Tibial Nerve Stimulation for Urgency Urinary Incontinence
Urologist in Boulder, Colorado
Dr Alexandra Rogers is a urologist by training and has a big passion for helping women with incontinence issues. Over 60% of women suffer from this and over 50% of women have urge urinary incontinence. Yet, roughly 80% are untreated with current therapy modalities. She pursued being part of the eCoin® pivotal trial a unique neuromodulation device and now she is part of their launch for procedural training to physicians to safely implant this device, down in the leg, above the tibial nerve.
How often does Urinary Incontinence occur in female population and what is the impact?
There’s a great update in a paper published in 2022 in the FPMRS journal, where they went back and looked at all the data and found that incontinence is greatly increasing in women. Over 60% of women have some form of incontinence, whether it’s stress incontinence, urge incontinence, or mixed incontinence. So strikingly between pure urge incontinence, where you’re rushing to the bathroom and cannot make it in time, in addition to what we call mixed incontinence, where you have both stress incontinence, which is when you’re on a trampoline jumping and you leak or you have that rushing sensation of “I cannot make it to the bathroom in time”, comes out to over 53% of women, having urge incontinence where they leak.
It’s certainly something that is multifactorial. It’s based on age, so as we age the signal in the nerves that are signalling for the bladder to calm down becomes disrupted. Therefore when women feel the need to go to the restroom do not have the time to make it. A lot of women are suffering from this condition and do not say anything to a professional or certainly in a delayed fashion. They tell a professional, on average 1-3 years later, when they’re really bothered by this. When you do have this type of leakage, it can be incredibly bothersome and really impede quality of life and lead to a lot of social isolation, depression & anxiety. The awareness about therapy options stops at using incontinence products that are expensive and often not covered by insurance. Baby diapers and adult incontinence products are neck and neck for filling landfills, so we have a big problem on our hands from an environmental standpoint. We do not see the prevalence of this condition decreasing by any means when we know that things like obesity and other medical comorbidities like diabetes, which are only increasing, actually make it worse.
Is vaginal delivery associated with urinary incontinence in women?
That’s kind of a misnomer. There are so many women that suffer from overactive bladder that have never delivered or had a vaginal delivery. In stress urinary incontinence where the urethra is slightly incompetent, vaginal deliveries are associated with that type of leakage.
Urge incontinence is a nerve condition. All these women come in and say “I leak and it’s because I didn’t do my Kegels”. Most of the time if you have moderate to severe overactive bladder you can’t “Kegel” your way into staying dry. So physiotherapy for moderate to severe overactive bladder often is not as helpful as we would like. I’m a huge fan of physical therapy for more mild overactive bladder, mild-moderate stress incontinence or pelvic pain conditions, but overactive bladder certainly doesn’t equal “I didn’t do my Kegels”, it’s more of a muscle phenomenon.
How is neuromodulation used to treat overactive bladder?
We’ve been using neuromodulation to mitigate overactive bladder for decades. Sacral neuromodulation was FDA approved in the United States in 1997. That involves a lead being tunnelled precisely along the S3 or S4 sacral nerve. We then create a tunnel to a fatty pocket to put in an IPG to power that stimulation to the sacral nerve. For two and a half decades we’ve been using that form factor of the lead and the battery at the buttocks under sedation or general anaesthetic. This was often done in a multi-phase approach, where we do a testing period anywhere from 2 to 5 weeks, either with a temporary wire or a permanent surgical lead, and test the patient to see if they have at least a 50% improvement in their symptoms, not just in urge incontinence, but also in frequency, in faecal incontinence, in urinary retention, all that nerve misbehaviour that leads to those issues. We have found that if you are good at implanting these leads you have high efficacy with such a therapy and then we proceed to implant the patient with that permanent battery.
