Mastering the Trans-Labrynthine Approach to Internal Acoustic Meatus: A Cadaveric Temporal Bone Study.

Abstract

The Trans-labrynthine approach, through Otic capsule gives direct approach to the cerebellopontine angle (CPA) and internal auditory meatus (IAM) with preservation of the facial nerve. Mastering the approach to IAM in a cadaver with anatomical landmarks is important to the budding Otologist & Neurotologist to approach the CPA with functional preservation of the Facial nerve in patients with Vestibular Schwannoma & other procedures. Transitioning surgical skills and anatomic knowledge from surgical anatomy textbooks and laboratory training to the operative room is challenging. 30 adult wet human cadaveric temporal bones were studied by performing Trans-labrynthine approach to the IAM by using ZEISS microscope in a temporal bone dissection lab. Photographs were taken by HD phone camera, imported into computer & labeled the anatomical landmarks. Wide exposure & 3D visualization of complex anatomical landmarks were noted in each step by step approach from basic to advanced procedure of Trans-labrynthine approach to IAM. The step by step approach to the IAM from basic to advanced procedure in a cadaveric temporal bone offers great orientation & opportunity to become a master of the complex surgical anatomy of IAM and in acquiring a 3D orientation of the critical structures.