Invagination versus simple ligation of the caecal tip with reference to the strength of the caecal closure. An experimental study in the rat.

In an experimental model using the rat, the role of invagination and double invagination for efficient closure of the caecum was studied. A standardized opening of the tip of the caecum was closed in three different ways, thus placing the animals in three groups. I: Closed with simple ligation. II: Closed with simple ligation and a purse-string suture invagination. III: Closed with simple ligation and a purse-string suture and a Z-suture causing double invagination. The caecum was filled with methylene blue and obstructed by a balloon catheter introduced via a caecostomy. Pressure inside the obstructed caecum was measured through a channel opening at the tip of the catheter. The pressure was increased with 4 cm of water every 10 minutes. The maximal pressure reached before leakage of methylene blue from the caecal closure or a drop in pressure in the lumen, was seen to be significantly higher in the groups with invagination and double invagination of the caecal closure, respectively, when compared with those with simple ligation only. The experimental data suggest that the invagination is important for secure closure of the caecal wall.