3.2 Disease characteristics 
Nineteen (12.1%) of the whole cohort were noted to have stapes erosion, 11 of these patients were dealt with TEES (22% of the TEES) compared to only 8 (7.5%) in the microscopic group (P<0.001). Other disease characteristics such as tympanic membrane perforation, condition of ossicles, site, and extent of cholesteatoma are shown in Table 1.