Transcanal Endoscopic Ear Surgery for Conductive Hearing Loss in Postoperative Ears: A Report of Two Cases

Revision middle ear surgery for persistent conductive hearing loss after previous tympanoplasty or ossiculoplasty is technically demanding because of scar tissue, anatomical distortion, and the unpredictable status of the ossicular chain. Although transcanal endoscopic ear surgery (TEES) has been increasingly adopted for primary tympanoplasty and ossiculoplasty, its feasibility as the sole surgical modality in postoperative ears has rarely been reported.

We describe two adult patients (Case 1: a 63-year-old man and Case 2: a 72-year-old man) who presented with long-standing conductive hearing loss in dry, well-aerated postoperative ears following previous tympanoplasty performed at outside institutions. Preoperative four-frequency pure-tone average (PTA) air-bone gaps (ABGs) ranged from 28.75 to 40.00 dB (mean, 34.38 dB) with preserved bone-conduction (BC) thresholds. In both patients, TEES was performed exclusively through a minimal skin incision just above the tympanic membrane, without a retroauricular approach. Intraoperatively, fixation of the ossicular chain involved not only the previously placed columella but also the native ossicles, requiring complete release in each case. Type III tympanoplasty was performed in both cases. According to the IOOG SAMEO-ATO framework, both procedures were classified as S2r A1 Mx Ex Ox Ax Tx Ost.

The mean four-frequency PTA air-conduction threshold improved from 66.25 dB preoperatively to 42.19 dB postoperatively (mean hearing gain, 24.07 dB), and the mean postoperative ABG was reduced to 10.32 dB (range, 8.75-11.88 dB). Both patients (100%) fulfilled the criteria for postoperative hearing improvement according to the 2010 guidelines of the Japan Otological Society. No intraoperative or postoperative complications-including facial nerve injury, sensorineural hearing loss, dysgeusia, or vertigo-were observed during the follow-up period (mean, 18.5 months; range, 12-25 months).

In carefully selected postoperative ears with a dry middle ear and good BC reserve, TEES may serve as a useful minimally invasive alternative to the conventional retroauricular microscopic approach, offering advantages in surgical visualization, operability, and reduced invasiveness. Larger studies are warranted to define optimal indications and long-term outcomes.