Surgical exclusion of unruptured middle cerebral artery aneurysms: experience of 126 cases.

A group of 126 surgical patients with 143 unruptured MCA aneurysms was evaluated in order to determine the risks of treatment and possible adjuncts for safer surgery. The precise location and size of the aneurysms were determined in each case; 21 aneurysms were located on the M1 tract, 109 on the main division - which consisted of more than two branches in 10 cases and was proximally located in 12 cases - and 13 were distal; 36 aneurysms were small (<7 mm), 90 standard, and 17 large or giant (>15 mm); 45 patients harbored multiple aneurysms (12 on the ipsilateral MCA). The aneurysms were excluded by clip in most cases, with the assistance of intraoperative flowmetry in 78 patients. Temporary proximal vessel occlusion was used in 57 patients (>10 min in 8 cases), without significant effects on radiological or clinical outcome. After surgery, newly occurring minor deficits were observed in 5 patients and significant deficits in 4; one patient died from an intractable coagulopathy. The low rate (3.9 %) of unfavorable results (modified Rankin Score > 2) linked to surgery justifies serious consideration for treatment in these patients, especially when facing the high disability rate after the rupture of aneurysms in this anatomical location.