Surgical anatomy of the labyrinthine artery - a systematic review and meta-analysis

The labyrinthine artery (LA) is usually exposed during surgical approaches to the cerebellopontine angle (CPA). However, the literature lacks a systematic review of its anatomy. Therefore, this study aimed to determine the LA's surgical anatomy, including its morphometry, branches, cranial nerve relationship, and origin. Major databases (PubMed, Embase, Science Direct, Scopus, and Web of Science) were searched systematically until March 2024. A total of 33 studies (n = 3778 arteries) were included. The most prevalent pattern of LA was a single branch, constituting 51% (95% CI: 9.9-56.7; p < 0.001) of the general population. Nevertheless, in the North American and Asian populations, there was a dominance of double branching with a prevalence of 51.3% (95% CI: 2.9-66.1; p < 0.001) and 50.4% (95% CI: 1.4-67.1; p < 0.001), respectively. Regarding the LA relationship with cranial nerves (CN), we found the vessel to be superior to the cochlear nerve in 90.5% (95% CI: 61.3-100.0; p = 0.001), inferior to the vestibular nerve in 89.4% (95% CI: 44.9-100.0; p < 0.001), and inferior to the facial nerve in 88.0% (95% CI: 64.0-100.0; p < 0.001). The most common vessel that the LA originated from was the anterior inferior cerebellar artery (AICA) - 75.4% (95% CI: 62.7-86.4; p < 0.001). However, this was not constant in all populations, as in Colombians, it arose from the BA most frequently at 66.5% (95% CI: 44.6-85.4; p = 0.025). Neurosurgeons must understand the surgical anatomy of the LA. It can provide important topographical information during tumor resection and aneurysm clipping, preventing many complications, including vertigo and hearing loss.