Motility and intraluminal pressure of the ileocolonic junctional zone and adjacent bowel in a canine model.

The exact role of the ileocecal valve (ICV) at the junction of small and large bowel is not well understood. Bowel segments used for the construction of urinary reservoirs incorporate the ICV. In the Indiana pouch its natural continence is used as one principle for achieving continence of the efferent limb. Motor activity and pressure in the ICV, the ileum and colon were registered in eight dogs. Myogenic activity of the bowel consisted of slow waves, irregular spontaneous contractions and superimposed spikes. Pressures of 7.2 +/- 0.3 cmH2O were recorded in the ileum and of 5.6 +/- 0.4 cmH2O in the colon. The pressure in the ICV was 12.7 +/- 0.4 cmH2O rising to 26.4 +/- 2.2 cmH2O during spontaneous depolarization. Balloon dilatation of the ileum resulted in relaxation of the ICV in 76% of experiments, whereas colonic distension was followed by a pressure increase in the ICV region in 80% of experiments. In 16% of cases a relaxation of the ICV area and a weaker response after repeated dilatation was noted. These findings make the ICV an unreliable continence mechanism as its long-term continence can not be predicted despite intraoperative evaluation. Additional measures to ensure consistent continence at the ICV (e.g. electric stimulation) need to be studied.