Can ear irrigation cause rupture of the normal tympanic membrane?: an experimental study in man.

Rupture of the tympanic membrane (TM) during ear irrigation is a rare but unhappy event. In this study the maximum overpressures obtained in the deep part of the external auditory meatus (EAM) during ear irrigation were measured postmortem in 20 cadavers. The highest pressures were obtained in normal- or wide-dimension EAMs when a metal syringe was used. With this device, the median maximum overpressure was 240 mmHg (range 200-300 mmHg). Experiments with simulation of an obturating wax plug did not increase the maximum overpressure. Compared with the lowest overpressures which can rupture TMs the pressures measured in this study were insufficient to rupture normal TMs but sufficient to rupture atrophic TMs with the lowest tensile strength. This finding may have medicolegal implications.