This therapy has evolved over the last few years and in 2019 a brand came out with a rechargeable device with the advantage of, by recharge, you could go from a 4-7 year battery life, to up to 15-year battery life. There are two brands that offer that type of therapy, but more recently, just in 2022, both brands came out with a longer-lasting primary cell battery with various external components for the patient to manage, whether it’s a key fob remote or a receiver with a remote with multiple programs. That is a neuromodulation treatment we’ve been offering for decades.
Conversely, peripheral tibial nerve stimulation with a needle, what we call Percutaneous Tibial Nerve Stimulation (PTNS), has been around in the United States with insurance coverage for over 10 years. What we found is that if you place a needle in the office at the tibial nerve and turn up stimulation externally, you see toe flexion and patients feel it along their foot. You do 30-minute sessions once a week for 12 weeks if the patient has a response and typically that drop-off in symptoms or improvement in symptoms happens at week 6 to 12. Then we recommend the patient to do it monthly. So it is a very attractive therapy in regards to there are really no side effects, however, it is burdensome, it is time-consuming, you have to park, you have to check-in, you have to come in and have the needle placed and then you have the 30 minutes of stimulation as it doesn’t necessarily happen immediately. In the United States, there are a lot of insurance barriers where they may view it as experimental, although there are phenomenal papers showing that there’s absolutely an efficacy that’s much greater than placebo/sham. So we’ve had PTNS, but its traction has been variable based on numerous factors.
Finally from a medical standpoint, our last third line that we use is botox injections of the bladder. Women get in a pelvic exam position, we numb the bladder, we take a telescope, put it in the bladder and we do small injections with botox. It is highly effective. Sometimes women are hesitant to sign up for it because they have to redo it every six months. The procedure can be viewed as not exactly modest, there can be discomfort. Lastly, we do have to counsel patients that there is a risk that is so great at relaxing or paralyzing the bladder muscle, just as it will do in faces when we inject it there, that you cannot urinate afterwards. You may have temporary retention and possibly require intermittent catheterizing until the botox wears off. So sometimes that fear factor is tough for patients to digest and often even if they do try this injection they don’t keep follow-up. We see that 90% stop doing it by the fourth visit, so its adherence can be very low.
I’ve just given this breakdown of where neuromodulation is used for overactive bladder beyond medications.
What are the side-effects of the drugs used for overactive bladder treatment?
Anticholinergics were approved in 1975. Oxybutynin or Ditropan are very cheap but have ironic side effects of dry mouth, dry eyes, constipation. All of those things potentiate overactive bladder as patients need more water. Constipation makes overactive bladder worse. So those meds typically are stopped 80% of the time by one year and this is a chronic condition, so the adherence to those meds is terrible. In about 2013 we got our first beta-agonist and it is much safer in regards to side-effect profile. The first one we had, has a warning of increased blood pressure which can be challenging in this older patient population that at least half often already have hypertension baseline and most of those patients are already on 13 meds when they walk in to see you as a clinician.
I do want to bring up one other point about anticholinergics, in 2021 the European Gynecologic Association came out with a clinical statement saying that anticholinergics should not be prescribed to women over 70 due to the mounting association with cognitive risk, i.e. dementia things like that. Therefore, as a clinician, I’m extremely hesitant to offer those medications to patients because I wouldn’t take them myself, having a family history of Alzheimer’s. I always counsel patients of that clinical statement and rightfully most of them say “Well, don’t put me on that” and I agree with them.
We made a little bit more headway where we had a second beta-agonist get approval in the past year. It really has minimal side effects, occasional headaches. However, the issue with beta-agonists is accessibility. They can be very expensive and they often require prior authorization. So in regards to medication share in prescribing, roughly 80% of patients get an anticholinergic and about 20% a beta-agonist and when we look at them staying on it over the long haul most stop by a year, whether it’s due to intolerable side effects, cost or they just don’t work well enough. When you look at med trials you know their efficacy over placebo is not always overly dramatic, so you often give patients a sample and they come back and say “Well, it just didn’t help me enough”.
