Perceived straining and incomplete evacuation predict paradoxical contraction of the pelvic floor

Abstract

Patients presenting with chronic constipation often complain of difficult rectal emptying including straining to start a bowel movement, straining to finish a bowel movement and incomplete evacuation. However, the relationship between perceived straining and physiologic dysfunction has not been reported. Subjective straining may also be influenced by psychological status. Aim. This study evaluated the relationship between perceived straining and paradoxical pelvic floor contractions (PC) on anorectal manometry (MANn), electromyography (EMG) and defecography (DEF). The relationship between perceived straining and psychological status was also evaluated. Method. Twenty-six patients (22f/4m;48 -+ 13 yrs) presenting with chronic dyschezia completed an evaluation of pelvic floor function by MANn, EMG, and DEF. All patients also completed a standardized Bowel Symptom Questionnaire and the SCL 90-R. Results. PC was identified in 88.5% of patients presenting with dyschezia. PC was evident on MANn in 23.1% (6/26), on DEF in 23.1% (6/26) and on both in 38.5% (10126). PC was not identified in 15.4% (4/26) patients. Straining and incomplete evacuation did not differentiate the diagnostic PC groups. Classification by defecography was not significantly associated with manometry or EMG, but manometry and EMG were significantly associated (Phi=.54). Manometry revealed significantly higher thresholds for first sensation in the DEF group only. Motor abnormalities included reduced basal anal canal pressure in the patients with PC on both MANn and DEF and increased EAS pressures with straining in the MANn and both groups. The anorectal angle at rest and the change with straining was significantly decreased in the DEF and BOTH. Straining to finish a bowel movement and incomplete evacuation were inversely correlated with anxiety (-,50 & -.48) and depression (-.54 & -.37), but no significant differences were noted between diagnostic groups. Conclusion. Perceived straining and incomplete evacuation were important predictors of paradoxical contraction on manometry and defecography. Concordance between MANn and DEF was low and may reflect important diagnostic differences. Anorectal manometry and defecography are both important tools for differentiating chronically constipated patients with rectal emptying difficulties.