Surgical Treatment of Unruptured Intracranial Middle Cerebral Artery Aneurysms: Angiographic and Clinical Outcomes in 143 Aneurysms

OBJECTIVE: The purpose of this study was to determine the outcomes of surgical clipping in patients with unruptured middle cerebral artery (MCA) aneurysms. METHODS: A retrospective single-center database of 125 consecutive patients with 143 small MCA aneurysms (< 10 mm) who underwent surgical clipping was reviewed from January 2007 to December 2010. Clinical outcomes were assessed based on surgery-related complications and follow-up (mean: 17 months) using the modified Rankin scale (mRS). Angiographic outcomes were evaluated by conventional angiography (N = 96) or computed tomography angiography (N = 29) at postoperative weeks 1 and 6. RESULTS: There were no cases of mortality. There were three surgery-related complications (intracranial hemorrhage, meningitis and wound infection, respectively). The hemorrhagic event caused transient neurological deficits. All patients showed good clinical outcomes during follow-up (mRS 0-1). There was angiographic evidence of complete occlusion in 137 aneurysms (95.8%), a small residual neck in three aneurysms (2.2%) and partial for three aneurysms. In the three cases with partial clipping, the decision was made preoperatively to leave the residual sac to maintain distal flow, and muscular wrapping was performed. CONCLUSION: Our study demonstrates that surgical clipping of unruptured small MCA aneurysms yields favorable clinical and angiographic outcomes. Aneurysmal clipping can be safely recommended for patients with small unruptured MCA aneurysms.