In my last blog, I talked about some of the Physiotherapy treatment options for bladder (or urinary) urgency. Bladder urgency is a sudden, strong need to urinate that cannot be delayed, and it may or may not be associated with urine leakage. It can be a very bothersome problem. We looked at various treatment options for bladder urgency including lifestyle management, other medical management and bladder training. You can go back and read that first blog post on bladder urgency here.
This blog is about another treatment option for bladder urgency called TENS. But before I get to that, I want to quickly mention one other thing I did not include in the last blog about “lifestyle management” for urgency, as pointed out to me by a Physiotherapy colleague: constipation. There is a lot of evidence that constipation - which includes fewer than three bowel motions a week, regular straining and firm, lumpy bowel motions – can make many pelvic health conditions worse. Constipation is strongly linked to bladder urgency and urinary incontinence, with the loaded bowel putting pressure on the bladder and causing irritation. There are, of course, many other factors that may contribute to urgency, and for the sake of brevity I will not go through them all, but constipation is an important one not to miss. So don’t be surprised if your Pelvic Health Physio talks to you about ways to improve your bowels if you go to see them with bladder urgency.
Now back to our main topic this time – the use of TENS for bladder urgency. TENS is an acronym for transcutaneous electrical nerve stimulation. TENS has been around for years, but there is finally good scientific evidence of its efficacy for bladder urgency. It is usually applied via electrodes which stick on the skin and deliver a continuous, low-level electrical current from a small, battery-powered device small enough to fit in a pocket. The TENS unit delivers the current at a frequency designed to target the sensory nerves (nerves that transmit sensations like touch, heat etc), so it rarely causes a muscle contraction. Most people have heard of its use for pain. The same TENS unit that can be used for pain can also be used for bladder urgency, although at quite different settings. However, the way it works is believed to be similar in both cases.
We are not entirely sure, but there are some good theories on how TENS works for different problems. Research is continuing to investigate this further.
It is believed the electrical current from the TENS unit causes something called neuromodulation. In simple terms, this means it changes the messages delivered along certain nerves. In any situation, nerves can be either excited and inhibited from outside and within the body, making these nerves more or less likely to send messages. In the case of both pain and bladder urgency, there is thought to be increased excitation of sensory nerves in affected areas, making the nerves over-sensitive in some situations. The TENS current aims to be directed to those over-sensitive sensory nerves, and has been shown to decrease (or inhibit) their sensitivity, restoring them to a more normal level.
For bladder urgency, we apply TENS at quite a low frequency (10-20Hz) and aim to target the sacral plexus. The sacral plexus is a group of nerves travelling to and from the sacral part (or very lowest part) of the spinal cord, and is where many messages to and from the bladder (and bowel) also converge. This is a simplified explanation, and there are other nerve pathways that are also involved. But this should be enough to understand the basic reasoning behind where and why we apply TENS.
The most obvious place to target the sacral plexus is directly over the sacrum - the triangular shaped bone at the base of the spine. This location works quite well in children and very slim people. However, most adults have a little too much fatty tissue in this area, meaning the nerves we are trying to target are further from the surface, making it harder to get enough current to them with surface electrodes. Therefore, this location is not ideal for everyone.
The other location commonly used for bladder urgency is down on the inside of the ankle and foot, where we can find the tibial nerve quite close to the surface. TENS applied over the tibial nerve is often called TTNS - transcutaneous tibial nerve stimulation. Some people may have heard of a very similar treatment for bladder urgency called PTNS (percutaneous tibial nerve stimulation). Both treatments target the tibial nerve for the same reason, but TTNS uses electrodes that stick on the skin, and can be used at home, whereas PTNS needs to be applied by a doctor in their rooms, as it involves a needle inserted into the leg near the tibial nerve.
This is a question I get from a lot of patients. After all, this seems quite a long way from the bladder. How can an electrical current applied to your foot and ankle influence how your bladder behaves?
The tibial nerve originates from the lower lumbar and sacral nerves in the spine (L4-S3) and has both motor fibres (nerves which cause muscles to contract) and sensory fibres (nerves which transmit sensations). The sensory part of the tibial nerve sends messages back to the sacral plexus, before going further up to the brain. It is believed that it is at the sacral plexus where tibial nerve stimulation can then modulate, or influence, the sensory messages also coming in to the same area from the bladder.
There is now a lot of research evidence to show that tibial nerve stimulation is effective for bladder urgency. Most of the research has been done on some form of tibial nerve sensory stimulation using TTNS or PTNS. It shows that both methods can be equally effective for bladder urgency. There is also some evidence to show TTNS or PTNS may be more effective than certain medications for urgency, or at least enhance the benefits gained from these medications when used in conjunction. The added benefit TTNS may have over PTNS is that it can be applied at home, and is thus cheaper and easier to use, and does not have the sometimes uncomfortable side-effect of needing a needle inserted into the leg.
Interestingly, there is also a small amount of emerging research that motor stimulation of the tibial nerve may also influence bladder urgency. Remember the toe curling or calf stretching ideas I referred to in the last blog which can help some people defer their urgency? This is how this would work. Either way, it seems the tibial nerve can be very useful to influence touchy bladders.
Most people usually come to use TTNS (or tibial nerve TENS) for bladder urgency in consultation with a Pelvic Health Physiotherapist, and I would recommend this. Your Physio can set up the TENS machine with appropriate settings and show you where to apply it (getting this right is important to be effective) so you can self-treat at home. As we discussed in the last blog, they can also guide you on various other ways to manage bladder urgency.
The recommendations in the research as to how often TTNS should be used vary somewhat, but there seems to be evidence that more frequent application gives faster results. I usually recommend my patients start with 30 minutes a day on all or most days of the week for the first 6-12 weeks. You can pop it on while watching the news or reading a book. The majority of the research shows it can take up to 12 weeks to see a result, as neuromodulation can take time. However, anecdotally, I have many patients who have reported significant changes within the first 6 weeks. Most people will usually loan a TENS unit from me for this initial trial. But if this proves helpful, it is often more cost effective to buy your own unit if longer-term use is needed. They can be obtained for around $50-$70 online. The simpler, cheaper units that can be manually set are often the best.
In terms of ongoing use, it can be a bit of trial and error. The research seems to show most people need some sort of “top-up” treatments with TENS after the initial 12 week treatment period. If you have your own TENS unit at home, this is easily done. I find the majority of my patients do best by gradually weaning off their TENS use, with occasional top-ups as needed.
In conclusion, there are many ways we can manage bladder urgency with conservative measures, and they do not just involve medication. Your Pelvic Health Physio can guide you on most of these methods, but your GP will need to help when it comes to medication. If you feel bladder urgency may be a problem for you, I would highly recommend talking to your GP or contacting a Pelvic Health Physio for some help.
Yours in good health.