For women who have unsuccessfully tried to manage their overactive bladder (OAB) with medication, another option may be neuromodulation, or nerve stimulation treatments. Dr. Jonathan Shepherd is a women’s health and OAB expert at the Magee Women’s Hospital of University of Pittsburgh Medical Center (UPMC).
Recently, he answered questions about his experience with Interstim (surgical) and PTNS (non-surgical) neuromodulation treatments for OAB.
What exactly is nerve stimulation treatment, and how does it help with OAB?
There are two main types of neuromodulation for OAB, Interstim sacral neuromodulation and posterior tibial nerve stimulation (PTNS). These therapies send an electrical stimulation to nerves associated with the bladder. Interstim stimulates these nerves at the exit from the tailbone, or sacrum, and PTNS stimulates the most distal part of these nerves behind the ankle.
They reduce how frequently women have to go to the bathroom, and help delay or eliminate the sudden urge to empty the bladder, which is sometimes caused by spasms of the bladder muscle and can be associated with leakage of urine.
How does it work?
**Interstim **uses a device much like a pacemaker, which is implanted. An electrical wire called a lead goes from the device over to the tailbone, and stimulates the nerves there. This device is implanted through surgery and can be controlled with a separate wireless controller. PTNS, by contrast, is based on an ancient acupuncture point thought to help control the bladder. Small acupuncture needles are inserted behind the ankle, and a small electrical current flows through the needle, stimulating the nerve. The needle is removed in between sessions, and a new one is replaced at the next visit.
Which OAB patients would most benefit from nerve stimulation?
Neuromodulation is a good option for people who have not successfully been able to manage their overactive bladder with medications and behavioral changes. It does not work for all people, but a large percentage will have success after an evaluation by a specialist to rule out other conditions. There is a small subset of women usually with other conditions who need to have MRIs performed frequently, and Interstim is not appropriate for this group.
I understand that the nerve stimulators are sent near the feet or ankles. Why send stimulation there if the problem is in the bladder?
Neuromodulation can be either performed at the level of the tailbone near the nerve roots with Interstim, or further down near the ankle with PTNS. When PTNS is performed at the ankle, the electrical signal is carried up to the brain at the same location where signals from the bladder are received. We are trying to better understand this effect with ongoing research, but even if we do not fully understand the way it works, we cannot deny the benefits we have seen in patients.
How long do these treatments take, and how long does it take to see results?
PTNS requires 12 weekly sessions, usually followed by monthly maintenance sessions. Results can be seen immediately, but some women may require all 12 visits to see an effect. On average, it takes six weeks. With Interstim, the device is implanted in the operating room, and women will generally see an effect immediately. It may require fewer maintenance office visits after implantation.
Are either of these procedures painful?
With Interstim, the procedure is performed on an outpatient basis, and women go home the same day. They are given a prescription for pain medications, but most find these are generally not required. PTNS is performed in the office, and there may be a tingling sensation during the 30-minute session, but after the needle is removed there is generally no pain. There may be some short-term redness where the needle was inserted.
What kind of results can a patient expect to see?
Results may vary with both procedures. Results can range from complete continence and normal intervals between trips to the bathroom, to no effect at all. But, overall, there is a 60 to 70 percent success rate. This may sound low, but it is actually a good success, given that neuromodulation is performed only in women who have already failed other treatment options.
Are there any risks, complications or side effects associated with neuromodulation treatments?
**PTNS **has fewer risks. Irritation at the site and slight discomfort during the stimulation period are the biggest risks. This is balanced, though, by having to come in for multiple visits. Interstim is an implanted device, so there is the risk of infection, which could result in having to have the device removed. This happens about 5 percent of the time. Sometimes, there also is the need for a second surgery to adjust the stimulating wire lead if it malfunctions.
When should a patient begin discussing this treatment with her doctor/urologist?
Once two medications have been tried and there is no evidence that pursuing more medications will be successful. At this point, it is reasonable to consider neuromodulation.
How long have these procedures been available?
Interstim was approved by the FDA in 1997. PTNS was approved in its current form in 2005, but a similar device that was a precursor to the current treatment was approved in 2000.
What is your experience with the response to neuromodulation treatment for OAB?
My experience is much more limited with PTNS, as we have just started regularly offering this in our office in the last couple of months. However, I have had excellent results with Interstim. In fact, some of my patients who were the most difficult to treat before this intervention have had some of the best responses. Once again, it’s not 100 percent, but I have really seen life-changing results in some patients.
Is neuromodulation something that has to be continued long-term in order to see lasting results?
With Interstim, the device will be implanted for a long time. After an average of four to five years, the IPG will need to be replaced. This is the piece that contains the battery and electronics to program the stimulation. For PTNS, the majority of people will have to go on a maintenance protocol to maintain the results that are seen with initial therapy. This generally involves a monthly treatment in the office with the device.
Is nerve stimulation treatment covered under insurance plans? If not, how much would this treatment cost?
Most insurance plans cover neuromodulation. I have not had issues with coverage for Interstim. Since PTNS is a newer treatment option, we were originally having some insurance coverage issues, but now I find that most plans will cover at least the initial treatment. However, they may not cover maintenance therapy.