Progression of Contralateral Hearing Loss in Patients with Unilateral Ear Involvement: A Scoping Review

BACKGROUND: Progression of contralateral hearing loss following otologic and neuro-otologic surgeries is a distressing and rare complication. The aim of this study was to systematically review the suspected etiologies and audiological findings in adults who experienced contralateral hearing loss. METHODS: PubMed/MEDLINE, PsycINFO, CINAHL, ISI Web of Science, Cochrane Library, EMBASE, and Scopus databases were searched for this scoping review. The current review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. No limits were placed on language or year of publication. RESULTS: Of a total of 46 studies, 43 studies met the inclusion criteria reporting contralateral hearing loss. The included studies were classified into 3 different categories: contralateral hearing loss after skull base surgeries (n = 21), contralateral hearing loss after middle ear surgeries (n = 17), and contralateral hearing loss after traumatic lesions (n = 5). The cerebrospinal fluid leakage and drill-generated noise were reported as the most reported etiology of contralateral hearing loss following skull base and middle ear surgeries, respectively. The onset of contralateral hearing loss varied from immediately to 18 months after surgery. The severity of contralateral hearing loss varied from a slight to a profound degree of hearing loss. CONCLUSION: Our results highlighted that contralateral hearing loss should be considered following the skull base and middle ear surgeries. Furthermore, this rare complication should be noticed after traumatic lesions.