Revision Surgery for Superior Canal Dehiscence Syndrome

Objective: To identify factors associated with surgical failure for superior canal dehiscence syndrome (SCDS) and define rates of complications and cure after revision SCDS repair. Study Design: Retrospective patient series. Setting: Tertiary care referral center. Patients: Adults who underwent revision surgery for SCDS. Interventions: None. Main Outcome Measures: Initial surgical approach, intraoperative findings at the time of revision, persistence of symptoms, and complications for revision surgery. Results: Two hundred twenty-two surgical SCDS patients were identified, including 21 subjects who underwent 23 revision surgeries. Fourteen (61%) underwent previous middle fossa and nine (39%) underwent previous transmastoid approaches. Intraoperative findings showed that in 17 (74%) the previous material used to plug or resurface the canal was present but not entirely covering the dehiscence. In one (4%) the material was not present. In one (4%) the material was in proper position, whereas in four (17%) the material was in proper position with very thin bone adjacent. After revision surgery, symptoms were completely resolved in eight (35%), partially resolved in seven (30%), and not resolved in seven (30%). Findings of thin bone adjacent to the previous plug was associated with failure of symptom resolution (p = 0.03). Hearing outcomes were compared to a previously studied cohort of primary surgery patients, and outcomes were similar. Three subjects (13%) had a significant decrease in their word recognition score after revision surgery (p=0.52), and seven (30%) had a significant increase in their pure-tone average (p=0.78). Conclusion: Revision surgery for SCDS can be curative in carefully selected patients, but there may be a higher failure rate than primary surgery, with similar hearing outcomes.