Functional Correlations of Tympanic Membrane Perforation Size

Objective: The correlation between tympanic membrane perforations and hearing loss was studied. Study Design: Prospective data from 220 patients, who underwent primary surgery for simple chronic otitis media with a perforated eardrum, were analyzed. Setting: Tertiary referral center. Patients: One hundred fifty-one patients with 155 eardrum perforations, which were checked for correct diagnosis, normal middle-ear status, and integrity of the ossicular chain, were included. Interventions: All patients underwent primary myringoplasty. Main Outcome Measures: Preoperative conductive hearing loss due to eardrum perforations. Results: Hearing loss shows a linear relationship with increasing eardrum perforation size. Umbo involvement shows a worsening of the hearing by 5 to 6 dB (p < 0.0001). The least impact of a perforation is seen at the resonance frequency of 2 kHz. Above and below 2 kHz, an inverted V shape of the air-bone gap is a consistent finding. If the air-bone gap exceeds the inverted V-shape pattern, additional pathology behind the eardrum must be assumed and addressed. Conclusion: We propose using standardized photographs or drawings to document preoperative perforation sizes. A linear relationship between the size of a perforation and the conductive hearing loss does exist. Umbo involvement at the perforation margin may worsen the hearing by 5 to 6 dB, whereas the position of the perforation itself does not play a role. The least impact of a perforation is seen at the resonance frequency of 2 kHz. An inverted V-shape pattern, above and below 2 kHz, of the air-bone gap is a consistent finding. If the air-bone gap exceeds this pattern, additional pathology behind the eardrum perforation must be assumed and addressed.