[Pelvic floor dyssynergia: videoproctographic analysis and pathologic associations in defecation obstruction...

Pelvic floor dyssynergia is included pathophysiologically in the functional dyschezia group. It is characterized by the paradoxical contraction or lack of relaxation of the puborectal muscle and/or external sphincter during defecation, with consequent functional outlet obstruction. The diagnosis is not always easy because there is no really specific test, nor any diagnostic gold standard; also, many pathophysiologic and epidemiologic findings are still unknown. We tried to define the diagnostic criteria of this condition with the statistical analysis of the main defecographic parameters and to assess the radiologic correlation between functional forms and "mixed" forms, that is those associated with other anorectal disorders.

We reviewed 121 videoproctographic examinations performed January, 1995, to December, 1996, in patients with clinical and instrumental signs suggestive of pelvic floor dyssynergia and compared the findings with those of a control group of 20 patients with no defecation disorders. We also assessed the frequency of the major anorectal disorders associated with pelvic floor dyssynergia relative to the pure form.

Initiation time (11 s versus 1 s; p < .05), evacuation time (47 s versus 10 s; p < .01) and the rate of residual contrast material (57 versus 7) were on average greater in dyssynergia patients. These parameters provide important information on the degree and rapidity of rectal voiding. 81% of our dyssynergia patients had rectal voiding time > 30 s, with final residual contrast material 1/3 to 2/3 of the initial volume. Posterior anorectal angle measurements showed significant differences on strain and evacuation and in anorectal angle excursion at rest/on evacuation (4 +/- 17 degrees; p < .01). Anorectal angle excursion < 15 degrees or its paradoxical reduction was associated with anal diameter < 12 mm during voiding in 85% of cases. We subdivided our population into 4 groups: group A (15 patients: median age: 38 +/- 14 years) with dyssynergia only: group B (22 patients; median age: 54 +/- 23 years) with dyssynergia associated with a functional megarectum); group C (66 patients; median age: 52 +/- 14 years) with mixed pathophysiological patterns such as megarectum, rectocele, intrarectal intussusception, mucosal prolapse and perineal descent; group D (18 patients; median age: 52 +/- 16 years) with the same characteristics as in group C but also with hemorrhoids and anal fissures.

At first (digital radiography) and second level (videoproctography), the diagnosis of pelvic floor dyssynergia is based manly on dynamic parameters (initiation and evacuation times) correlated with the residual contrast agent volume. At baseline, the diagnosis is based on the reduced/no excursion of the anorectal angle between rest and evacuation, together with a narrowed anal eanal. The rate of pure pelvic floor dyssynergia was lower (12.4%) than that of the pathophysiologically mixed patterns and the median age of this group of patients was 38 +/- 14 years, which is statistically lower than that of the other groups (52 +/- 14). Comparing the frequency of purely functional forms in the age range < 40 years, we observed a statistically significant difference (p < .001), which suggests that this disorder is always the first cause of the outlet obstruction syndrome.