[Topical anesthesia of the tympanic membrane and tubal function--is there a correlation?]

The influence of topical anaesthesia of the tympanic membrane on Eustachian tube function was investigated using the pressure chamber impedance method, thus obtaining quantitative data. Anaesthesia was performed by application to the tympanic membrane of small cotton balls containing lidocaine and dimethylsulfoxide. We did not observe significant alterations of tubal parameters after unilateral or bilateral anaesthesia. Our observations are in contrast to investigations published by Nagai. We suppose that differences in methods of topical anaesthesia are responsible for this discrepancy. Our technique of topical anaesthesia of the tympanic membrane excludes any effect on the Eustachian tube, thereby avoiding negative consequences of middle ear pressure on wound healing.