Alan Wein: Hi, I'm Alan Wein from UroToday, and I have the pleasure today of interviewing John Heesakkers, who's one of the true luminaries in functional urology in the world.

John Heesakkers: Now if you then look in the history, what did it look like? This is a stimulator that was implanted in Europe for the first time in 1989. That was done in Nijmegen at that time by Philip Van Kerrebroeck. And if you look at the stimulator well, you can see that it is a neurological pulse generator. It has nothing to do with the lower urinary tract. But this was done in order to start these research sequences in order to have good approval for this implant. That was 1989.

This was the first tibial implant in 2003, the Urgent SQ, as I told you. It is derived from the so-called Brindley device that was done for sacral anterior root stimulation in neurogenic patients, especially spinal cord injury patients. And we changed it a bit, made it a bit smaller, and then we could use it to stimulate the tibial nerve with an implant. And if you look at what results that had in the first small series, that was, well, only eight patients of which six finally could be analyzed. We saw that it was good for incontinence episodes, it was good for voiding frequency, quality of life, et cetera, et cetera. So it had very good effects on the lower urinary tract. This was 2003, and at that time it was not that difficult to do experiments, also not in human beings. That was getting far more complicated afterwards.

So we only did this trial in six patients. We said, "Okay, be happy with your implant and come back if there is trouble." And that was more or less the loose end of this experiment. But we also wanted to know, finally, how were these patients doing years after this implant? Well, that's what we tried to find out 8 years later, and that was published a couple of years ago. We could get to five of these six patients that were still having the implant. There were no issues with the implant. That was very important for us because, for us, the conclusion was at that time that you can have this implant for years at the ankle site, which is a vulnerable site because you can kick it with your feet, you can walk, do something, et cetera, et cetera. But that was not the case at all.

So it appeared to be at least safe. The stimulator didn't work anymore and when it worked, it was not that effective anymore. But we said, okay, perhaps this is something that is having some good effects in clinical practice as well. That was the first attempt, very primitive, long time ago. There are more tibial nerve stimulators that have been tried and have had their moment in practice. This is one of those, this is the Protect PNS. It was called also StimGuard in the past. It is an electrode with four contact points that are very close to the tibial nerve. It is done as a percutaneous procedure. And at this moment there is a multicenter study going on that tries to compare Protect PNS versus InterStim. So that's tibial nerve stimulation implant versus sacral nerve stimulation implant. It should be finalized by now more or less. I don't have new information from this. But finally it should come with some kind of a response to the question, okay, is this tibial nerve implant better than the sacral nerve implant? We have to wait.

Another one is this one from Medtronic. It is a stimulator with a rechargeable battery. It's very small. And it is also put at the tibial nerve outside of the fascia. And at this moment, the study just finished to compare in 188 patients the effect of the stimulator with the stimulator on compared to the ones that had the stimulator off. And then we will also see whether this is good and whether this has additional value to other stimulations that are available at the moment. This one is tested at the moment also, it's called the INTIBIA from Coloplast. It is a stimulator that has a battery in it. It can be changed, but you cannot influence it by yourself as a patient. That was a study done in 208 patients and the study is just finished and we're waiting for the results there. So this is also one that will come up with results soon.

This one is available. This is the eCoin system available in the US, FDA approved for refractory urgency urinary incontinence. It is a battery that is non-chargeable. If it's empty, you have to change it. So you have to take it out, put another in. And that's possible, that was already tested and published. And what we see here is that after two years, this is the latest study from the group, 78% of these patients had more than 50% reduction in their urgency urinary incontinence episodes. Which is a good percentage and which is comparable to, well, mainly all decent trials that have been done on neuromodulation for lower urinary tract disorders, especially for OAB.

Alan Wein: John, what's the lifespan of the eCoin?

John Heesakkers: It was developed to last two years. So that you can have it for two years, then you have to change it. It was also concluded that after the first series that that was too long, so that patients have an empty stimulator even earlier. And then they went to the second generation and they claim that this stimulator can last for about two and a half to three years, and then you have to change it. This one is also the one that is available especially in US because it has FDA approval. It's the Revi from BlueWind. It is a tibial nerve implant without a battery. It is activated from outside with a wearable, as it is called. And with that, you can also control what patients were doing. How long they were stimulating, with which amplitude, how many times a week, et cetera, et cetera.

If you look at the two years result here, and I'm heavily involved in this system, you can see in 155 patients that, in this case 79%, also had more than 50% improvement in reduction of urgency urinary incontinence. So that's comparable to the eCoin. And I think that's the situation that we have now with tibial nerve implants. At this moment, there are implants in development, there are implants available. What we finally want to know is how good are they? How good are they compared to other types of neural modulation? How good are they as compared to sacral nerve stimulation, perhaps pudendal? That will be done in the future, but at the moment we don't know that yet.

So if you want to wrap this up, if you look at the sacral nerve stimulation systems that are there and you want to compare that to another one, there's no comparative trial at the moment. I don't know whether that will come. If you look at sacral nerve stimulation compared to tibial nerve stimulation, there's no comparative trial at the moment. Sacral nerve stimulation versus percutaneous tibial nerve stimulation, so needle stimulation, yes, there is a study done in UK that was done for fecal incontinence and it appeared that the sacral nerve stimulation system was better than PTNS for fecal incontinence. And for the implants, we don't have a comparative trial yet. But the other one, the prototype that tries to compare the tibial implant to the sacral nerve stimulation, will be coming soon hopefully with results. Now as a summary, what can we say at this moment?

What is the situation? I think sacral nerve stimulation at the moment is still the mainstay of neuromodulation. The tibial implants are coming up and they have some advantages, and perhaps we can discuss that later. Because they're smaller, they are at a location that is easier to access than at sacral level in human beings. And that's very important for older people with also, of course, OAB complaints.

It can be done under local anesthesia. It's only one-stage surgery. So it seems quite ideal when the comparison to the other ones is good. And we don't know that much yet about fecal incontinence, non-obstructive retention, and painful bladder syndrome. So perhaps we should go for that too in the future.

Alan Wein: John, thank you so much. And thank you to the audience for listening.

John Heesakkers: You're welcome. Thank you.