Work-up of the constipated patient

Significance of defecographic parameters in diagnosing pelvic floor dyssynergia

PURPOSE

Defecography is known to be a sensitive and specific measurement of pelvic floor dyssynergia (PFD). However, its standardized parameter for diagnostic analysis is still incomplete. We attempted to determine which defecographic findings are most significant for PFD, and how closely they match other physiologic tests and clinical symptoms of functional pelvic outlet obstruction.

METHODS

Ninety-six patients with constipation who completed work-up of their symptoms with defecography, anorectal manometry and electromyography (EMG) were included in the study. Internal consistency of defecographic findings, and agreements between defecographic findings and results of other tests were statistically analyzed (Crohnbach's α, Cohen's κ, respectively).

RESULTS

Of the 96 patients evaluated, obstructive symptoms of constipation were obvious in 35 (36.5%) by obstructive symptom score. As known defecographic findings for PFD, poor opening of the anal canal was found in 33 (34.4%), persistent posterior angulation of the rectum in 33 (34.4%), and poor emptying of the rectum in 61 (63.5%). Manometric defecation index, manometric evacuation index, and EMG findings compatible with PFD were in 81 (84.4%), 72 (75%), and 73 (76%), respectively. Internal consistency of three defecographic findings was good (α = 0.78). Agreements between each defecographic findings and each result of other tests were all poor.

CONCLUSION

Among known defecographic findings for PFD, one specific finding cannot be considered more important than the others for its diagnosis. It is hard to expect consistent results of various diagnostic tests and to predict the presence of defecographic PFD by use of anorectal manometry, EMG, or even by clinical symptoms.

Measurements of pelvic floor dyssynergia: which test result matters?

PURPOSE

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.

METHODS

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).

RESULTS

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.

CONCLUSION

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.