Tibial Nerve Stimulation for Urge Urinary Incontinence and Overactive Bladder: Narrative Review of Randomized Controlled Trials and Applicability to Implantable Devices.

The tibial nerve is an established target for neuromodulation in the management of overactive bladder (OAB) and its associated symptoms, including urge urinary incontinence (UUI). Technologies are currently available to deliver tibial nerve stimulation (TNS) through percutaneous devices or through implantable devices. The benefits and safety of percutaneous TNS have led to it as a guideline-recommended therapy. However, patient compliance is limited by the burden of weekly office visits and the need for maintenance treatments. Further, insurance often only covers a limited number of lifetime visits for percutaneous TNS. These factors and others have led to the development, study, and utilization of implantable TNS devices. Implantable TNS devices deliver the same therapeutic mechanism of action for nerve stimulation with a permanent implanted device that provides at-home stimulation rather than in-office therapy delivery. Additionally, there is an added potential for dynamic and patient-centered stimulation. There is a large body of high-quality evidence published for TNS, including numerous randomized controlled trials published on percutaneous TNS which have consistently demonstrated superior efficacy to sham and similar efficacy to that of anticholinergic medications. Percutaneous TNS also performs better than conservative therapy including pelvic floor muscle training. The percutaneous and implantable approaches deliver nerve stimulation to the same target nerve, using the same mechanism of action. Therefore, data from randomized trials of percutaneous TNS are informative for implantable TNS devices. At the time of this article's publication, at least two implantable TNS devices have received marketing authorization from the Food and Drug Administration (FDA). The objective of this review is to discuss the mechanism of action for TNS and summarize the published literature from clinical trials of percutaneous TNS as a foundation of high-quality evidence for implantable devices targeting the tibial nerve.