Contralateral Approach to the Trigone of the Lateral Ventricle

Abstract

The lateral ventricle is the preferred location (80%) of intraventricular meningiomas, which in turn constitute 1.0%e1.7% of all intracranial meningiomas (1). The trigone is by far the commonest site of these lateral ventricular tumors. One has to grapple with various aspects when planning surgery of meningiomas in the trigone: the large size of tumor before detection, the vascular supply of the tumor, and the critical structures around the trigone. Meningiomas of the lateral ventricle usually attain a large size before becoming symptomatic because of the slow progress of the lesion in a cavity-providing space. A large tumor in the deep location makes for prolonged operating time and piecemeal decompression before excising the capsule. This sometimes results in significant blood loss in highly vascular tumors before one can occlude the vascular supply from both the anterior and posterior choroidal arteries, especially from the lateral posteriorchoroidalartery.Wehavefoundendoscopeassistanceauseful adjunct in visualizing, coagulating, and interrupting the vascular supply before undue blood loss from significant decompression. One of the major concerns in approaching the trigone is the risk to opticradiation when utilizing anyapproachthroughthelateral wall. Hencealternateapproaches—posteriortranscallosalandposterior interhemispheric parieto-occipital—have been proposed. However, there are concerns of disconnection syndrome associated with the posterior callosal approach and a narrow trajectory and uncomfortableangleofentryintheposterior interhemispheric approach. The other problem of both these approaches is the