The Role of Endoscopic Stapes Surgery in Difficult Oval Window Niche Anatomy

By June 7, 2019

Fernandez, Ignacio Javier1; Bonali, Marco1; Fermi, Matteo1; Ghirelli, Michael1; Villari, Domenico1; Presutti, Livio1
1 Department of Otolaryngology Head and Neck Surgery, University of Modena, Modena, Italy.

Stapes surgery can be challenging in case of anatomical variations of the oval window niche (OWN) area, as in very narrow OWN or in an overhanging facial nerve. The aim of the study was to explore the role of endoscopic stapes surgery in cases with difficult OWN anatomy.

– Study design: Retrospective case series analysis
– Setting: tertiary referral center
– Patients:  Among patients undergoing endoscopic stapes surgery between 2008 and 2017, those fulfilling the CT scan criteria for “difficult” OWN, according to the measurements (width, depth and facial-promontory angle) and cut-off values defined in the literature were included in the study.
– Interventions: The intraoperative endoscopic exposure of anatomical structures of the OWN and surgical difficulties were analysed through the review of the operative videos. Furthermore, we analyzed the association between endoscopic visualization of anatomical details and the radiological measurements.

Main outcomes: Eighteen out of 205 patients (8,7%) were included. The 94.4% of patients obtained an optimal endoscopic exposure and visualization of all the anatomical details considered in the study, during each step of stapes surgery.

The OWN measurements did not affect significantly the endoscopic exposure of the footplate or any of the other anatomical details.

The anatomic features of the oval window area which reduce the visualization in microscopic surgery, did not affect the surgical exposure in endoscopic stapes surgery. Patients having a difficult anatomy of the OWN can be treated safely with the endoscopic approach. In the case of a predicted “difficult anatomy”, the endoscopic approach can be considered a viable option.