Bilobulated aneurysms at the origin of the posterior communicating artery

The purpose of this paper is to describe the occurrence of bilobulated aneurysms at the origin of the posterior communicating artery.

Bilobulated aneurysms at the origin of the posterior communicating artery from the internal carotid artery are rarely reported in the literature. A review of the literature showed only one report in which this type of aneurysm was addressed.

A consecutive series of 85 aneurysms operated by a single surgeon in 75 patients during an eight-year period (March 1995-February 2003) at the University Hospital was reviewed retrospectively. The incidence, radiological findings, intraoperative findings, surgical treatment and outcome of patients with bilobulated aneurysms at the origin of the posterior communicating artery were analyzed. The pathophysiologic mechanism for the formation of the bilobulated aneurysm was analyzed for each case.

Thirty-two aneurysms (37.6%) located at the origin of the posterior communicating artery were operated. Four patients who had angiographic evidence of a bilobulated aneurysm at the origin of the posterior communicating artery were identified and operated. Among those four patients, only three had a bilobulated aneurysm. In one patient, microsurgical exploration revealed the presence of two consecutive aneurysms originating from the posterior communicating artery. The incidence of bilobulated aneurysms at the origin of the posterior communicating artery was 9.4%. One patient died during the postoperative period for a 25% mortality rate.

The incidence of this type of aneurysm is low; therefore, they represent a technical challenge to the neurosurgeon.