Clinical and Radiographic Predictors of Lateral Semicircular Canal Fistula

Abstract

Objectives:

Lateral semicircular canal fistula (LSCCF) may occur in as many as 10% of patients with cholesteatoma. Despite improvements in diagnostic imaging, reliable preoperative identification of LSCC remains elusive. Our objective is to explore preoperative clinical variables and intraoperative findings in order to identify factors associated with the presence of LSCCF.

Methods:

A retrospective matched cohort study was conducted. All patients with LSCCF, determined by intraoperative diagnosis, that had preoperative temporal bone computed tomography (CT) available for review were identified. Subjects were matched to patients without LSCCF according to age, gender and year of surgery. Associations between LSCCF and preoperative vertigo, fistula test results, sensorineural hearing loss (SNHL), stapes superstructure erosion, facial nerve and dural dehiscence, and preoperative radiographic findings were evaluated.

Results:

Eighty-three patients with LSCCF met inclusion criteria and were matched to subjects without labyrinthine fistula. Patients with LSCCF more commonly had stapes superstructure erosion (34 vs 15, P < .001), facial nerve dehiscence (55 vs 10, P < .0001), and dural dehiscence (29 vs 4, P < .0001) compared to subjects without LSCCF. The presence and severity of preoperative SNHL, vertigo, and fistula test results were unreliable predictors of LSCCF. Furthermore, of those patients with LSCCFs, only 28% were identified on pre-operative CT.

Conclusions:

Preoperative variables including SNHL, vertigo, fistula test results as well as preoperative temporal bone CT were not reliable predictors of LSCCF. However, intraoperative findings including stapes superstructure erosion, facial nerve and dural dehiscence were found to be associated with LSCCF and should raise suspicion of disease.