RESUMEN
PURPOSE: Tinnitus is a common symptom with multiple causes and treatment options. Previous studies have investigated the effect of lidocaine iontophoresis. The aim of this review is to systematically present the effects on tinnitus and to derive possible effects. METHODS: In accordance to the PRISMA statement, the search and analysis were performed. An abstract in German or English and a performed intervention with lidocaine iontophoresis for the treatment of tinnitus, independent of the study design, were considered as inclusion criteria. Due to the heterogeneity of the studies, only a narrative synthesis was performed. RESULTS: The search yielded 179 studies of which 170 were excluded. Six full-texts and three abstracts were included. In total, 957 patients were treated with lidocaine iontophoresis. The percent improvement in symptoms after lidocaine iontophoresis ranged from 4% to 62%. The qualitative assessment of the studies resulted in an overall "weak" rating for all of them. CONCLUSIONS: Due to the heterogeneity and the limited quality of the studies found, no clear statement can be made about the efficacy. The number of those who benefited from therapy varied widely. In addition, it cannot be ruled out that the effect was merely due to electrical stimulation of the cochlea.