What's the eCoin® technology and what problems does it solve in tibial nerve stimulation?
Alex: As a clinician, I was incredibly frustrated that we weren’t treating women with the current overactive bladder toolbox, as I call it. I was well-versed in counselling on it, yet I had that high drop off attrition adherence that was poor. So my mentor from medical school, Dr Scott McDermott, was part of the feasibility trial, which was done in New Zealand & the United States and I saw his explanation of the results from that feasibility trial and I’d always believed that that tibial implant had high potential. People talked about it for years but knowing that from an appeal standpoint patients said yes to PTNS or “I’m not scared of that tibial needle. You have a nice staff, so I’ll come in and do it”.
Conversely, I felt very well-trained in sacral neuromodulation which is an art, you have to know how to tunnel that nerve beautifully, you have to surf the nerve, if you’re not on the nerve then you’re not going to get the treatment that you want. It’s kind of challenging to understand. You need to have patients that are willing to undergo kind of a complex multi-phase trial and also have great rep support on the back end to manage nerve fatigue and make sure they understand how to use the remote. So it’s hard to get patients to say yes to sacral neuromodulation and as physicians, we have a three-month wait time for patients coming to see us. When patients walk in the door, you want to hand them this menu, say these are your options, and ask what is appealing and what they will say yes to. I found that it was really challenging for patients driving five hours to see me and especially patients who couldn’t come to 12-weekly sessions, to say yes to sacral neuromodulation. Botox was a middle ground for getting treatment for six months, but they still may say no to that. I already talked about the issues with medications of patients trying or staying on them.
So when I saw this indicator in the feasibility, I was not a big researcher, I was just a normal bread and butter community female urologist, I reached out and I said I need that in my practice, so I became a site for the eCoin® trial. The feasibility trial certainly showed that it works, it had a 60% responder rate meaning that they took patients that came, inclusion-exclusion criteria were very generous, naive surgeons learned briefly how to do this and then they placed it on the tibial nerve. It’s not a surgery, it’s a procedure, it’s a small incision. A pocket is made with a custom tool, so it’s made the same way every time and this coin is dropped in above the nerve. What’s unique about it compared to the form factor we’ve known with a lead and a battery, is that the centre cathode emits stimulation to the outer anode. So the stimulation dome underneath, which lights up the tibial nerve, is very forgiving and the tibial nerve is actually quite big. When I do dissections in the lab, I’m always shocked that it’s like the size of my pinky, so the eCoin® device will hit the nerve. The procedure was designed by an extremity plastic surgeon out of Stanford Super Sen who said “How can I make sure these pelvic floor people get it right every time?”
The dissection is safely done above the fascia. So we do not go below the fascia, I really have no interest in being there personally as a pelvic floor person I do not want to have anything to do with the tibial vein or artery. The stimulation field is at least 6mm and the diameter is about 10mm. So when you think about the size of that nerve, you’re hitting that nerve every time because it’ll take about 4 weeks for that encapsulation pocket to heal. So once it’s encapsulated it’s not going to move while it’s healing. Micro-migrations or migrations up towards the incision doesn’t affect efficacy.
Jonathan: You can place this device above the fascia without going through that and that’s sufficient proximity to actually get good contact or good stimulation with the tibial nerve in the majority of cases I guess, is that right? There’s some anatomical variation, but it’s not a big factor, right?
Alex: No, it’s really this beautiful sweet spot that we’ve always known with PTNS that has these landmarks between the medial malleolus and the Achilles tendon and there’s a custom template marking tool where you use the landmarks to mark out your incision and where that subsequent coin will be in the path of your pocket creation. So it’s a very short learning curve and that’s really exciting because, in my opinion, the learning curve for sacral neuromodulation is never-ending and sometimes with our training you don’t have to learn anything about sacral neuromodulation, so some of us as urologists or gynaecologists go on to do fellowships dedicated just to this work. Essentially, there are not enough of us out there that are extremely well-versed to deliver the art of sacral neuromodulation surgery on a mass scale and manage it, from a remote reprogramming standpoint, even though it absolutely works. For 50% of women that have urge incontinence, we have therapies where only 20% are getting treated. We need constant evolution with these therapies, all of them. We need new tools in the toolbox.
