✓ A variety of agents have been used to coat aneurysms as an alternative to clipping. These agents were employed more frequently prior to the routine use of the operating microscope and the presently available variety of aneurysm clips. One such coating agent is methyl methacrylate. This report describes a patient with an anterior communicating aneurysm that rebled 20 years after being encased in methyl methacrylate. At operation, the pulsating aneurysm had eroded the adjacent layer of methyl methacrylate, creating a small intervening space. This space allowed removal under the microscope (with a high-speed air drill and a diamond bit) of the methyl methacrylate from the anterior cerebral arteries and aneurysm, exposing it for definitive clip placement. The feasibility of clipping encased aneurysms is discussed.
Christopher S. Ogilvy and Charles E. Poletti
Christopher S. Ogilvy and Robert G. Ojemann
✓ A safe technique is described for performing a lateral posterior fossa craniotomy to gain access to the cerebellopontine angle. The method makes use of currently available high-speed air drills. Thus, it is possible to replace the removed bone at the conclusion of the procedure and to re-establish normal tissue planes while providing rigid protection to the posterior fossa.
Kenneth I. Maynard and Christopher S. Ogilvy
✓ Using standard immunohistochemical techniques and an improved procedure for whole-mount vascular preparations, the authors describe the pattern and density of innervation of calcitonin gene—related peptide (CGRP)-like, neuropeptide Y (NPY)-like and vasoactive intestinal polypeptide (VIP)-like immunoreactivity in major arteries of postmortem adult human circles of Willis. Calcitonin gene—related peptide-, NPY-, and VIP-LI exhibited a variety of varicose and nonvaricose single axons, and small and large perivascular nerve bundles. Although the density of innervation within each vascular segment was highly variable, the pattern of innervation for each neuropeptide observed was consistent throughout the circle of Willis. With the use of human and rat circles of Willis as positive control preparations, the lack of CGRP-LI, NPY-LI, and VIP-LI in vessel segments taken from five cases of intracranial arteriovenous malformations (AVMs) is also reported. It is concluded that adult human circles of Willis exhibit CGRP-LI, NPY-LI, and VIP-LI perivascular nerves. In addition, intracranial AVMs do not possess these peptide-containing nerves that, in animals, normally mediate neurogenic control in the cerebrovasculature. It is hypothesized that this lack of innervation, and hence neurotrophic influence, may contribute to the development of AVMs.
Fred G. Barker II and Christopher S. Ogilvy
✓ The authors report findings from a metaanalysis of all published randomized trials of prophylactic nimodipine used in patients who have experienced subarachnoid hemorrhage (SAH). Seven trials were included with a total of 1202 patients suitable for evaluation. Eight outcome measures were examined, including good versus other outcome, good or fair outcome versus other outcome, overall mortality, deficit and/or death attributed to vasospasm, infarction rate as judged by computerized tomography (CT), and deficit and/or death from rebleeding.
Nimodipine improved outcome according to all measures examined. The odds of good and of good plus fair outcomes were improved by ratios of 1.86:1 and 1.67:1, respectively, for nimodipine versus control (p < 0.005 for both measures). The odds of deficit and/or mortality attributed to vasospasm and CT-assessed infarction rate were reduced by ratios of 0.46:1 to 0.58:1 in the nimodipine group (p < 0.008 for all measures). Overall mortality was slightly reduced in the nimodipine group, but the trend was not statistically significant. The rebleeding rate was not increased by nimodipine. A metaregression yielded findings indicating that the treatment effect of nimodipine in individual trials was positively correlated with the severity of SAH in enrolled patients.
Although the majority of individual trials examined did not have statistically significant results at the p < 0.01 level according to most outcome measures, the metaanalyses confirmed the significant efficacy of prophylactic nimodipine in improving outcome after SAH under the conditions used in these trials.
Aneurysmal subarachnoid hemorrhage in a patient with bilateral A1 fenestrations associated with an azygos anterior cerebral artery
Case report and literature review
Robert M. Friedlander and Christopher S. Ogilvy
✓ Fenestration of the proximal anterior cerebral artery (A1 segment) is a rare occurrence. This vascular anomaly is often associated with aneurysms and other abnormalities. The current article describes the case of a 33-year-old man who presented with a subarachnoid hemorrhage secondary to a ruptured aneurysm originating from the proximal end of an A1 fenestration. This patient also had a contralateral A1 fenestration as well as an azygos anterior cerebral artery. This is the first report of such an unusual vascular anatomy. The literature is reviewed and possible embryological mechanisms are discussed.
Bob S. Carter, Jonathan L. Brisman and Christopher S. Ogilvy
Carlos E. Sanchez, Christopher S. Ogilvy and Bob S. Carter
✓Successfully measuring cerebrovascular neurosurgery outcomes requires an appreciation of the current state-of-the-art epidemiological instruments, their specific relevance to surgical treatments and the underlying pathological entity, and ultimately the right set of questions for the next generation of studies. In this paper the authors address these questions with specific attention to measurement targets, individual modeling scales, and types of studies, all within a conceptual framework for specific disease models in their current state of outcomes modeling in cerebrovascular neurosurgery.
Patrick J. Codd, Alim P. Mitha and Christopher S. Ogilvy
Arteriovenous malformations are generally considered to be cured following angiographically proven complete resection. However, rare instances of AVM recurrence despite negative findings on postoperative angiography have been reported in both children and adults. In this paper, the authors present the case of a 33-year-old woman with 2 AVM recurrences. This patient represents the oldest case of recurrent AVM, and the first adult double recurrence reported in the literature. The case is presented, the radiological and surgical features are considered, and the literature on recurrent AVMs is reviewed.
Andrea L. Halliday, Christopher S. Ogilvy and Robert M. Crowell
✓ True intracranial arteriovenous fistulas are rare. The authors report a case of a direct fistula between the intracranial portion of the vertebral artery and the lateral medullary venous system. The patient initially presented with a subarachnoid hemorrhage. An open surgical approach with clip obliteration of the lesion was used. The anatomy of this lesion and its surgical management are described.
Khalid M. Abbed and Christopher S. Ogilvy
Patients who present with an intraparenchymal hematoma associated with a ruptured aneurysm usually require urgent clot evacuation and aneurysm obliteration. The impact of the presence of hematoma on outcome has been poorly characterized. The authors report on 460 patients who had dense subarachnoid hemorrhage (SAH) (Fisher Grades 3 and 4) with and without associated hematoma.
Of the 959 consecutive patients who presented with SAH, 460 patients with Fisher Grade 3 and 4 SAH were analyzed and divided into two groups: those with (Group 1) and those without (Group 2) hematoma. The presenting Hunt and Hess grade and 6-month outcomes of the two groups were compared.
Of the 460 patients, 116 (25%) had intraparenchymal hematomas and admission Hunt and Hess grades were worse in Group 1 compared with Group 2. Outcome scores were worse for Group 1 compared with Group 2; however, when comparing Group 1 and Group 2 within the same initial Hunt and Hess score, there was no statistical difference in outcome.
Intraparenchymal hematoma in association with SAH does not differ significantly from those patients without associated hematomas. We therefore recommend aggressive clot evacuation and aneurysm obliteration.