Abstract

Introduction and hypothesis: Electrical nerve stimulation is a widely used treatment for overactive bladder but there is no consensus regarding the best placement of electrodes or protocols. We hypothesised that some non-implanted neurostimulation protocols would be more effective compared to others for treating urinary symptoms and improving quality of life among adults diagnosed with non-neurogenic overactive bladder. Methods: A systematic review and meta-analyses of randomized clinical trials were performed in five electronic databases: PubMed/MEDLINE, Lilacs, CINAHL, Web of Science, and PEDro. The main outcome was urinary symptoms—frequency, nocturia, and urgency—and the secondary outcome quality of life. Some protocol characteristics were extracted, e.g., frequency, pulse width, intensity, intervention time, and electrode placement. Results: Nine randomized controlled trials were included. Tibial neurostimulation showed better results than sacral neurostimulation for urge incontinence (mean difference = 1.25 episodes, 95% CI, 0.12–2.38, n = 73). On the pooled analysis, the different neurostimulation protocols—intravaginal, percutaneous tibial, and transcutaneous tibial nerve stimulation—demonstrated similar results for urinary frequency, nocturia, and urgency as well as quality of life. In general, effect sizes from meta-analyses were low to moderate. The best reported parameters for percutaneous tibial nerve stimulation were 20-Hz frequency and 200-μs width, once a week. Conclusions: There was evidence that tibial neurostimulation is more effective than sacral neurostimulation for urge incontinence symptoms among patients with non-neurogenic overactive bladder. Overall, there was no superiority of an electrical nerve stimulation electrode placement and protocol over others considering urinary symptoms and quality of life. Further studies with three-arm trials are necessary. This study was registered at PROSPERO: CRD4201810071.