Surgical Outcomes Following Transmastoid Approach for Repair of Superior Semicircular Canal Dehiscence

Background: Superior semicircular canal dehiscence syndrome (SCDS) is characterized by a variety of symptoms resulting from an absence of bone overlying the superior semicircular canal. Since the syndrome was first described by Minor in 1998, the surgical management of SCDS has continued to evolve with several techniques described including resurfacing, plugging, or a combination of these two methods. Although repair of superior semicircular canal dehiscence was first described using a middle cranial fossa extradural approach, the ability to perform superior semicircular canal dehiscence repair as an outpatient procedure utilizing transmastoid technique while obviating the need for middle fossa craniotomy and its associated risks has clear advantages. In spite of significant progression in the techniques employed, the optimal surgical approach for the management of SCDS has yet to be determined. Therefore, we aim to review our institutional experience with the surgical management of SCDS and examine audiometric and vestibular outcomes, symptom control rates, complication rates, and length of hospital stay.

Methods: Retrospective chart review of patients undergoing repair of superior semicircular canal dehiscence via middle cranial fossa or transmastoid approach at two academic tertiary referral centers between 2010 and 2015. SCDS was confirmed by correlation of clinical symptoms and audiometric, vestibular testing, and imaging findings. Pre- and post-operative audiometry, vestibular testing, imaging characteristics, operative findings and technique, and clinical symptoms were assessed.

Conclusions: Transmastoid technique for repair of superior semicircular canal dehiscence is a safe and effective alternative to the standard middle cranial fossa approach. The less-invasive transmastoid approach spares the patient the risks associated with middle fossa craniotomy and has the potential to decrease duration of hospitalization. One limitation of the transmastoid approach is restricted access to a dehiscence of the ampullated end of the superior semicircular canal. Although larger, controlled studies are needed, transmastoid approach should be strongly considered in cases of superior semicircular canal dehiscence.