Study of Predictive Value of Middle Ear Risk Index on Hearing Improvement in Patients Undergoing Surgery for Chronic Suppurative Otitis Media

Abstract

Introduction: Middle ear risk index is one of the most reliable measuring tools to predict and evaluate the results of tympanoplasty. This study was done to analyse the predictive value of revised middle ear risk index on hearing improvement in patients undergoing surgery for chronic otitis media and to correlate the association between each index factor with hearing results. Materials and Methods: This prospective observational study was done over 2 years in a tertiary care Army Hospital with 88 patients in the age group of 10-65 years. Preoperative hearing thresholds and air-bone gaps were recorded. Patients were assigned to mild, moderate and severe groups with risk index scores. Hearing thresholds were assessed at 3 and 6 months following surgery for chronic otitis media. Data was statistically analysed. Results: 92.04% and 77.27% showed hearing improvements, 4.54% and 1.13% had deterioration and 3.40% and 21.59% had no change when compared to preoperative results in AC and BC thresholds respectively. 57.95% had post-operative closure of air bone gap of ≤ 12. Compared to cases with AB gap closure ≤ 12, those with AB gap closure > 12 showed statistically significant gain in BC by 0.2dB. Each unit increase in risk index score was associated with statistically significant increase of 0.64 dB in BC. Out of the seven individual factors, only perforation and previous surgery showed statistical significance in terms of hearing improvement. Conclusion: Middle ear risk index is not a good predictor of hearing improvement in ear surgery. Individually, risk index or air bone gap are not strong predictors but jointly, they show strong association with hearing improvement both in terms of AC and BC. Keywords: Middle ear risk index; Air conduction; Bone conduction; Air-bone gap; Hearing improvement.