Underwater Endoscopic Repair of Superior Canal Dehiscence

: Superior canal dehiscence (SCD) is a bony defect of the superior semicircular canal (SCC). Patients with SCD Syndrome (SCDS) may experience symptoms such as aural fullness, pulsatile tinnitus, hyperacusis, autophony, or pressure or noise-induced vertigo . The defect can be repaired in various ways, but there is potential for loss of perilymphatic fluid during transmastoid approaches that could result in postoperative sensorineural hearing loss . We hypothesize that if the procedure were performed "underwater" in balanced salt solution (BSS), loss of perilymphatic fluid would be minimized. CASE REPORT:: A 55-year-old male presented with right-sided autophony, pulsatile tinnitus, and hyperacusis. Audiometric testing demonstrated a low-frequency airbone gap and a supranormal bone-conduction threshold at 4 kHz. Ocular VEMP responses were increased amplitude. Temporal bone imaging revealed a SCC dehiscence.The patient was taken to the operating room for an underwater, endoscopic repair of the SCC using a transmastoid approach. A cortical mastoidectomy was performed using Landmarx image navigation. BSS filled the mastoid and a 0-degree endoscope with endoscrub was used to see the SCC underwater. The SCC was entered near the ampullated end with a bur. A stepwise plugging process included applying strips of wet and dried fascia and bone dust. The non-ampullated end was similarly plugged. BSS was suctioned, and under microscopic visualization, labyrinthotomies were capped with bone chips. The patient tolerated the procedure well and was discharged the next day. There was no sensorineural hearing loss postoperatively. CONCLUSION:: SCDS may be addressed surgically using multiple approaches. An underwater endoscopic repair of the SCC may be safe and effective surgical treatment.SDC video link: http://links.lww.com/MAO/A808.