Transmastoid Approach for Repair of Superior Semicircular Canal Dehiscence

Objective The current operative modality used to treat auditory and vestibular symptoms of superior semicircular canal dehiscence (SSCD) is through a middle cranial fossa (MCF) approach. Literature reports of an alternate transmastoid (TM) approach has emerged with comparative success rates. Here, the authors summarize clinical outcomes for the TM approach.

Methods A literature search was conducted using PRISMA guidelines to find patients who underwent SSCD repair through a transmastoid approach. A total of 15 articles with 73 patients resulted with 11 studies and 61 patients ultimately included in quantitative analysis of outcomes. Outcomes of interest included auditory symptoms of pulsatile tinnitus, aural fullness, autophony, hearing loss, and hyperacusis. Vestibular symptoms included nystagmus and vertigo (either pressure, sound, or Valsalva induced), oscillopsia, and chronic disequilibrium.

Results The average age of these individuals was 49.2 years (SD: 10.7, range: 31–76), with 25 males and 36 females. 78.7% of patients had resolution of 1 or more symptoms with 37.7% expressing resolution of all symptoms. Of the remaining patients, 13% had no change in symptoms after surgery with five patients reporting additional symptoms. There was a trend with more women having dizziness after surgery than men (p = 0.09, OR: 0.64, 95% CI: 0.41–0.99). With regard to approach, transmastoid surgery for treatment of SSCD was not associated with complications when performed unilaterally or bilaterally on patients. There were no significant complications arising from intraoperative techniques such as plugging or resurfacing.

Conclusion The authors sought to determine the safety and efficacy of the transmastoid approach to SSCD repair compared with the current standard of care. Patients improved in symptomology at a rate of 78.7% in line with previous studies reporting success rates in TM surgery. No auditory or vestibular outcomes were significantly associated with this approach, with similar rates of symptom resolution to the currently favored MCF approach. Notably, no symptoms associated with the MCF approach such as bleeds or seizures were reported showing that the TM approach circumvents these more damaging complications. A transmastoid approach offers the advantages of shorter operative duration, hospital stay, cosmetic appeal with a smaller incision, and cost-effectiveness for the patient. While these factors offer support for the use of TM as a primary surgical measure, the choice ultimately depends on the surgeon, the location of the dehiscence, and the unique anatomy of the patient. More studies determining the efficacy of the TM approach are needed to corroborate these findings