Pelvic floor hypertonicity observed in interstitial cystitis/painful bladder syndrome patients

August 1, 2012

For years, some urologists and physical therapists have been saying that the pelvic floor is contracted and shortened because of hypertonicity in patients with interstitial cystitis/painful bladder syndrome (IC/PBS), contributing to their misery. Now, using magnetic resonance imaging measurements, researchers have some physical confirmation that these patients do indeed have a contracted pelvic floor.

Key Points

Elements common to many IC/PBS patients' histories point to the potential role of high-tone pelvic floor dysfunction as a symptom generator. These patients often have other lower urinary tract and pelvic organ dysfunction as well as sexual dysfunction that all could be related to pelvic floor musculature. Frequently, pelvic examination does reveal hypertonicity, including pain on palpation of certain "trigger points." And a controlled, randomized study of pelvic floor myofascial therapy showed that the treatment can ease symptoms in some patients.

Borrowing from MRI measurement techniques used in pelvic organ prolapse, first author A. Lenore Ackerman, MD, and colleagues looked at the records of 15 patients with an IC/PBS diagnosis and MRIs and 15 controls-patients who had MRIs done for fibroids but whose primary symptom was bleeding and not pain. Although not matched one-for-one, the groups were similar in age, parity, age at menarche, gynecologic history, symptom duration, and body-wall adiposity (since body mass index was not usually available).

In axial sections, the radiologists measured the cross-sectional area of the urethra and the width and length of the levator muscles on the right and the left. They also measured the levator angle formed at the posterior margin of the right and left levators. The rationale for that measurement is that, when the pelvic floor tightens, the posterior border of the levators move anteriorly, thus widening the levator angle.

Puborectal distance shorter in IC patients

With most of these measurements, differences between the groups were statistically significant. The H lines, or puborectal distance, were significantly shorter in IC/PBS patients. These patients also had significantly shorter levator lengths than controls. The levator tightening may lift the pelvic floor, resulting in the elevation of the vaginal cuff seen in IC/PBS patients, explained Dr. Ackerman, a urology resident at UCLA working with Larissa Rodriguez, MD, and colleagues. What's more, their levator angle was wider, "consistent with the idea that the posterior border of levator moved anteriorly, widening the levator angle," she pointed out.

The cross-sectional area of the urethra was not significantly different, possibly because of the short urethral length in women. Also, measurements of the M line, an indicator of pelvic organ prolapse, were not significantly different, suggesting "that these findings are due to the changes in pelvic floor and not just to general differences in prolapse between these two groups," said Dr. Ackerman.

Kenneth M. Peters, MD, chair of urology at Oakland University William Beaumont School of Medicine, Royal Oak, MI, wasn't surprised.

"I think this puts into perspective what many of us clinically have come to realize," said Dr. Peters, who was not involved with the study. "I'd argue that in 75% of patients I see in my practice who have been told they have IC, it's neuromuscular, it's pelvic floor. And when you treat the pelvic floor, their bowel, their bladder, their urgency/frequency get better."

But, he added, you don't need an MRI to see the difference, "You just need to do an exam."

That helps point to something that urologists can easily do now in their practices to help direct therapy for their IC/PBS patients-do a pelvic exam in which you palpate the levators for hypertonicity and trigger points. Those patients may derive a great deal of benefit from pelvic floor myofascial therapy.

Whether hypertonicity is the major pain generator in IC/PBS patients rather than some urothelial, immune, or neurologic dysfunction remains to be seen. But if you find it, you can help your patients now.