Rechargeable neuromodulation system found safe, effective

One year after implantation, a miniaturized, rechargeable sacral neuromodulation system remains a safe and effective treatment for overactive bladder, according to results of a European post-marketing clinical follow-up study presented at the International Continence Society annual meeting in Philadelphia.

Among patients with a clinical response 1 month after implantation, most went on to have clinically and statistically significant reductions in overactive bladder symptoms at 1 year, according to investigator Bertil F.M. Blok, MD, PhD, of the department of urology at Erasmus Medical Center, Rotterdam, The Netherlands.

“This rechargeable sacral neuromodulation system may provide significant cost saving, and reduction in patient risk and physician burden, by eliminating frequent replacement surgeries,” Dr. Blok said in a podium presentation to ICS attendees.

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That’s because patients implanted with a non-rechargeable sacral neuromodulation system could require multiple replacement surgeries over a lifetime, resulting in increased expense and surgical risk, Dr. Blok and colleagues said in the presentation’s abstract.

This prospective study, known as RELAX-OAB, included 38 female and 13 male participants (mean age, 51 years), of whom 73% had overactive bladder with urgency urinary incontinence. All subjects were implanted with the rechargeable sacral neuromodulation system (r-SNM; Axonics) at one of seven European centers. Each patient had a single procedure to implant the device, which consists of a tined lead and an implantable pulse generator. The device is not available in the United States.

After a 1-month test period, 71% of patients were judged to be “test responders,” as shown by a reduction of 50% or greater in voids, a reduction of 50% or greater in incontinence episodes, or fewer than eight voids per day.

One year after device implantation, 94% of those test responders continued to have a response, according to Dr. Blok.

For the main outcome of urgency urinary incontinence, 96% were responders, bladder diary entries showed.

“Of those, 42% had more than 90% improvement, and in total, 23% of the patients were dry,” Dr. Blok said.

Next:91% of patients satisfied with deviceThe number of voids per day went from an average of 14.3 at baseline to 8.0 at 1 year, and similarly, the number of leaks per day went from an average of 8.3 to 1.8 over that same time period, according to Dr. Blok. Quality of life also significantly improved at 1 year, and 91% of subjects said they were satisfied with the device, the investigator said.

Recharging was easy, according to 91% of subjects. One hundred percent said the duration and frequency of recharging was acceptable; 70% recharged every 2 weeks, on average, while 30% recharged every week.

Serious adverse device events were not seen in the study, Dr. Blok said, although 10 subjects had undesirable stimulation that resolved with reprogramming, and one patient had pain at the implantable pulse generator site that resolved with reprogramming.

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One patient had a lead migration, and three subjects were explanted due to an infection related to the procedure or lack of efficacy, Dr. Blok added.

In terms of procedural complexity, implantation of the lead is “exactly the same” compared to the non-rechargeable sacral neuromodulation device, Dr. Blok said.

Implantation of the battery is simpler, according to Dr. Blok.

“You place the battery lateral from the incision, and you only have to make a pocket with one finger, and then that's enough,” he said.

Dr. Blok reported a financial disclosure related to Axonics Modulation Technologies, and noted that the company provided funding for him to attend the ICS meeting.