Essays on Pelvic Pain

WHY INTRAPELVIC BIOFEEDBACK MEASUREMENT IS NOT A RELIABLE INDICATOR OF THE USEFULNESS OF THE STANFORD PROTOCOL AND THE ISSUE OF THE THERAPEUTIC USEFULNESS OF PELVIC FLOOR BIOFEEDBACK

David Wise, PhD

I am responding to a request for a comment about the usefulness of INTRAPELVIC biofeedback measurements in determining if pelvic pain is a tension disorder and appropriate for the Stanford Protocol. My short answer is that electromyographic measurement of the anal sphincter with a biofeedback anal probe, used alone, is an unreliable measure of what is going on inside the pelvic floor. Unremarkable readings of the anal sphincter should not be used to rule out tension disorder prostatitis and pelvic pain nor to dismiss the appropriateness of a treatment of the Stanford protocol.

Here is the longer answer. In my own case, when I was symptomatic, I did an hour or two of pelvic floor biofeedback on a daily basis for a year. After many months of diligent practice, my resting anal sphincter tone was a remarkable zero after about 15 minutes of relaxation. And I was very dismayed to find that I was still in pain at the moment that the anal probe registered zero. I was also disappointed as a clinician experienced in the successful use of biofeedback for other problems. I discovered that the biofeedback measurement seemed to indicate (erroneously) that tension was not a central problem in my pelvic pain.

I did not understand then what I understand now – the electrical activity in the anal sphincter is, for the most part, the only area that the anal biofeedback sensor measures. Often this says very little about what is going on with the other 20 other muscles within the pelvic floor. Furthermore, the biofeedback sensor measures dynamic muscle tension, but not chronically shortened tissue without elevated tone. It is possible to have a relaxed anal sphincter and have pelvic floor trigger points. In this case, elevated tone and active trigger points inside the pelvic floor are not reflected in the anal sphincter measurements.

Shortened contracted tissue inside the pelvic floor, symptom-recreating trigger points when palpated, and a tension-anxiety-pain cycle are the culprits in most people with pelvic pain that we successfully treat (which can sometimes include a chronically tight anal sphincter). We consider these factors criteria for diagnosis. For example, in my experience at Stanford, people with levator ani syndrome almost always have an entirely normal resting anal sphincter tone while palpating the painful trigger points on the levator ani muscle. This is excruciatingly painful. Resolving those trigger points and relaxing the inside of the pelvic floor can resolve this pain without much change in the measurement of the tone of the anal sphincter before or after treatment.

On our website, we have video clips of an important study replicated many times. In it, we demonstrate that at rest, the electrical activity inside a trigger point in the trapezius, monitored by a needle electromyographic electrode, is quite high. At the same time, the electrical activity of the tissue less than an inch away from this elevated electrical activity is essentially electrically silent. If you used a regular biofeedback sensor to measure the general tone of the trapezius, you may well find nothing remarkable. Yet to rely on this information is entirely misleading and would incline you to miss the treatment that could substantially reduce or abate the pain and dysfunction coming from the active trigger point.

The bottom line is that in my experience, electrical measurement of the anal sphincter (or the opening of the vagina) used alone, is often a poor measure of what is going on inside the pelvic floor. While I believe biofeedback is remarkably successful for many other disorders and is one of the treatments of choice for urinary incontinence and vulvar pain, I am unimpressed with the usefulness of biofeedback in treating most male pelvic pain.

The best gauge of the usefulness of the Stanford protocol that treats the pelvic pain of neuromuscular origin is a thorough examination of the pelvic floor for trigger points that recreate symptoms and palpating for tightened and restricted muscles inside the pelvic floor. This must be done by someone with a significant amount of experience and with the kind of myofascial Trigger Point Release that we use. An inexperienced person will miss all this and I have seen many times that even physical therapists who specialize in treating pelvic pain miss trigger points referring the symptoms inside the pelvis. This is one reason why we have offered training for physical therapists who treat male pelvic pain.

We sometimes find it useful when there is a high pelvic floor resting tone because it provides an objective marker that we can compare readings to after the patient has used the Stanford protocol. The idea that pelvic floor biofeedback measurements are a reliable test of whether pelvic pain is a tension disorder represents a misunderstanding of the problem and should not be relied on, especially when the readings are normal. Pelvic floor electromyographic measurement monitoring the anal sphincter is one of those medical tests where a positive finding may mean something and point toward the proper therapy and a negative result doesn’t prove anything.