Dr. Sutherland on current options in tibial nerve stimulation

In this video, Suzette E. Sutherland, MD, MS, FPMRS, discusses the 2 FDA-approved options for tibial nerve stimulation, which were highlighted during a session at the Society of Urodynamics, Female Pelvic Medicine, and Urogenital Reconstruction 2024 Winter Meeting titled, “What’s available in Tibial Nerve Stimulation and What’s Coming.” Sutherland is an associate professor in the department of urology and the director of female urology at the University of Washington Medical Center in Seattle.

Video Transcript:

Currently, in the area of tibial nerve stimulation, there are only 2 FDA approved options. One is called eCoin, by company called Valencia, and the other is Revi, by a company called BlueWind. There are differences between these 2 therapies. They inherently do relatively the same thing by providing stimulation to the posterior tibial nerve with the hopes that it will help the patient's symptoms for overactive bladder and urge incontinence. When we look at these 2 types of therapy, there are differences and some significant differences from a surgical standpoint as well as when we look at the FDA approval trials, what the outcomes of those trials were. They both are very viable options.

The eCoin is the one that came out first, FDA approved in 2022. It's about the size of a nickel. It is the lead and the generator with a battery, all in one. It slides just in the subcutaneous tissue over the fascia that's overlying the posterior tibial neurovascular bundle through a simple incision, so it can be done very easily under a little bit of local in the office. The FDA approval trial was set up such that the device went off on its own, for I believe it was about a 30-minute session, maybe it was an hour, every 3 days for the first 18 weeks, and then it was every 4 days thereafter. So, it wasn't every day. When you look at the results of that, it showed that there was a 70% responder rate. Now again, in the world of neuromodulation, what does responder rate mean? It means that the patients get equal to or greater than 50% improvement in their symptoms. That's the bar. Any device in the area of neuromodulation has to meet that bar. That means the patients got at least 50% improvement in their symptoms, and hopefully some, a little bit more. These also were patients who were pretty wet; they had 4.2 urge incontinence episodes a day. If you think about that, they are, every day, having several wetting episodes. That doesn't say anything about the degree of the wetting, but they're actually having several wetting episodes a day. To improving that by 50%, that can change your quality of life. The other thing with the eCoin is that they did have a dry rate looking at 3 days in a row on the bladder diary where the patient was dry and didn't report any incontinence over a 3-day period, that's what they call their dry rate. Their dry rate was 20% to 25%. So, about a fourth of the patients were actually dry.

When we look at the Revi system for BlueWind, its design is a bit different. First of all, again, it can be done in the office. For the FDA approval trial, they were all done in an outpatient surgery center just to have more control over it, but the idea is that hopefully at one point, they'll be done on an outpatient basis, maybe in an office just under local. In full disclosure, I was on this FDA approval trial, so I do know a little bit more about the details of it. The difference here is that the lead is the only thing that's implanted, not the generator or the battery, just the small lead. The other big difference is that an incision is made in the fascia and the lead is placed under the fascia directly on the posterior tibial nerve neurovascular bundle. That stimulation is going directly on that neurovascular bundle. During the implantation, there is some testing that's being done, so that you can also test and see where the patient is feeling it. Are they feeling it in the right places on the foot, so on and so forth. There's actually some testing being done to know you're in the right spot. For the eCoin, there's no testing; it's just placed above the fascia. The other big difference in the FDA approval trial with the Revi device is that the patients were stimulated every day, not every 3 to 4 days, but every day. They wear, I call it an ankle bracelet. To be truthful, it looks a little bit like the patient is on parole. This is a first-generation ankle bracelet, so more refined ones hopefully will be coming down the pike. In any case, that's what stimulates the lead on the inside, and that's where the battery is. There's no longer any need to do subsequent surgeries to change batteries because all of that is external. The patient wears that wearable and stimulates the lead, for the FDA approval trial it was 30 minutes twice a day. But it was daily. They can be up walking around with it while it is stimulating, they're not forced to be sedentary. With that therapy, the FDA approval data showed that there was an 82% responder rate, not just a 70%, like with the eCoin, but an 82% responder rate. Again, meaning that patients were at least 50% improvement is what they saw. When you looked more closely at that data, we also saw that there was almost a 70% rate of patients with greater than 75% improvement, so not just 50%. They hit the bar, and then some, went well over the bar. That's the point there. The other aspect is that we looked at the dry rate, again, as defined as no incontinence over a 3-day period in a row; it was 50%.

The comparisons here with the eCoin is a direct responder rate, meaning the 50% cut off bar, of 70% and a 20% to 25% dry rate, vs with the Revi system, it was an 82% responder rate, with over 70% of those patients getting over 75%, so having really good results, and a 50% dry rate. Now there are big differences between these 2, in the sense that one is a system that is sitting above the fascia, and the other is opening the fascia and placing it directly on the neurovascular bundle. Is that why there's a difference in what was seen in the data? We don't know. The other thing would be that eCoin was designed to just stimulate every 3 to 4 days, whereas Revi stimmed every day. If we were able to do a head-to-head trial and have them both stimming every day, what would we see? We don't know. As we get more experience with these devices now that they're both FDA approved, more people will hopefully be utilizing them, and hopefully we'll see as more time goes on. The most likely scenario is that there's a role for each of them, looking at different patient preferences and such.

This transcription has been edited for clarity.