Large contractions in the colonic J-pouch as a possible cause of incomplete evacuation

Restoration of neo-rectal capacity is of importance in obtaining better bowel function after low anterior resection for rectal carcinoma. However, evacuatory disorders, such as incomplete evacuation, have been reported in some patients undergoing colonic J-pouch reconstruction. Therefore, we conducted this study to explore the possible factor affecting incomplete evacuation following low anterior resection for rectal carcinoma.

The subjects were 37 consecutive patients who had undergone low anterior resection for rectal tumor (colonic J-pouch in 13 patients, straight anastomosis in 24). Clinical and physiological outcomes were determined at a mean follow-up time of 12 months after the operation, and the parameters were compared between patients with and without postoperative incomplete evacuation.

Although anastomosis level from the anal verge was lower in the J-pouch group (6.5 cm vs 3.9 cm, P<0.05), there was no significant difference between J-pouch and straight reconstruction regarding clinical and physiological outcomes. Postoperative incomplete evacuation was significantly more frequent in the J-pouch group than in the straight group (46% vs 25%, P<0.05). Postoperative large contractions on ano-rectal manometry were also significantly more apparent in the J-pouch group than in the straight group (31% vs 4%, P<0.05). Presence of postoperative large contractions (P=0.004), anastomotic stricture (P=0.019) and smaller postoperative maximum tolerable volume ( P=0.009) were significantly and independently associated with incomplete evacuation by multivariate analysis.

Colonic J-pouch reconstruction following ultra-low anterior resection was comparable with higher level straight anastomosis from the clinical and physiological point of view. The presence of large contractions might be an important indicator of incomplete evacuation in patients who are undergoing rectal resection.