Facial canal dehiscence in cholesteatoma and co-existing surgical findings: a systematic review and meta-analysis

Background: Dehiscence of the facial canal is an important consideration in cholesteatoma surgery. This study aims to determine the prevalence of intra-operative finding of facial canal dehiscence (FCD) in patients with cholesteatoma who underwent middle ear surgery, and to investigate surgical findings that are associated with FCD.Methods: The systematic review and meta-analysis was conducted in accordance with the PRSIMA guidelines using the following databases: PubMed, MEDLINE, Embase, and Cochrane Library. The search was completed on 25th October 2021. The selection criteria included studies published in the English literature between 1981-2021 that reported FCD incidence diagnosed intraoperatively during middle ear surgery for cholesteatomatous disease. The pooled prevalence was calculated using a generic inverse variance model with random effects analysis. The Joanna Briggs Institute (JBI) checklist for prevalence studies was used for quality assessment of included articles.Results: Twenty-seven articles representing 5,848 cases were included for quantitative analysis, with two outliers identified on leave-one-out analysis and excluded. The pooled prevalence of FCD was found to be 24.67% [95% confidence interval (CI): 21.51-27.84%]. The overwhelming majority of dehiscence occurred in the tympanic segment of the facial canal with a pooled prevalence of 93.79% (95% CI: 92.06-95.52%). The prevalence of FCD was comparatively higher in adult, 27.20% (95% CI: 22.18-32.22%) versus paediatric, 15.33% (95% CI: 8.86-21.79%) patients, in revision, 33.54% (95% CI: 27.30-39.78%) versus primary, 24.47% (95% CI: 21.27-27.66%) surgery, and in studies with smaller sample size <300 patients, 26.60% (95% CI: 22.12-31.07%) versus larger sample size, 21.94% (95% CI: 18.14-25.74%). A metaanalysis of twelve studies showed that the presence of a lateral semicircular canal fistula increased the likelihood of FCD with an OR 6.45 (95% CI: 4.07-10.23).Conclusions: FCD is a common finding during cholesteatoma surgery with increased likelihood in adult and revision cases. Studies have reported an association with other destructive findings to middle ear structures, including the scutum, ossicles, and semicircular canals, highlighting the importance of preoperative clinical and radiographic evaluation to assess the risk of dehiscence.