Hearing Outcomes for an Underwater Endoscopic Technique for Transmastoid Repair of Superior Semicircular Canal Dehiscence

By June 7, 2019

Creighton, Francis1; Zhang, Lisa2; Ward, Bryan1; Carey, John1
1 Johns Hopkins Department of Otolaryngology, Baltimore, MD, USA;
2 Johns Hopkins School of Medicine, Baltimore, MD, USA.

To compare hearing outcomes between traditional microscopic transmastoid repairs and a novel underwater, endoscopic technique for transmastoid repairs of superior semicircular canal dehiscence (SSCD).

A retrospective review of 14 patients undergoing transmastoid repair of SSCD between 2013 and 2017. Preoperative, immediate (<7 days) postoperative and long-term (> 6 weeks) postoperative speech discrimination scores (SDS), pure tone averages (PTA), as well as pure tone air conduction (AC) and bone conduction (BC) thresholds were obtained at 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz. Hearing threshold changes were all calculated as pre-operative thresholds subtracted from post-operative threshold at each frequency. Wilcoxon rank-sum tests were conducted to assess changes in post-operative hearing thresholds at both the immediate and long-term post-op between those undergoing the microscopic transmastoid technique and the undergoing underwater, endoscopic transmastoid technique.

In the immediate postoperative period, there were no significant differences in hearing thresholds at any frequency, nor in SDS or PTA between the microscopic verses the underwater transmastoid repair technique (p > 0.0038). At long-term follow-up, a significant difference was found between groups at in PTAs (p = 0.0037). There were no differences in hearing thresholds at any individual frequency nor in SDS.

Preliminary findings show that the underwater endoscopic technique could be a promising technique to limit hearing loss during transmastoid repair of SSCD.