Risk of progressive hearing loss in untreated superior semicircular canal dehiscence

Patients with incidental or minimally symptomatic superior semicircular canal dehiscence (SSCD) are usually observed, without surgical repair. However, it remains unknown whether a labyrinthine fistula of the superior semicircular canal is associated with progressive conductive or sensorineural hearing loss over time.

Retrospective review at two tertiary care academic referral centers.

Adults analyzed were diagnosed with SSCD by high-resolution temporal bone computed tomography and vestibular evoked myogenic potential testing and observed with a minimum of two sequential audiograms. Patients with other potential causes of hearing impairment were excluded.

A total of 40 ears in 30 adult patients (median age: 59 years; 63% female) were analyzed. Median audiometric follow-up was 23 months (range 1-136 months). None experienced a sudden hearing loss over the follow-up period. In patients with audiometric follow-up of at least 20 months (median 34 months), the median change in air-conduction pure tone average and air-bone gap was 0.9 decibels (dB) per year (interquartile range [IQR] 0-2.1) and 0.7 dB per year (IQR 0-2.0), respectively. Speech discrimination scores did not differ when comparing median initial (100%) and median final (98%) scores (P = 0.77). There was no statistically significant change in bone-conduction thresholds at 0.5, 1, 2, and 4 kHz over the period of observation.

The risk of progressive hearing loss with observed SSCD is low during short- and intermediate-term follow-up. Further studies are necessary to determine whether late hearing loss occurs. Such information may be critical toward patient counseling regarding the need for and timing of surgery.

4. Laryngoscope, 127:1181-1186, 2017.