Hearing Preservation in Patients Who Undergo Labyrinthectomy and Translabyrinthine Procedures: A Case Report and Systematic Review.

Importance: Preservation of endolymphatic fluids, maintenance of a fluid-filled vestibule, and preservation of the cochlear nerve and its vasculature are believed to be necessary to retaining hearing after an inner-ear operation. However, some studies have reported no hearing loss despite the violation of the vestibule, questioning the importance of maintaining a fluid-filled vestibule in preserving hearing.

Objective: To report on the preservation of hearing after a complete labyrinthectomy for Meniere disease and after disruption of the vestibule.

Evidence Review: This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. A search of PubMed, Scopus, Ovid, and Cochrane Library databases was conducted to identify English-language articles on hearing preservation after labyrinthectomy, published from 1947 through December 11, 2019. The search strategy used a combination of boolean operators and included the following Medical Subject Heading terms and keywords: hearing preservation, labyrinth surgery, labyrinthectomy, vestibule violation, vestibule disruption, translabyrinthine approach, schwannoma removal, and semicircular canal ablation. Studies that included disruption of the vestibule and hearing preservation were included.

Findings: This systematic review identified 10 studies with 10 patients who underwent surgical removal of cholesteatoma or vestibular schwannoma and displayed postoperative hearing preservation. This study also reported on 1 patient with Meniere disease who retained hearing after undergoing a complete labyrinthectomy. Among these 11 patients, the mean (range) age was 45.1 (27-55) years, and 8 patients (73%) were women. Multiple theories exist that explain the mechanism behind hearing preservation, such as sealing of the ductus reuniens or closure of the remaining vestibule.

Conclusions and Relevance: This systematic review describes a set of patients who did not experience hearing loss after a labyrinthectomy or surgical violation of the vestibule, which seems to contradict prevailing principles for retaining hearing after inner-ear surgical procedures. This finding suggests that hearing preservation is possible after labyrinthine destruction despite the absence of a fluid-filled vestibule and that other mechanisms, such as occlusion of the ductus reuniens with granulation tissue or bone dust, may be sufficient to achieve that outcome.