Hydrostatic Characteristics of the Ileocolic Valve and Intussuscepted Nipple Valves: An Animal Model

The ileocolic valve, in the dog, decelerates the passage of stools and prevents fecal reflux. A loss of anterograde resistance worsens the symptoms of short bowel syndrome. The absence of fecal reflux control enhances the risk of recurrence of Crohn's disease. The aim of the present study was to examine what length of intussusception-like nipple valve (INV) should be constructed in order to restore the hydrostatic characteristics of the normal ileocecal valve. The anterograde and retrograde hydrostatic resistances of INVs of different lengths (4, 5, 6, or 7 cm) were compared with those of the normal ileocolic valve by using a contrast enema and x-ray monitoring in a canine model. It was found that the 4-cm-long INV may be sufficient to achieve an appropriate antireflux efficacy (59.60 ± 4.26 cm H2O) versus the ileocolic valve (25.80 ± 4.92 cm H2O), but this does not furnish an anterograde resistance comparable to that of the normal ileocolic valve (10.70 ± 1.15 cm H2O vs. 21.60 ± 3.96 cm H2O). We found that the appropriate length of the INV with which the anterograde resistance of the ileocolic valve could be attained in our model was between 6 and 7 cm. Thus, the shortest possible constructed INV should be effective in clinical conditions such as Crohn's disease, but the recommended length in short bowel syndrome should be greater than this.