Surgical results of 29 ears with congenital middle ear anomalies; Microscopic vs. endoscopic ear surgery

Although congenital middle ear anomalies include various types of ossicular anomalies, all of these can be treated by ossiculoplasty or stapes surgery. Transcanal endoscopic ear surgery (TEES) is a minimally invasive surgical method for middle ear disease with an excellent surgical view that has been widely adopted worldwide. To determine the efficacy of TEES for middle ear anomalies, we describe the surgical results and compare the hearing outcomes between patients treated by TEES and microscopic ear surgery (MES).A total of 39 ears with congenital middle ear anomalies were treated surgically at the University Hospital of Kochi Medical School between January 2011 and December 2021. In total, 29 ears of 23 patients were included in the study. Demographics, type of anomaly, surgical methods, pre- and postoperative hearing thresholds, and surgical complications were investigated by retrospective chart review.Of the 29 ears, 11 were treated by MES and 18 were treated by TEES. There were no differences in sex, age, preoperative hearing thresholds, or rate of stapes surgery between the two groups. The mean air-bone gap improvement was 20.6 dB in the MES group and 28.8 dB in the TEES group; these values were not significantly different. The median operation time was not significantly different between the MES and TEES groups (125 and 130 min, respectively). The improvements of air conduction in class 1 and 2 (stapes surgery) and class 3 (ossiculoplasty) cases were also not different between the groups.TEES achieved comparable hearing outcomes to MES without postauricular or endaural incisions. Further, class 1 and 2 anomalies demonstrated hearing improvement similar to class 3 without major complications. Since the surgical field limited around the ossicular chain, coupled with the fact that the middle ear anomaly itself does not exhibit inflammation leading to unfavorable bleeding, TEES is a feasible surgical procedure for all types of congenital ossicular anomalies.