From external to internal auditory canal: surgical anatomy by an exclusive endoscopic approach

Surgical approaches to the inner ear and internal auditory canal (IAC) are well known and well documented. The objective of this study is to analyze the morphology, and surgical and anatomic findings of an exclusive endoscopic transcanal approach (EETA) to the IAC. Cadaveric dissections were performed on 11 temporal bones, approaching the internal auditory meatus directly through the external ear canal and avoiding mastoidectomy. In all cases, it was possible to dissect the internal carotid artery and jugular bulb with a 0° endoscope, and with good control of these two structures. The medial wall of the bony labyrinth guaranteed good landmarks for IAC dissection, such as the spherical recess, and the labyrinthine tract of the facial nerve. The IAC can be thoroughly visualized in the cadaver using EETA, avoiding mastoidectomy, extensive temporal bone tissue removal and external incisions. Clinically based reports will be required in future to strengthen our preliminary results.