Measurements of pelvic floor dyssynergia: which test result matters?

Failure to expel a 60-mL balloon on manometry and abnormal relaxation of anal sphincter on electromyographic testing are frequently used to diagnose pelvic floor dyssynergia. However, the relationship between these 2 test results and their relationship to defecography is poorly characterized. We aimed to describe this relationship and create a predictive model for pelvic floor dyssynergia on defecography.

From March 2008 to April 2010 consecutive patients with symptoms suggestive of functional constipation were evaluated at our Pelvic Floor Disorders Center 125 and the results of their workups were collected prospectively. Sixty-three patients with pelvic floor dyssynergia on defecography were compared with 60 patients without dyssynergia in terms of manometry pressures, electromyographic text results, and balloon expulsion testing results (χ, t tests).

Of 125 patients meeting Rome II symptom criteria for constipation, 123 patients underwent defecography and, of these, 63 (51.2%) had evidence of pelvic floor dyssynergia. Patients with and without dyssynergia had a slight difference in mean resting pressures (62.8 mmHg vs 49.5 mmHg, P = .02) and no discernable differences in rectal sensitivity and compliance: first sensation (56.5 vs 62.5, P = .34) and maximum tolerated volume (164.2 vs 191.2, P = .09). It appeared that abnormalities in electromyographic relaxation and balloon expulsion occurred in the same patients: 84.1% of patients with abnormal electromyographic results also did not expel the balloon. However, the presence of these abnormalities, in isolation or together, did not predict the presence of dyssynergia on defecography.

Normal electromyographic results or the ability to expel a 60-mL balloon does not exclude the presence of pelvic floor dyssynergia on defecography. It is unclear which of these 3 tests should be used to guide the recommendation for (and to then measure response to) biofeedback.