Underwater endoscopic ear surgery for repair of lateral semicircular canal fistulae secondary to cholesteatoma—a pilot safety analysis

Background: Underwater endoscopic repair of labyrinthine fistulae has the potential to improve visualisation and reduce the exposure of the membranous labyrinthine to air when removing disease. This work sought to undertake a safety and efficacy analysis of a novel method of underwater endoscopic ear surgery (UWEES), which can be used to repair cholesteatomatous labyrinthine fistulae. Methods: A retrospective review was conducted of 11 patients with high grade (Dornhoffer IIa or greater) labyrinthine fistula secondary to cholesteatoma operated on between 2015–2022. All patients had UWEES technique, resurfacing repair of fistulae using combinations of temporalis fascia, bone pate and/or composite cartilage. The primary outcome was pre- and post-operative bone conduction audiograms conducted at a mean of 18 months postoperatively [standard deviation (SD) 22] and secondary outcomes included subjective vertigo and recidivistic disease. Results: There was no significant difference in mean bone conduction thresholds pre- and post-operatively (Z=−0.664, P=0.51). Ten out of the eleven patients had a type II fistula (5 type IIa, 5 type IIb) and one had type III. There was no significant difference in mean hearing outcome between Dornhoffer type 2a and 2b fistulas. The patient with type 3 fistula had significant deterioration in hearing post-operatively. Only 1 patient (out of 9 patients with preoperative vertigo) had residual vertigo after 6 months. One patient (9%) had recurrent disease and one patient (9%) had residual disease at a mean follow up time of 34 months (SD 22). Conclusion: UWEES may be an effective method to preserve hearing. Longer follow up is required to assess recidivistic outcomes and full safety of the technique.