SUFU 2019: Three-Year Followup Results of a Prospective, Multicenter Study with a Wireless Implantable Tibial Nerve Stimulator (RENOVA iStim™ System) in Patients with Overactive Bladder

Miami, FL ( Overactive bladder (OAB) is a highly prevalent condition that can be challenging to treat in patients for whom medical management fails. For those who fail first- or second-line treatment options, neuromodulation offers an alternative treatment option, either in the form of percutaneous tibial nerve stimulation or sacral neuromodulation.

Philip Van Kerrebroeck, MD, PhD, of Maastricht University Medical Center in the Netherlands, presented the three-year follow-up results of a prospective multi-center study regarding a novel implantable tibial neurostimulation device called the BlueWind Medical RENOVA iStim™ System, that is available in Europe.

The RENOVA iStim™ System is a wireless peripheral neurostimulator device that is implanted on the posterior tibial nerve approximately 5cm above the medial malleolus in patients with refractory OAB. The implanted device stimulates the tibial nerve electrically and is wirelessly powered by an external control unit (ECU) that controls the therapeutic parameters. A Clinician Programmer is used to remotely set individual stimulation parameters for each patient (Figure 1), who undergoes treatment at home for 30-60 minutes daily.

In the initial pilot study involving 34 patients with 6-months follow-up, 71% of patients experienced clinical improvement at 6 months following activation of the device. The current study followed 20 of the patients from the pilot study up to 36 months after activation.

At 36 months, in both the per-protocol analysis and in the intent to treat (ITT) analysis, 75% (15/20) of the patients demonstrated clinical success in OAB symptoms, defined as ≥50% reduction in urgent voids or leaks or normalization of voids) compared to baseline. Furthermore, in the per-protocol population, 58% showed >50% reduction in the average number of leaks and 75% showed >50% reduction in the average number of large leaks. In the ITT group, 50% showed >50% reduction in the average number of leaks and 80% showed >50% reduction in the average number of large leaks. These findings mirrored a stable improvement in quality of life parameters, based on the health-related Qualify of Life questionnaire (OABq).

There was only one serious adverse event noted post-procedure, in which a suspected wound infection led to explantation of the device. The authors otherwise reported no long-term surgical revisions due to adverse events or device failures.

The authors, therefore, deemed the BlueWind Medical RENOVA iStim™ System as a stable and effective means to improve storage symptoms and urgency urinary incontinence over time.

Presented By: Philip Van Kerrebroeck, MD, PhD, Maastricht University Medical Center, Maastricht, The Netherlands 

Written by: Judy Choi, MD, Assistant Professor, Department of Urology, University of California, Irvine @judymchoi at the Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction Winter Meeting, SUFU 2019, February 26 - March 2, 2019, Miami, Florida