Cavernomas comprise 8%–15% of intracranial vascular lesions, usually supratentorial in location and superficial. Cavernomas in the thalamus or subcortical white matter represent a unique challenge for surgeons in trying to identify and then use a safe corridor to access and resect the pathology. Previous authors have described specific open microsurgical corridors based on pathology location, often with technical difficulty and morbidity. This series presents 2 cavernomas that were resected using a minimally invasive approach that is less technically demanding and has a good safety profile. The authors report 2 cases of cavernoma: one in the thalamus and brainstem with multiple hemorrhages and the other in eloquent subcortical white matter. These lesions were resected through a transulcal parafascicular approach with a port-based minimally invasive technique. In this series there was complete resection with no neurological complications. The transulcal parafascicular minimally invasive approach relies on image interpretation and trajectory planning, intraoperative navigation, cortical cannulation and subcortical space access, high-quality optics, and resection as key elements to minimize exposure and retraction and maximize tissue preservation. The authors applied this technique to 2 patients with cavernomas in eloquent locations with excellent outcomes.
Robert A. Scranton, Steve H. Fung and Gavin W. Britz
Jeffrey T. Nelson and Nicholas C. Bambakidis
H. Richard Winn and Gavin W. Britz
David W. Newell, Gavin W. Britz and Jonathan Brisman
Case report and review of the literature
Gavin W. Britz, D. Kyle Kim and John D. Loeser
✓ Diffuse villous hyperplasia of the choroid plexus, which is distinct from bilateral choroid plexus papillomas, is extremely rare and is often associated with hydrocephalus due to the overproduction of cerebrospinal fluid (CSF). The authors describe an infant with hydrocephalus, diagnosed by computerized tomography scanning, who developed ascites following placement of a ventriculoperitoneal shunt and, subsequently, demonstrated excessive CSF production when the shunt was externalized. The patient was later successfully treated by placement of a ventriculoatrial shunt. Magnetic resonance imaging demonstrated diffuse villous hyperplasia of the choroid plexus as the cause of the patient's hydrocephalus. The literature on diffuse villous hyperplasia of the choroid plexus is reviewed.
Ali H. Mesiwala, Gill Sviri, Nasrin Fatemi, Gavin W. Britz and David W. Newell
The authors report the long-term results of a series of direct superficial temporal artery–middle cerebral artery (STA–MCA) bypass procedures in patients with moyamoya disease from the western US.
All patients with moyamoya disease treated at the University of Washington from 1990 through 2004 (39 patients) were included in this study. Patients underwent pre- and postoperative evaluation of cerebral perfusion dynamics. Surgical revascularization procedures were performed in all patients with impaired cerebral blood flow (CBF) findings.
The mean age of patients at diagnosis was 34 years (range 10–55 years). All 39 patients had impaired CBF and/or vasomotor reserve and underwent revascularization procedures: 26 patients underwent bilateral operations, 13 unilateral (65 total procedures). An STA–MCA bypass was technically possible in 56 procedures (86.2%); saphenous vein interposition grafts were required in 3 procedures (4.6%); encephaloduroarteriosynangiosis was performed in 6 procedures (9.2%). Three patients died due to postoperative complications, yielding a procedure-related mortality rate of 4.61%, and 8 experienced non–life threatening complications (for a procedure-related rate of 12.3%). Long-term follow-up appeared to indicate a reduction in further ischemic events in surviving patients compared with the natural history. Cerebral perfusion dynamics improved postoperatively in all 36 surviving patients.
Moyamoya disease may differ in the US and Asia, and STA–MCA bypass procedures may prevent future ischemic events in patients with this condition.
Gavin Britz and H. Richard Winn
Sabareesh Kumar Natarajan, Donald Born, Basavaraj Ghodke, Gavin W. Britz and Laligam N. Sekhar
The aim of this study was to analyze the histopathological changes in a consecutive series of 32 patients with brain arteriovenous malformations that were resected after undergoing endovascular embolization (22 using Onyx and 10 using N-butyl cyanoacrylate [NBCA]).
Selections from fixed paraffin-embedded specimens were stained for histological examination with H & E and Verhoeff-van Gieson stain. Lipid dye Oil Red O was used to stain vessel specimens that were embolized using NBCA. Specimens were evaluated for the presence of embolic agent, inflammation, angionecrosis, and evidence of recanalization. These results were correlated with the time interval between the bleeding, embolization, and resection.
The smallest vessel occluded by the embolic agent was 5 μm in the Onyx group and 20 μm in the NBCA group. There was evidence of vascular or perivascular inflammation in 20 (90.9%) of 22 and 9 (90%) of 10 specimens after Onyx and NBCA embolization, respectively. Chronic foreign-body giant cells were observed in 12 (54.5%) of 22 specimens after Onyx embolization, but were absent in specimens after NBCA embolization. Angionecrosis of the embolized vessel was observed in 13 (59.1%) of 22 specimens and in 4 (40%) of 10 specimens after Onyx and NBCA embolization, respectively. There was evidence of recanalization in Onyx embolized vessels in 4 (18.2%) of 22 specimens, and there was no evidence of recanalization after NBCA embolization.
Onyx penetrates much smaller vessels than NBCA. Inflammation occurs with both embolic agents at equal frequency. Evidence of chronic foreign-body giant cells and recanalization after Onyx embolization shows a long-standing reaction to Onyx and raises questions about the permanence of occlusion after Onyx embolization.
H. Richard Winn, John A. Jane, James Taylor, Donald Kaiser and Gavin W. Britz
Object. The prevalence of unruptured cerebral aneurysms is unknown, but is estimated to be as high as 5%. The goal of this study was to determine the prevalence of asymptomatic incidental aneurysms.
Methods. The authors studied all cerebral arteriography reports produced at a single institution, the University of Virginia, between April 1969 and January 1980. A review of 3684 arteriograms demonstrated 24 cases of asymptomatic aneurysms, yielding a prevalence rate of 0.65%. The majority (67%) of the 24 patients harboring unruptured aneurysms were women. More than 90% of the unruptured aneurysms were located in the anterior circulation and in locations similar to those found in patients with ruptured aneurysms. Nearly 80% of the aneurysms were smaller than 1 cm in their greatest diameter. The frequency of asymmetrical unruptured aneurysms (0.6–1.5%) was constant throughout all relevant age ranges (35–84 years).
Conclusions. While keeping in mind appropriate caveats in extrapolating from these data, the prevalence rate of asymptomatic unruptured aneurysms found in the present study allows an estimation of the yearly rate of rupture of these lesions. The authors suggest that this yearly rate of rupture falls within the range of 1 to 2%.