Anterior interhemispheric approach for clipping of subcallosal distal anterior cerebral artery aneurysms: case series and technical notes.

Distal anterior cerebral artery (DACA) aneurysms are rare, accounting for 1-9% of all intracranial aneurysms. Previous systematic reviews have highlighted that given the markedly increased incidence of major complications after endovascular treatment, microsurgical clipping is the more attractive treatment option with generally excellent clinical outcomes. Subcallosal DACA aneurysms constitute a rare subset of these aneurysms, requiring special anatomic considerations-particularly with regard to the approach. The aim of this study is to review the technical nuances of microsurgical treatment of subcallosal DACA aneurysms, including review of contemporary techniques through presentation of a microneurosurgical operative video. This is a retrospective case series and intraoperative microsurgical videos review. Three subcallosal DACA aneurysms were identified via retrospective query of our institutional neurosurgical database from December 2017 to May 2018. Two were female; median age was 74 years (range 70-83); all 3 underwent bifrontal craniotomy via bicoronal skin incision for aneurysm clipping. Aneurysms were located in left pericallosal-callosomarginal artery junction, bifurcation of azygos A2, and pericallosal artery related with azygos A2, and the anterior interhemispheric approach was used in all 3 operations. No acute stroke, hemorrhage, or major complications occurred, and all patients remained neurologically intact at the time of last follow-up (median 3 months, range 1-6). Although DACA aneurysms are rare, they represent an important variant for cerebrovascular neurosurgeons where microsurgical clipping can have better angiographic outcomes than endovascular treatment. Detail-oriented anterior interhemispheric arachnoid dissection through bifrontal craniotomy with its lower margin sitting at the superior orbital rim maximizes safe and effective clipping of subcallosal DACA aneurysms.