Characteristics and Surgical Outcomes of Distal Anterior Cerebral Artery Aneurysms.

OBJECTIVE: Distal anterior cerebral artery (dACA) aneurysms are uncommon, and they require special treatment because of the narrow exposure in the interhemispheric fissures, the dense adhesions between the cingulate gyri and their association with multiple aneurysms or traumatic pseudoaneurysm. The aim of this study was to assess the characteristics and surgical outcomes of dACA aneurysms. METHODS: Among the 520 cases of cerebral aneurysms that were operated on from 1997 to April 2007, we experienced 31 cases of dACA aneurysms that developed in 30 patients. The medical records and radiological findings were retrospectively reviewed. RESULTS: The clinical characteristics of the patients with dACA aneurysms included the following. (1) The incidence of the dACA aneurysm was 5.9% of the total 520 cases, and the dACA aneurysms displayed a female predominance. (2) The most common location of the dACA aneurysms was the junction of the pericallosal and callosomarginal arteries. (3) Multiple aneurysms were found in 12 patients (40%), and the most concomitantly found aneurysm was MCA aneurysm. (4) The larger aneurysms more than 10 mm size all had thrombus in the sac, and their angiographic findings were underestimated compared with their findings on the operative fields. (5) dACA aneurysms shows frequent intracerebral hemorrhage (ICH) and subdural hemorrhage on the initial brain CT scan (28.5%). They also had a higher rate of intraoperative rupture (12.9%) than the rupture rate for the aneurysm at other locations (7.9%). (6) Traumatic pseudoaneurysms on the dACA were observed in two cases, and one of these cases showed massive ICH shortly after head trauma. (7) Twenty-six out of 30 patients (86.7%) showed a good outcome with a mortality rate of 3.3%. CONCLUSIONS: The dACA aneurysms are uncommon and they have unique characteristics compared to intracerebral aneurysms at other sites. Especially, a very careful surgical approach must be used for dACA aneurysms because they have a higher rate of intraoperative rupture. Yet the surgical outcome for dACA patients was good for the ruptured or unruptured aneurysm cases in our study. Therefore, dACA aneurysms have to be treated with considering their special characteristicsope