The Prevalence of Superior Semicircular Canal Dehiscence in Patients With Mastoid Encephalocele or Cerebrospinal Fluid Otorrhea.

OBJECTIVE

To evaluate the association between mastoid encephalocele or cerebrospinal fluid (CSF) otorrhea and concurrent superior semicircular canal dehiscence (SSCD).

STUDY

DESIGN

Retrospective case-control study with chart and imaging review.

SETTING

University-affiliated tertiary referral center.

PATIENTS: A chart review was conducted of all patients greater than 18 years of age who had primary surgery for CSF otorrhea or encephalocele at our university-affiliated tertiary center from 2000 to 2016. Eighty-three patients matched inclusion criteria for case subjects, and 100 patients without CSF otorrhea or encephalocele were included for controls.

MAIN OUTCOME MEASURE: High-resolution computed tomography (CT) scans were reviewed to assess superior semicircular canal roof integrity. Student's t test was used to determine significance of continuous variables. Odds ratio (OR) and χ test was used to determine the association between SSCD and concurrent mastoid encephalocele or CSF otorrhea compared with the control population.

RESULTS

The mean age of the 83 case subjects was 54 years, and 73% were women. In patients with confirmed encephalocele and CSF otorrhea, the prevalence of SSCD was 35%, which was significantly greater than controls (2%) (OR = 26.1, p < 0.001). In patients with only CSF otorrhea, 21% had concurrent SSCD (OR = 10.3, p = 0.001). In patients with SSCD, 46% had bilateral canal dehiscence.

CONCLUSIONS

This is the largest study to evaluate the prevalence of SSCD in patients with concurrent mastoid encephalocele. This study showed a significant association between SSCD and the presence of both mastoid encephalocele and CSF otorrhea. This data suggests that surgeons should have a high suspicion for SSCD in patients presenting with encephalocele or CSF otorrhea.