Abstract
This study examined the effect of tympanic membrane perforation on conductive disturbances in association with the case of chronic otitis media. The study examined 29 cases of chronic otitis media that underwent only type I tympanoplasty. The size and longer axis of perforation were calculated to determine the perforation area rate and the longer axis ratio using image analysis system. The conductive disturbance was calculated from the gap between the preoperative and postoperative air conduction. The correlations between the conductive disturbance and perforation area rate or longer axis ratio were analyzed. Furthermore, a conductive disturbance index was calculated for the purpose of examining the effect that a perforation size had on a conduction disturbance. The calculated conduction disturbance indices were classified and examined by the shape of the perforation, perforated site, and presence or absence of interference to the malleus. The conductive disturbance grew significantly larger in the low range when the perforation occurred in the eardrum, and it became larger in the presence of inflammatory changes. The effect of a circular perforation on the conductive disturbance was significantly small. However, the effect of a perforation of the anteroinferior quadrant on the conductive disturbance was significantly large in the high range.
