Minimally invasive presigmoid retrolabyrinthine suprameatal approach (PRSA): A cadaveric study for accessing premeatal anterior inferior cerebellar artery (AICA) aneurysms.

Background: The surgical management of aneurysms involving the proximal third of the anterior inferior cerebellar artery (AICA) usually necessitates complex and invasive approaches, thus posing major challenges. We aimed to investigate the infratentorial presigmoid retrolabyrinthine suprameatal approach (PRSA) as a surgical corridor for premeatal AICA aneurysms. Methods: We performed 10 PRSA dissections in five cadaveric heads. Twelve morphometric parameters were measured, analyzed, and categorized into pre-procedural, intra-procedural, and additional parameters. The typical anatomic-radiological characteristics and variations were evaluated, and the related anatomical and radiological parameters were analyzed to predict surgical accessibility. Results: Preoperative anatomic-radiological parameters provide valuable information to select patients with favorable anatomy that may offer appropriate surgical accessibility to the premeatal AICA through a PRSA corridor. The position of the basilar artery from the midline determines the degree of accessibility to the origin of AICA through the infratentorial PRSA. The PRSA for targeting proximal AICA aneurysms was also compared to other surgical approaches based on the available current literature. Conclusion: Premeatal AICA aneurysms can be accessed and clipped through the infratentorial PRSA corridor. This would allow surgeons to avoid the sacrifice of hearing and balance as compared to other available invasive alternative approaches. The selection of the appropriate patients should be based on the individualized preoperative radiological characteristics for both the vascular and bony anatomy.