The effects of biofeedback on rectal sensation and distal colonic motilityin patients with disorders of rectal evacuation - Evidence of an inhibitory rectocolonic reflex in humans?

OBJECTIVE: Abnormalities of descending colon motility reported in a subset of patients with rectal evacuation disorders are consistent with a rectocol onic inhibitory reflex. Our aims were to evaluate distal colon motor functi on and rectal sensation in such patients and assess effects of biofeedback (BF) training on these functions. METHODS: Seven patients (five women, two men; mean age 36 yr) with rectal e vacuation disorders were studied before and after 10-days biofeedback train ing; six healthy volunteers (five women, one man; mean age 30 yr) were stud ied once. Colonic compliance, motility, sensation thresholds, and perceptio n scores during standardized rectal distentions were measured using two bar ostat-manometry assemblies inserted into the cleansed colon with the aid of flexible sigmoidoscopy. RESULTS: Sigmoid compliance, fasting, and postprandial motility index, and perception thresholds were similar in controls and patients before and afte r biofeedback training. Postprandial sigmoid tone tended (p = 0.09) to be l ower in patients than controls; after biofeedback, postprandial tone was co mparable to that in controls. Rectal urgency scores at 24 mm Hg distention were greater in patients than in controls (p = 0.02 for both). After biofee dback, there were trends for lower perceptions of urgency to defecate (7.6 +/- 1.1 cm pre- vs 5.3 +/- 1.5 post-; p = 0.04) at 24 mm Hg; conversely, ga s sensation at 12 mm Hg was higher (1.2 +/- 0.5 cm pre- vs 3.3 +/- 0.6 post -; p = 0.05). CONCLUSIONS: Normalization of rectal evacuation and postprandial sigmoid to ne in patients with evacuation disorders by biofeedback training supports t he presence of a rectocolonic inhibitory reflex. Effect of biofeedback on r ectal sensation in these patients requires further study. (Am J Gastroenter ol 1999;94:751-756. (C) 1999 by Am. Coll. of Gastroenterology).