2012 Volume 40 Issue 6 Pages 420-424
Of the complications associated with cerebral aneurysm clipping, injury to the perforating branches can greatly affect treatment outcome. Lenticulostriate artery injury is an issue in middle cerebral artery (MCA) aneurysms, occurring with particularly high frequency during surgery for MCA horizontal segment aneurysms. We retrospectively investigated the characteristics and treatment outcomes of MCA horizontal segment aneurysms and considered the therapeutic strategy.
The subjects were seven patients with MCA horizontal segment aneurysms from among 65 patients with MCA aneurysms in whom aneurysm neck clipping was performed between January 2008 and December 2011. The patients comprised one man and six women, with a mean age of 50.4 years (range, 37–65 years), with either ruptured (n=2) or unruptured (n=5) MCA horizontal segment aneurysms. Aneurysm morphologies included superior-wall (n=4) and inferior-wall (n=3) types, with a mean diameter of 4.5 mm. Multiple cerebral aneurysms were observed in six patients. The incidence of MCA horizontal segment aneurysms represented approximately 10% of the MCA aneurysms treated during the study period, which is comparable with previous study findings. All multiple aneurysm cases involved ipsilateral MCA aneurysms. No surgical complications, including perforating branch injury, were observed; both ruptured and unruptured cases scored 0 on the modified Rankin Scale.
During surgery, special attention must be given to preserving the perforating branches. Therefore, if we find that the aneurysm is embedded in surrounding parenchyma, it is freed and fully exposed, and the presence or absence of perforating branches behind the aneurysm is confirmed. We also do not advocate temporary occlusion of the parent artery. This wide surgical field and careful manipulation have helped achieve satisfactory surgical outcomes for MCA horizontal segment aneurysms. Previous studies also report comparatively favorable outcomes for unruptured aneurysms.
The increased surgical difficulty associated with ruptured MCA horizontal segment aneurysms compared to unruptured aneurysms suggests that surgery is indicated for MCA horizontal segment aneurysms even in the unruptured state.
