Investigation of ambient-pressure absorbance characteristics of cartilage-grafted tympanic membranes

Abstract

Abstract Objective To investigate alterations in middle-ear mechanics after type 1 cartilage tympanoplasty by comparing the ambient pressure absorbance values of the perforated tympanic membrane, normal tympanic membrane and cartilage-grafted tympanic membrane. Methods Twenty patients diagnosed with non-suppurative chronic otitis media and 20 healthy controls were included. Pure tone audiometry and wideband tympanometry were performed once in the healthy controls and pre-operatively, one month and three months post-operatively in the patients. Results Using wideband tympanometry, the patients’ three-month post-operative ambient pressure absorbance values were found to be similar to those of the healthy controls at low frequencies, while lower ambient pressure absorbance values were recorded at middle and high frequencies. Air–bone gap and ambient pressure absorbance values showed significant negative correlations at 1000 and 4000 Hz both pre- and post-operatively. Conclusion Generally, the patients’ ambient pressure absorbance values were significantly lower at middle and high frequencies than those of the healthy controls. Post-operative wideband tympanometry is a practical tool for investigating the effects of a repaired tympanic membrane on middle-ear dynamics.