Distal anterior cerebral artery aneurysms.

BACKGROUND

The incidence of saccular aneurysms in the distal anterior cerebral artery (DACA aneurysms), also called pericallosal or A2 aneurysms, has been estimated to be from 1.5 to 9.0% of all intracranial aneurysms in large series in the literature [5,10,12,18]. All reported series of DACA aneurysms have shown a high association with intracranial aneurysms in other locations. These aneurysms are fragile, frequently rupture prematurely during exposure, and have a higher morbidity than expected from their angiographic appearance and location.

METHODS

A total of 1,350 patients with cerebral aneurysms were operated in the Department of Neurosurgery at Santa Casa Hospital in Belo Horizonte from January 1982 to January 1998. Seventy-two of those 1,350 patients had DACA aneurysms (5.3%), 51 female and 21 male. The age ranged from 26 to 69 years, the mean age being 44 years. This group of patients is reported herein. We propose three different approaches to DACA aneurysms depending on their location, all of them performed through a unilateral triangular bone flap that can then vary from fronto-basal to parietal.

RESULTS

There was no mortality among patients with a single DACA aneurysm. Five deaths in this series were cases of multiple aneurysms. In patients with preoperative Hunt and Kosnick grades I and II [9], we had 90% good results. In grade III patients, we achieved 68.4% good results. The only grade IV patient had a full recovery. All 74 DACA aneurysms in the 72 operated patients were completely clipped, including two giant aneurysms.

CONCLUSION

DACA aneurysms have higher morbidity and mortality rates when compared to other supratentorial aneurysms. We recommend the use of a unilateral interhemispheric approach as the most appropriate for aneurysms in this location. In cases of patients with multiple aneurysms who require two different craniotomies, we propose two surgical stages, starting with the aneurysm that has bled. A high mortality rate was noted when two craniotomies were performed in the same sitting.