Enlargement of colonic pouch after proctectomy and colonanal anastomosis

PURPOSE: Although the functional outcome after low anterior resection for rectal cancer using colonic J-pouch reconstruction is superior to that using conventional straight reconstruction, the one drawback of colonic J-pouch reconstruction is difficulty with evacuation. Recently it has been suggested that construction of a larger colonic J-pouch causes the evacuation difficulty. The purpose of this study was to elucidate the cause of evacuation difficulty with colonic J-pouch reconstruction. METHODS: We compared pouchography of 26 patients with 10-cm colonic J-pouch reconstructions (10-J group) and 27 patients with 5-cm colonic J-pouch reconstructions (5-J group) at three months, one year, and two years after surgery. Functional assessments were performed one year postoperatively. Clinical function was evaluated using a questionnaire. Evacuation function was evaluated by the balloon expulsion and saline evacuation tests. RESULTS: The greatest width of the pouch in the 10-J group in the anteroposterior view was significantly greater than that in the 5-J group at all three measurement times (3 months, 4.9vs. 4 cm;P=0.0011; 1 year, 9vs. 5.6 cm;P<0.0001; 2 years, 9.2vs. 5.8 cm;P<0.0001). The value in the 10-J group at one year after surgery was 1.9 times that at three postoperative months; in the 5-J group this ratio was 1.4. There was a significant difference between these ratios (P<0.0001). No significant difference existed between the values at two years and one year after surgery in either the 10-J or the 5-J group. An evacuation difficulty was significantly more common in the 10-J group than the 5-J group. Evacuation function in the 10-J group was significantly inferior to that in the 5-J group. CONCLUSIONS: The evacuation difficulty observed in patients with larger colonic J-pouch reconstructions is associated with excessive distention of the pouch occurring within one year of surgery.