Analysis of the Surgical Efficacy and Risk Factors of a One-stage Unilateral Approach for Clipping Bilateral MCA Mirror Aneurysms.

[BACKGROUND] Numerous microsurgical approaches are available for treating middle cerebral artery (MCA) mirror aneurysms. However, a definitive conclusion regarding which approach yields the best outcome has yet to be reached.

[METHODS] Thirty-three patients with MCA aneurysms were categorized into 2 groups: one-stage unilateral approach and other surgical approaches. Prognostic differences were compared using the Modified Rankin Scale (mRS). In addition, the length of hospital stay and costs were also compared. Among the patients with a proposed preoperative one-stage unilateral approach, they were divided into success and failure groups, and these factors were collected, including Hunt-Hess grade, contralateral aneurysm orientation and maximum diameter, contralateral A1+M1 length, and contralateral ICA bifurcation angle. These parameters were analyzed using multivariate logistic regressions to identify the risk factors.

[RESULTS] The prognosis of patients in the one-stage unilateral approach group did not differ significantly from that of other surgical approaches. However, patients in the one-stage unilateral approach group experienced shorter hospital stays and incurred lower hospital expenses. In the multivariate regressions, the length of the contralateral A1+M1 was identified as an independent risk factor.

[CONCLUSIONS] The one-stage unilateral pterional approach for clipping bilateral aneurysms is an effective method of treating MCA mirror aneurysms. However, in cases where patients have an excessive length of A1+M1 on the contralateral side, this approach may result in surgical failure.