The relationship between individual ossicular status and conductive hearing loss in cholesteatoma.

OBJECTIVE To investigate and analyze the relationship between individual ossicular erosion and air-bone gap (ABG) among patients with cholesteatoma. STUDY DESIGN Retrospective case review. SETTING Tertiary referral center. SUBJECTS AND METHODS Data from all patients undergoing an initial surgery for cholesteatoma were retrospectively reviewed to evaluate the relationships between preoperative pure tone audiometry data, intraoperative assessment of individual ossicular destruction, and clinical characterization of cholesteatoma. For each patient, the cholesteatoma was categorized as primary acquired, secondary acquired, congenital, or unable to discern. Ossicular destruction was graded, and ABG was calculated. For each ossicle, the relationship between degree of cholesteatoma involvement and ossicular erosion and the ABG was analyzed using univariate and multivariate linear regression. RESULTS A total of 158 primary cholesteatoma surgeries were performed by the senior author between 1992 and 2009 that met our inclusion criteria. The status of each ossicle was significantly associated with the ABG in a graded and independent manner; this association was most significant for the incus. Cholesteatoma abutting an intact ossicle did not significantly affect the ABG. Clinical categorization of cholesteatoma was not significantly associated with the ABG. CONCLUSION Previous assessments of ossicular destruction have provided limited information about the relationship between ossicular destruction and ABG in cholesteatoma patients. Through the use of a new and detailed grading scale, this study reveals that the erosion of each ossicle contributes in a graded and independent manner to the increase in ABG, with the status of the incus having the most statistically significant association with ABG.