Diverticular rupture during colonoscopy. Fact or fancy?

Uncomplicated colonic diverticula have been regarded as weak points in the bowel wall which have a predisposition to rupture during colonoscopy. We attempted to prove or disprove this assumption. Eleven segments of diverticula-containing sigmoid colon were insufflated via a colonoscope and the rupture pressure manometrically recorded. The mean +/- SEM pressure causing serosal tear was 202 +/- 15 mm Hg and mucosal rupture 226 +/- 14 mm Hg. No diverticular blowouts occurred. Intraluminal sigmoid pressures were measured manometrically in 15 patients with and 15 patients without colonic diverticula during routine colonoscopy. The pressure recordings were read in a blinded fashion, and the values were then grouped and analyzed in those patients with and without sigmoid colon diverticula. Intrarectal, sigmoid, peak sigmoid, peak sigmoid with cough, and peak sigmoid with Valsalva pressures were similar in both groups. Furthermore, the pressure levels generated during colonoscopy were much lower than those required for colonic rupture in the cadaver colons. We conclude that the reason most colonic perforations occur in the sigmoid area is not due to diverticular blowout. Rather, excluding instances where electrocautery is used, we feel it is due to instrument trauma. Less commonly, excessive air insufflation can result in serosal laceration and mucosal rupture, whereas diverticular blowout is probably limited to the setting of acute diverticulitis.