Refractory Overactive Bladder (OAB) patients have been treated by both Sacral Nerve Stimulation (SNS) and Percutaneous Tibial Nerve Stimulation (PTNS). Although effective, SNS is invasive and laborious, whereas repetitive PTNS is burdensome. The BlueWind RENOVA iStim™ system is a novel miniature, leadless, battery-less, implantable tibial nerve stimulator. The implant is wirelessly powered by a wearable unit that is worn by the patient during home treatment. A clinician programmer is used to set stimulation parameters (Figure 1). A pivotal trial is being conducted to evaluate the safety and efficacy of the RENOVA iStim system for treating refractory OAB patients.
One hundred and fifty (150) women suffering from urgency incontinence will be enrolled in this prospective, single arm, open-label study. The study is being conducted at 23 centers in the United States and Europe. The device is implanted in the lower leg during a minimally invasive procedure in which it is secured superficial to the tibial neurovascular bundle. The implant is activated 4 weeks after implantation. The patient is instructed to apply the wearable unit and perform daily stimulation treatments at home for 30-120 minutes per day. Voiding diary data, quality of life questionnaires and patient satisfaction questionnaires are collected at 6, 12, 24 and 36 months after device activation and are compared to baseline.
To date, 130 patients have been implanted. Baseline mean age 59.6 years, 5.88 UUI/day and 10.07 voids/day. No serious adverse events related to the device or procedure occurred. Two (4%) device and 4 (8%) procedure related adverse events occurred in 50 patients that reached 1-month follow-up. Six and 12 month follow up was reached by respectively 29 and 12 patients.
Previous pilot studies with a BlueWind tibial nerve implant for tibial nerve stimulation in OAB patients showed feasibility of the minimal invasive procedure. To date, the implantation procedure and therapy of the OASIS trial yield a favorable safety profile of the procedure. This technology potentially offers a long-term treatment option without the need for battery changes. The patient-controlled stimulation may also provide stimulation sessions customizable to a patient’s need.