2.1 Reporting guideline
A phenomenon of extensive ossification over the lateral semicircular canal was found in clinic. Due to the difficulty in intraoperative identification, iatrogenic injury was easy to occur. This phenomenon is not common in clinical practice by literature review. All surgical cases (156 cases) of chronic otitis media and cholesteatoma in the past 3 years were further reviewed and 7 of them were found. The clinical characteristics of these 7 cases were reviewed in order to provide clinical experience for preoperative recognition and intraoperative management.