Variability of the surgical anatomy of the neurovascular complex of the cerebellopontine angle.

The variability of the anatomic relationship of the anterior inferior cerebellar artery (AICA) to the facial (seventh) and vestibulocochlear (eighth) nerves was studied in 52 cerebellopontine angles (CPAs) from 26 adult cadavers. The AICA originated from the basilar artery (98.1%) or from the vertebral artery (1.9%) as a single (92.3% of CPAs) or duplicate (7.7%) artery. Each of the 52 CPAs had one or more arterial trunks that coursed in close proximity to the seventh and eighth cranial nerves and thus were said to be nerve-related. The nerve-related arterial trunks were divided into three segments based on their relationship to the nerves and meatus: the premeatal, meatal, and postmeatal segments. The nerve-related branches of the AICA gave rise to the internal auditory artery in 92.3% of the CPAs, the recurrent perforating artery in 78.8%, and the subarcuate artery in 30.8%. The importance of understanding the surgical anatomy of the neurovascular complex of the CPA when performing a vestibular neurectomy is reviewed.