Superior canal dehiscence syndrome: clinical manifestations and radiologic correlations

The objective of this study is to describe the superior canal dehiscence syndrome (SCDS) and its vestibule-cochlear manifestations, while analyzing dehiscence size, audiogram and vestibular-evoked myogenic potential (VEMP) changes following dehiscence obliteration. We conducted a prospective study in a tertiary referral center. All Patients diagnosed and surgically treated for SCDS were operated through a middle fossa craniotomy (MFC). Clinical and radiological data were collected. The main outcome measures were Air-bone gaps, Pure-tone average (PTA), speech discrimination scores (SDS) and VEMP thresholds and were correlated to dehiscence size. 28 patients were included in this study with a mean dehiscence size of 4.68 mm. Phonophobia and imbalance were the most debilitating cochlear and vestibular symptoms, respectively. At 2 months postoperatively, low-frequency air-bone gaps showed a statistically significant improvement (p < 0.001). SDS and PTA did not show any statistically significant changes 2 months postoperatively (p = 0.282 and p = 0.295, respectively). VEMP threshold differences between operated and contralateral ears were statistically significant preoperatively (p < 0.001) and non-significant 2 months postoperatively (p = 0.173). Dehiscence size only showed a statistically significant correlation with preoperative total cochlear symptoms, while remaining insignificant with all other variables measured. Air-bone gaps, VEMP and computerized tomography remain essential tools in diagnosing and following SCDS. Dehiscence size is an independent factor in the analysis of SCDS, with cochlear symptomatology being associated to dehiscence sizes. Finally, it is shown that overall symptomatology, audiometric results and VEMP thresholds return to normal values post-obliteration, confirming the continuing success of the MFC approach for SCDS obliteration.