Predictive value of the balloon expulsion test for excluding the diagnosis of pelvic floor dyssynergia in constipation

BACKGROUND AND AIMS

The aim of this study was to establish a simple method to exclude the possibility of pelvic floor dyssynergia (PFD) in constipated patients and thus avoid unnecessary expensive physiologic studies.

METHODS

Patients with suspicion of functional constipation (FC) were studied prospectively between 1994 and 2002, excluding those with severe systemic, psychological, or symptomatic anorectal/colonic disorders or taking medications that might modify symptoms or results of studies. Diagnosis of PFD was established retrospectively by manometric plus defecographic findings according to Rome II criteria. Two groups of patients were identified: FC without PFD (FC group) and PFD group. A 30-day symptom diary and balloon expulsion test results were evaluated in all patients. Clinical differences and results of the expulsion test were statistically compared between groups.

RESULTS

Of 359 patients evaluated, 130 were included (FC group, 106; PFD group, 24). According to data from the diary, only anal pain was more frequent in the PFD group compared with the FC group (anal pain in >25% of defecations, 70.8% vs. 40.6%; P < 0.05, chi(2) test). The expulsion test was pathologic in 21 of 24 patients with PFD and 12 of 106 without PFD. The specificity and negative predictive value of the test for excluding PFD were 89% and 97%, respectively.

CONCLUSIONS

The balloon expulsion test is a simple and useful screening procedure to identify constipated patients who do not have PFD. Symptoms are not enough to differentiate between subtypes of constipation.