The orphaned middle cerebral artery side-to-side in situ bypass as a favorable alternative approach for complex middle cerebral artery aneurysm treatment: a case series

Abstract Objective Middle cerebral artery (MCA) aneurysms are still primarily managed microsurgically. In cases of complex MCA aneurysms, revascularization may facilitate effective aneurysm treatment. The MCA candelabra provides excellent candidates for in situ side-to-side bypass. With this case series we describe applications of MCA in situ side-to-side bypass for the management of complex MCA aneurysms along with a review of the pertinent literature. Methods A retrospective review of a prospectively maintained neurosurgical patient database was performed to identify all patients treated with MCA side-to-side in situ bypass. Six consecutive patients were identified and included in the series, representing a single-surgeon experience between February 2016 and November 2018. Results Of the six complex MCA aneurysms, all were unruptured and half were treated via a mini pterional approach that also allowed for simultaneous anterior communicating artery aneurysm clipping in one case. Median (interquartile range) temporary occlusion time for anastomosis was 33 (30.3 - 35) minutes. Bypass patency was confirmed in all cases intra- and post-operatively. Median hospitalization time was 4.5 (2 – 8) days. Median follow-up was 5.5 (2.8 – 22.3) months. All patients achieved excellent or good (≤ 1) modified Rankin scale scores upon discharge and at follow-up. There were no mortalities and no technical, bypass-related, or ischemic morbidities. Conclusions Our experience with MCA side-to-side in situ bypass demonstrates its safety and utility in complex MCA aneurysm management. Favorable anatomy of the MCA branches allows for minimally invasive revascularization and clipping that potentially reduces hospitalization time and perioperative morbidity.