Correlation between functional outcome and the {SAMEO}-{ATO} framework

Purpose: To evaluate the recently proposed SAMEO-ATO framework for middle ear and mastoid surgery, by correlating it with the functional outcome in a large cohort of patients operated for middle ear and mastoid cholesteatoma in a tertiary referral center. Methods: We retrospectively included all surgeries for middle ear and mastoid cholesteatoma undergone in our Department between January 2009 and December 2014, by excluding revision surgeries, congenital and petrous bone cholesteatoma. All surgeries were classified according to the SAMEO-ATO framework. The post-operative air bone gap (ABG) was calculated and chosen as benchmark parameter for the correlation analysis. Results: 282 consecutive surgeries for middle ear and mastoid cholesteatoma were released in the study period on a total of 273 patients, with a mean age of 41.2 years. All patients were followed for an average period of 55.3 months. 54% of patients underwent M2c mastoidectomy (Canal Wall Down, CWD), while the remaining underwent Canal Wall Up (CWU) procedures, being M1b2a mastoidectomy the most common one (33%). Mean pre-operative and post-operative ABGs were 29.2 and 23.5 dB, with a significant improvement (p < 0.0001). 'Mastoidectomy' and 'Ossicular reconstruction' parameters of SAMEO-ATO showed significant association with postoperative ABG, with smaller residual gaps for the classes Mx and On, and worse hearing results for M3a and Ox. Conclusion: Our results show the utility of SAMEO-ATO framework, and in particular of 'M' (Mastoidectomy) and 'O' (Ossicular reconstruction) parameters, in predicting the hearing outcome