Long-term function of experimental substitutes of the ileocecal valve

The bacteriological barrier function of the ileocecal valve (ICV) can be replaced according to the principle of the nipple-valve anastomosis. Since late complications due to technical measures for stabilizing the ileal nipple have been hitherto unknown, 12 adult beagle dogs were operated on by three technical modifications of a nipple-valve anastomosis and were followed up for 1 year: In three cases the ileal nipple was stabilized by longitudinal staples (NVA), in three cases an intestinal neosphincter (INS) was produced by healing of the muscular layers between the ileal nipple and colon, and in six cases an oral zone of stabilization, preserving an aboral valve zone (S-NVA) was constructed. Measures for valve function at the end of the study period were the weight course of the animals and the intestinal bacterial profile, considering morphological complications of the substituted valves. As reference the respective bacterial counts in ICV and end-to-end anastomosis (EEA) were used, which had been determined in the same animals in earlier experiments. Following an initial increase in weight the 3 animals with NVA and the three animals with INS continuously lost weight from the 4th postoperative month onward. The 6 animals with S-NVA, however, showed from the 4th postoperative month onward a significantly higher weight level (p < 0.05), which remained constant up to the end of the 1-year observation period. Because of a morphologically intact structure of the substituted valve a significantly (p < 0.05) better bacteriological clearance of the ileum was confirmed in these animals after 12 months when compared with the EEA group. In contrast, in the NVA and INS animals a severe bacterial overgrowth of the entire small intestine was observed. This was caused by an intestinal stagnation due to partial prolapse of the nipple in NVA and due to fibrotic stenosis in INS. The results of our study suggest that technical measures to relieve the tendency to devaginate are only successful, if they do not lead to obstruction of the orthograde intestinal passage in the long term. Thus, only the clinical introduction of the S-NVA model may be justified.