fredric B. Meyer

, resulting in the following conclusions. First, AVM obliteration correlates with the radiation dose delivered to the margin of the malformation. 2, 8 Assuming that the radiation is well targeted, the chance of an AVM cure is approximately 70, 80, and 90% for radiation doses of 16, 18, and 20 Gy, respectively. Second, the likelihood of radiation-related complications occurring after AVM radiosurgery relates in some measure to the radiation dose directed to surrounding tissue (most commonly used is the 12-Gy volume) and the location of the AVM. 1 Patients harboring AVMs in

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Jamie J. Van Gompel, Todd B. Nippoldt, Dominique M. Higgins and Fredric B. Meyer

61 39 sex hormone 50 39 Magnetic Resonance Imaging and Hypothalamic Involvement Progressive hypothalamic involvement (as defined by Sainte-Rose Grade 0–2) correlated with postoperative weight gain ( Fig. 4 ; p = 0.04, Wilcoxon test); however, hypothalamic involvement did not correlate with preoperative BMI (p = 0.5). Left-sided hypothalamic compression correlated with postoperative weight gain (p = 0.006), but right-sided compression did not (p = 0.15). Furthermore, total volume of the tumor correlated with hypothalamic involvement ( Fig. 5

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Fredric B. Meyer, Robert E. Anderson, Tony L. Yaksh and Thoralf M. Sundt Jr.

infusion were covered in aluminum foil. Nimodipine was supplied at a concentration of 1 mg/5 ml of a solvent solution of polyethylene glycol. Aliquots of this solution were mixed in a corresponding volume of 0.9% NaCl to give a final volume of 20 cc at a pH of 5.55 to be infused over 4 hours at 0.5 µ g/kg/min. Statistical Analysis For each hourly measurement, results at the severely ischemic sites in the 10 control animals were compared with the results at the severely ischemic sites in the 10 animals treated with nimodipine. Likewise, results at the moderately