The otoendoscope, with its wide-angle visualisation, has made it an increasingly popular tool to perform outer, middle and even inner ear surgery. Approaches to the IAC with the endoscope have been described by several authors. In this paper, Valente et al describe their systematic, step-by-step transcanal transpromontorial approach to the internal auditory canal in 10 cadaver temporal bones. The authors found that although it was easy to identify the tympanic segment of the facial nerve, the mastoid segment presented challenges. They suggest the chorda tympani nerve near the posterior wall of the medial third of the EAC as a landmark to identify the mastoid facial nerve. The authors recommend the transcanal transpromontorial approach for small intralabyrinthine schwannomas as all the important neurovascular structures can be visualised without a need to alter the middle ear or EAC anatomy with sparing of the IAC dura thereby preventing a CSF leak. The authors caution the reader that variations in jugular bulb and internal carotid artery anatomy can make this approach unsafe. For larger tumours, the authors recommend the translabyrinthine and transotic approaches as they work better compared to the endoscopic approach.
Endoscopic approach to the internal auditory canal (IAC)
Reviewed by Gauri Mankekar
The endoscopic transcanal approach to the internal auditory canal:
CONTRIBUTOR
Gauri Mankekar
Department of Otolaryngology-Head Neck Surgery, Louisiana State University Shreveport, Louisiana, USA.
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