Continuity of the incudostapedial joint: a novel prognostic factor in postoperative hearing outcomes in congenital aural atresia

Conclusion: Mean incudostapedial joint (ISJ) angulation of atretic ears was statistically wider than ISJ angulation of non-atretic ears. Postoperative hearing results in the narrow tympanoplasty type II (T2) subgroup were better than those in the wide T2 subgroup. In cases of abnormally wide ISJ angulation, we recommend that partial ossicular reconstruction (POR) be used as a surgical means of achieving hearing improvement. Objective: To report the results of ISJ angulation in patients with congenital aural atresia and its effects on postoperative hearing improvement. Methods: Patients undergoing canaloplasty with T2 (149 ears) and canaloplasty with POR (32 ears) were enrolled. The T2 group was dichotomized according to an ISJ cut-off of an angle of 120 degrees into the 'narrow' T2 and 'wide' T2 subgroups. The pre- and postoperative air-bone gap (ABG) and ABG change were analyzed. Results: Mean ISJ angulation of non-atretic ears was 93.06 +/- 13.21 degrees and that of atretic ears in the T2 group was 118.39 +/- 19.60 degrees (p < 0.001). Mean short-and long-term postoperative ABGs were better in the narrow T2 subgroup than in the wide T2 subgroup (p = 0.01 and 0.03, respectively). The short-term postoperative ABG and ABG change in the POR showed superior results to those of the wide T2 subgroup (p < 0.001 and 0.041, respectively).