M2/M2 side-to-side rescue anastomosis for accidental M2 trunk occlusion during middle cerebral artery aneurysm clipping: Technical note

Objective: A technically feasible and rapid technique for revascularizing t he main branches of the middle cerebral artery (MCA) is described. This tec hnique is applied mainly when clipping of an MCA aneurysm is complicated an d occlusion of the origin of an MCA main branch results. Methods: M2/M2 side-to-side anastomosis was applied in two patients in whom unplanned M2 occlusion occurred during the course of complicated MCA aneur ysm clipping. The first patient underwent an emergency procedure after temp oroparietal intracerebral hemorrhage. Unilateral mydriasis precluded preope rative angiographic workup, and a complex large MCA aneurysm was found as t he source of hemorrhage. Shaping of the aneurysm neck by bipolar coagulatio n and clipping resulted in accidental occlusion of the superior trunk, and patency could not be regained despite multiple clip corrections. The second patient had an unruptured multilobulated aneurysm 8 mm in maximum diameter . Continuity of the inferior trunk was lost during clipping because of a te ar at the origin. In both instances, side-to-side anastomosis was placed ap proximately 15 mm from the bifurcation, where the MCA main trunks ran side by side for a length of approximately 5 mm. Results: After intracerebral hemorrhage, the first patient recovered to a l evel of moderate disability within 2 months. Substantial hemiparesis and ex pressive dysphasia remained as sequelae of the intracerebral hemorrhage. Di gital subtraction angiography 2 months after the emergency procedure confir med patency of the side-to-side anastomosis. The second patient was neurolo gically intact after recovery from anesthesia. Before discharge from the ho spital on postoperative Day 8, digital subtraction angiography confirmed pa tency of the anastomosis. Conclusion: The MCA main branches usually run in close proximity for a shor t segment at the bottleneck entrance to the insular cistern. M2/M2 side-to- side anastomosis at this site is a rapid and feasible mode of revasculariza tion of an M2 trunk accidentally occluded during complicated MCA aneurysm c lipping.