Comparing Approaches for Repair of Superior Semicircular Canal Dehiscence

Introduction: Compare surgical and audiometric outcomes between middle cranial fossa (MCF) and transmastoid (TM) approaches for repair of superior semicircular canal dehiscence (SSCD).

Methods: A retrospective, case-control study of all patients that received middle cranial fossa (MCF) or transmastoid (TM) surgical intervention for the treatment of SSCD between January 1999 and December 2022 was performed at a tertiary-care, academic medical center. The main outcome measures included demographic data, length of surgery, length of hospital stay, and preoperative and postoperative symptoms and audiometric testing. Comparative analyses were performed with Mann-Whitney U test, as data were not normally distributed.

Results: Ninety-four subjects underwent surgery for SSCD: 64% (60) via a MCF and 36% (34) via a TM approach. Median age at diagnosis was 45 years (IQR 37-54.5 years) for MCF and 50 years (IQR 41.5-66 years) for TM (p=0.026). The median operative time was significantly shorter for the TM compared to the MCF approach (120 minutes, IQR 103-136 minutes vs. 151 minutes, IQR 136-173 minutes, p< 0.001). The median hospital stays were also significantly shorter for TM compared to MCF (1 day, IQR 0-1 day vs. 3 days, IQR 1-3 days, p< 0.001). Furthermore, 44 % (15) of TM surgeries were outpatient. In the MCF group, median pure tone average (PTA) was 23 dB preoperatively and 19 dB postoperatively (p=0.716); median word recognition score (WRS) was 100% preoperatively and 100% postoperatively (p=0.192). In the TM group, median PTA was 20 dB HL preoperatively and 25 dB HL postoperatively (p=0.526); median WRS was 100% preoperatively and 96% postoperatively (p=0.154). Among all patients with postoperative follow-up visits, 91% (84) had improved or resolution of symptoms.

Conclusions: The TM approach for SSCD demonstrates shorter operative times and length of stay. The TM and MCF approaches have comparable audiometric outcomes.