Pneumolabyrinth as an Early Computed Tomographic Finding After Cochlear Implantation and its Clinical Significance

Objective: To determine the incidence and volume of pneumolabyrinth using early temporal bone computed tomography (TBCT) findings and evaluate the correlation between pneumolabyrinth and various clinical variables. Study Design: Retrospective case review. Setting: Tertiary academic center. Patients: Fifty-three consecutive adult cochlear implantation (CI) recipients (53 ears) with normal inner ears who underwent high-resolution TBCT within 3 days after CI were included. Intervention: Axial TBCT images were used for detection and measurement of pneumolabyrinth. Main Outcome Measures: Incidence and volume of pneumolabyrinth were evaluated. In addition, the following clinical variables were analyzed to evaluate the correlation with pneumolabyrinth volume: demographics, implant type, surgical approach, postoperative dizziness, and preservation of functional residual hearing. Results: Pneumolabyrinth was present in all patients, and the average volume was 8.496 mm(3). Pneumolabyrinth was confined to the cochlea (pneumocochlea) in all patients except for one who also had pneumovestibule. The pneumolabyrinth volume in patients with postoperative dizziness was significantly larger than that in patients without postoperative dizziness (10.435 mm(3) vs. 8.016 mm(3); p = 0.029). Multivariate analysis showed that a larger volume of pneumolabyrinth was significantly associated with postoperative dizziness (odds ratio, 1.420; 95% confidence interval, 1.114-1.808; p = 0.005). Conclusion: A certain volume of pneumolabyrinth was always present in the early stage after CI, and the volume of pneumolabyrinth measured using early TBCT findings was significantly associated with the occurrence of postoperative dizziness.