Relationship between size and site of tympanic membrane perforations and pure tone audiometry results

Background: Chronic otitis media is a condition commonly presenting with tympanic membrane perforation and resulting in conductive hearing loss. The aim of the study was to assess the relationship between the site and size of tympanic membrane perforation with the degree of hearing impairment in patients with inactive chronic otitis media of mucosal type. Methods: Hospital based cross sectional study of 174 patients with tympanic membrane perforation at government medical college, Alappuzha from November 2017 to March 2019. Patients were enrolled based on history and clinical examination findings. Images obtained by otoendoscopy were analyzed by measuring the percentage area of membrane perforation in relation to total area of the tympanic membrane using adobe acrobat area tool. Degree of hearing loss was calculated by pure tone audiometry test and calculating the average hearing thresholds at frequencies of 500Hz, 1000Hz, 2000Hz and 4000Hz. Results: The age distribution of patients ranged from 14 to 72 years with a mean age of 41.78years. Male to female ratio was 1.59:1. The degree of hearing loss increased as the size of the perforation increased which was statistically significant (p <0.001). Posterior quadrant perforations resulted in more hearing impairment than anterior quadrant perforations. Conclusion: The size of the tympanic membrane perforation is closely related to the degree of hearing loss and posterior quadrant perforations have more degree of hearing impairment than anterior quadrant perforations which signifies improvement in hearing in patients with chronic otitis media by reconstructive surgeries, especially for perforations involving the posterior quadrant.