Traumatic Pneumolabyrinth: Air Location and Hearing Outcome

Objective: To describe 3 cases of pneumolabyrinth after penetrating injury to the middle ear and to review previously reported cases, comparing precipitating factors and hearing outcomes. Data Sources: Three cases we encountered and the PubMed and Japan Medical Abstracts Society databases. Study Selections: In addition to our 3 cases, we identified 48 cases from 41 articles regarding pneumolabyrinth. Data Extractions: All articles describing cases of pneumolabyrinth were used for this review. Data Synthesis: Among the 51 cases, audiologic evaluation was not available in 16 cases. In the remaining 35 cases, hearing outcomes were analyzed focusing on 3 factors: 1) differences in and interval until medical intervention, 2) existence of stapes lesions, and 3) extension of air bubble into the inner ear. We failed to find any significant differences in interventions, although operation less than 2 weeks after injury tended to be associated with a higher rate of hearing recovery (54%) than operation 2 weeks or longer after injury (25%). Furthermore, 11 (48%) of 23 cases with pneumolabyrinth limited to the vestibule or semicircular canals showed improved hearing, whereas none of 6 cases (0%) with pneumolabyrinth extending from the vestibular organs to the cochlea showed hearing recovery. This difference was statistically significant (p < 0.05). Conclusion: Assessment of the location and extension of pneumolabyrinth appears important in predicting hearing outcomes and planning the management of middle and inner ear trauma.