Modes of biliobiliary anastomosis in relation to the healing process and occurrence of postoperative stricture.

The inverting and everting methods of biliobiliary anastomoses were compared histopathologically and electron microscopically. Epithelialization started on the 3rd postoperative day and occurred within 8 mm of the anastomosis with an earlier and more active epithelialization being seen in the proximal area than in the distal. A rapid decrease of the mucosal defect was seen for 3-5 days which slowed down thereafter, and closure was achieved by 30 days after the anastomosis in both groups. The everted group showed a smoother and more rapid healing process, quicker epithelialization, and less mucosal defects than the inverted group. In the chronic phase, the inverted group showed more papillary hyperplasia and more pronounced fibrosis of the wall. The stricture index, being the internal circumference of the common bile duct: proximal x 2/anastomosis site + duodenal x 100, of the everted group was 123.7% compared to 146.7% for the inverted group, but there was no statistical difference. There was no difference in the total area of crypts, representing the epithelialization, between the two groups. Anastomoses with proximal dilatation therefore healed more slowly than those without dilatation. These findings show everted anastomosis to be superior to inverted anastomosis and thus support the usefulness of T-tube drainage to prevent postoperative dilatation of the bile duct.