Objectives: Colonic motor mechanisms deranged in constipation are not understood completely. Our aim was to measure left colonic motility and tone, during fasting and postprandially in patients with chronic constipation.
Methods: During 1 h fasting and 2 h postprandially, we measured pressures (multilumen manometry) and tone (barostat) in the left colon of 15 healthy controls and 40 patients with chronic constipation associated with slow (n = 15) or normal colonic transit (n = 12) or outlet obstruction (n = 13).
Results: Fasting tone was similar in all groups, and all demonstrated a significant increase in motor activity to food. There was lower postprandial tone (p < 0.05) in the slow transit and outlet obstruction groups. There were no differences in the timing of the tonic response or the number or amplitude of high-pressure propagated contractions. The slow transit group had lower postprandial phasic responses in the rectosigmoid (p < 0.05) and descending (p < 0.1) colon; the outlet obstruction group had lesser descending (p < 0.05) and rectosigmoid (p < 0.1) colon phasic motility.
Conclusions: Colonic intraluminal measurements alone do not discriminate subgroups of chronic constipation more accurately than transit and pelvic floor tests, and currently have a limited role in clinical practice. However, manometry and tone measurements may be helpful in confirming a diagnosis of slow transit constipation (colonic inertia) in patients considered candidates for surgical treatment.