Going back to what the eCoin® device offers, it’s something that I think can be delivered by many, as long as they’re taught how to do it safely and the simulation field is certainly radical from what we’ve ever known with the lead form factor of how to stimulate the nerve. I love the intermittent peripheral stimulation, once you activate it, it goes off every 3 days for 30 minutes and after 8 weeks, every 4 days for 30 minutes. I find that with intermittent peripheral stimulation, you do not get nerve fatigue or habituation. To me, it’s a more stable therapy because a lot of times with sacral neuromodulation I have to reset the patient’s four electrodes because they come in and they lost efficacy where that nerve gets fatigued to that chronic hammer stem.
With eCoin®, I noticed that people stay constant responders and number two what I really love about it, is that it’s automatic, so the patient has nothing to manage. In patients that have a lot of medical issues, they’re older or they may not be tech-savvy, they may have a lot of anxiety, depression when you say “Hey, we’re just going to turn this thing on and you’re done in regards to what you have to do. Versus with Seiko we’ve always had complicated remote end-user things that the patient has to manage, things they need to recharge on multiple levels, whether it’s the IPG or it’s the external device. Those are constantly evolving, we just came out with something that requires nothing to recharge which is really exciting, but I feel this checks some boxes that have not been checked before in regards to a patient coming in and you’re showing them what you have in your toolbox and I think we may get a higher percentage of patients saying “Well, that might work for me”, especially if they live a long-distance away.
What are the side-effects of sacral neuromodulation vs the eCoin® procedure?
I think the risks of sacral neuromodulation at this point are relatively low. However, some of my bigger issues with sacral surgery are not with the sacral surgery per se, it’s the need for a general anaesthetic in an 85-year-old, they need to stop their blood thinners twice, things more of that nature. It’s the same risk of any foreign body implant infection and having to take it out, pain at the generator site, lead migration and having to revise it. I think the danger of tunnelling these things is relatively low if you stop blood thinner from a hematoma standpoint.
The eCoin® device can absolutely be implanted in the office with a local anaesthetic. It was done in the office in 85% of the pivotal patients with just a local anaesthetic. Patients always like a procedure over surgery, if you say you can have surgery or you can have a procedure I found they always say I’ll take the procedure. It just doesn’t sound as scary and that is the truth. That’s only getting worse with Covid, as I went through the two years of Covid and tracked my third-line therapy penetrations, patients wanted more botox & PTNS just because it was in the office or it’s just a procedure. In my opinion, they had a lot more anxiety and depression and it was harder to get into more complicated options no matter what it was I was treating them with, not just incontinence. I think that mindset is only going to get stronger in patients.
The risk with eCoin® is if you put it in, you might get an infection in the leg. The blood flow in the leg is not as good and robust as in the buttocks, so you do have to monitor these incisions very carefully. You have to be smarter about the patient selection from an efficacy standpoint, if they have bad neuropathy in that area well, they are not a good candidate. If they have bad diabetes, are immunocompromised on steroids, have bad blood flow, can’t feel their pedopulses again, not a good patient from not just an efficacy standpoint but from a healing standpoint, they’d be harder for explant. However, if you pick patients that have good leg integrity, the good news is if you were to need an explant, it’s above the fascia, you’re just taking this thing out that’s very superficial you’re not getting into something that is below the fascia. The explant rate in the trial was 3%, which is well within the norm of FDA neuromodulation safety effectiveness data of 4-6%, so they hit that even with a novel therapy, but certainly, patient counselling on this. So the explants that were done were all uneventful and resolved quickly. However, we are learning the whole time how to reduce infection, because no one wants to have to remove an implant from a patient.