Cadaveric study of the endoscopic endonasal transtubercular approach to the anterior communicating artery complex

Abstract

The endoscopic transnasal approach to the anterior communicating artery (ACoA) complex is not widely performed. This cadaveric study investigated the surgical relevance of the anterior endoscopic approach to the treatment of ACoA aneurysms. Bi-nasal endoscopic transtubercular surgery was carried out on fresh adult cadavers. Primary outcomes measures incorporated dimensions of the endonasal corridor (operative field depth, lateral limits, size of the transplanum craniotomy and dural opening); vascular exposure (proximal and distal anterior cerebral arteries [ACA], ACoA, clinoidal internal carotid artery [ICA] segment); and operative manoeuvrability defined by clip placements (ipsilateral and contralateral). Eight cadaver heads were used (mean age 84±7years, range 76-94 years, 75% female). Mean operative depth was 97±4mm. The lateral corridors were limited proximally by the alar rim openings (31±2mm), and distally by the optic nerves (22±6mm). The endonasal craniotomy dimensions were 21±5mm anteroposteriorly, and 22±4mm laterally. Vascular exposure was achieved in 100% of subjects for the ACoA segment and the ACA segments proximal to the ACoA (A1). The ACA segments distal to the ACoA (A2) were accessible only in 40% of subjects. Endonasal clip placement across the ACoA segment, clinoidal ICA, A1 and A2 were 100%, 90%, 90%, and 30%, respectively. The ventral endoscopic endonasal approach to the ACoA complex provides excellent vascular visualisation without brain retraction or gyrus rectus resection. However, the limitation in access to the A2 for temporary clip placement may prove to be a significant limitation of this approach.

Keywords: Anterior cerebral artery; Anterior communicating artery aneurysm; Endoscopic endonasal approach.