The Prevalence of Labyrinthine Fistula in Chronic Otitis Media Surgery in Shiraz, Southern Iran

Background: The incidence of fistulas found during the surgery for chronic otitis media with cholesteatoma has been reported in a wide range in different geographical areas. This study aims to find the prevalence of labyrinthine fistula in the south of Iran. Methods: A prospective cross sectional study of 787 (504 ears belong to 462 patients) consecutive tympanoplasty with or without mastoidectomy for chronic otitis media was performed. Data on preoperative clinical and preoperative and postoperative hearing status and intraoperative findings were analyzed. Results: A labyrinthine fistula was found at surgery in 24 (4.7%) ears of the total 504 ears belonging to 462 patients undergoing surgery for chronic otitis media. Location of the fistula was the lateral semicircular canal in 23, posterior semicircular canal in 1 and promontory in 1 subject. There was a statistically significant difference in preoperative and postoperative AC threshold in 500-3000 Hz frequency and ABG 500-3000 Hz, but there was no statistically significant difference in the other variables. Conclusion: Regarding postoperative hearing outcome in the labyrinthine fistula surgery, it seems that there is no universal method of reporting of hearing results. Past hearing evaluation methods in the literature have been often poorly comparable, based on different methodology.