Objectives: We analyzed several radiological features of the facial recess to correlate them with the intraoperative findings to highlight the most reliable predictors of posterior tympanotomy difficulty.
Study design: Retrospective observational cohort study.
Setting: Multicenter study at tertiary referral institutions.
Methods: We included 184 pediatric patients who underwent cochlear implantation through the posterior tympanotomy approach. The correlation was attempted between 8 radiological features in the preoperative high-resolution computed tomography scan and intraoperative surgical difficulty.
Results: Posterior tympanotomy was straightforward in 136 (73.9%) patients. In contrast, it was challenging in 48 (26.1%) patients. The facial recess was aerated in 74.5% of patients. The mean (SD) posterior tympanotomy depth was 3.98 (0.867) mm. The mean (SD) chorda-facial angle was 27.67° (3.406°). The mean (SD) chorda-facial to stylomastoid length was 3.898 (0.6304) mm. The mean (SD) facial nerve second genu angle was 94.54° (6.631)°. Deep-unaerated facial recess wall was associated with the most difficulty. There was a statistically significant difference in the unchallenging and challenging posterior tympanotomy groups regarding the surgical duration (P < .0001).
Conclusions: According to this analytic study, the chorda-facial angle, the facial recess aeration, and the chorda-facial to stylomastoid length were respectively the strongest preoperative radiological predictors of the surgical difficulty of posterior tympanotomy during cochlear implantation. Chorda-facial angle <25.5° was associated with difficult posterior tympanotomy. The oblique parasagittal cut was essential for the radiological analysis of the facial recess.
Keywords: CT scan; cochlear implant; facial recess; posterior tympanotomy; prediction.