Otic capsule dehiscence syndrome: Superior semicircular canal dehiscence syndrome with no radiographically visible dehiscence.

Abstract

We conducted a prospective longitudinal study of two cohorts of patients who had superior semicircular canal dehiscence syndrome (SSCDS); one group had radiographically confirmed superior canal dehiscence (SCD), and the other exhibited no identified otic capsule dehiscence on imaging (no-iOCD). We compiled data obtained from prospective structured symptomatology interviews; diagnostic studies; three-dimensional, high-resolution, temporal bone computed tomography; and a retrospective case review from our tertiary care referral center. Eleven adults and 1 child with SSCDS were identified, surgically managed, and followed. Six of these patients-1 man and 5 women, aged 29 to 54 years at first surgery (mean: 41.8)-had radiologically confirmed SCD. The other 6 patients-1 man, 4 women, and 1 girl, aged 1 to 51 years (mean: 32.2)-had no-iOCD. The 6 adults with SCD underwent surgery via a middle cranial fossa approach with plugging procedures. The 5 adults and 1 child with no-iOCD underwent round window reinforcement (RWR) surgery. One SCD patient developed no-iOCD 1.5 years after SCD surgery, and she subsequently underwent RWR surgery. Our main outcome measures were patient symptomatology (with video documentation) and the results of diagnostic studies. Other than the character of migraine headaches, there was no difference in preoperative symptomatology between the two groups. Postoperatively, resolution of SSCDS symptoms ultimately occurred in all patients. Both the SCD and the no-iOCD groups experienced a highly significant improvement in postural control following treatment (Wilcoxon signed rank test, p < 0.001). We conclude that the term otic capsule dehiscence syndrome more accurately reflects the clinical syndrome of SSCDS since it includes both superior semicircular canal dehiscence and no-iOCD, as well as posterior and lateral semicircular canal dehiscence, all of which can manifest as SSCDS. We have also included links to videos in which 4 of the SSCDS patients with no-iOCD in this study discussed their symptoms and the results of their surgery; these links are found in the "References" section in citations 12-15. Links to three other videos of interest are contained in citations 10, 11, and 24.