Abnormal predefecatory colonic motor patterns define constipation in obstructed defecation

Pathophysiology of constipation in the older adult

“…When compared to healthy controls, patients with obstructed defecation demonstrate lower intrarectal pressure and defecation indices and higher anal residual pressures on anorectal manometry recordings during straining ( Figure 1B). Impaired rectal contraction, paradoxical anal contraction, or inadequate anal relaxation seen in patients with obstructed defecation suggests that rectoanal coordination is impaired [58] . The overall frequency of propagating sequences in the colon does not differ between patients with obstructed defecation and healthy controls.…”

Accurate localization of a fall in pH within the ileocecal region: validation using a dual-scintigraphic technique

“…Such classification is justified, as it has the potential to direct medical (29), behavioral (9,10,37), and surgical therapies (26,35). Altered motor activity of the colon can underlie abnormal bowel frequency (17) (and also evacuatory ability) (16) in a significant proportion of chronically constipated patients, and it is now accepted that measurement of colonic transit time (CTT) should be the initial test of choice (13,29). This is presently achieved in clinical practice by two radiological techniques, radioopaque markers and colonic scintigraphy (17).…”

Colonic neuropathological aspects in patients with intractable constipation due to obstructed defecation

“…17 Of practical importance, our results could give an explanation for the lack of response to treatments, especially to biofeedback, in these patients. Biofeedback is to one of the most effective forms of treatment for obstructed defecation 7,20 as also shown by controlled studies, 55 and it is thought that it acts by a learned mechanism of relaxation of pelvic floor muscles.…”

“…Data from radiologic and scintigraphic studies during and after evacuation have shown that the act of defecation can empty a large part of the large bowel, 12,13 and manometric recordings reported that defecation follows a peculiar pattern of propagated high-amplitude colonic contractions 14,15 according to a complex sequence that starts up to 1 h before stools expulsion. 16 Studies carried out by these manometric techniques have then demonstrated that in some patients with obstructed defecation motor abnormalities are also present higher in the colon, in both the basal state 17 and after chemical or mechanical stimulation. 18 Thus, alterations of the neuroenteric circuitry have been postulated as a pathophysiological ground for these patients 17,18 although to date no study has demonstrated such abnormalities.…”

“…16 Studies carried out by these manometric techniques have then demonstrated that in some patients with obstructed defecation motor abnormalities are also present higher in the colon, in both the basal state 17 and after chemical or mechanical stimulation. 18 Thus, alterations of the neuroenteric circuitry have been postulated as a pathophysiological ground for these patients 17,18 although to date no study has demonstrated such abnormalities.…”