Assessment of an implantable ileostomy sphincter

A totally implanted, intermittently inflatable, silicone rubber cuff, reservoir, and control mechanism were evaluated for use as an artificial sphincter in 18 female beagle dogs that had undergone ileostomy. The dogs were divided into daily 8-hour occlusion, test, and always open, control, groups. Animals were evaluated daily for continence and peristomal irritation. Quantitative aerobic and anaerobic cultures, measurements of ileal accommodation, net fluxes of H2O, Na, K, and taurocholate, fecal fat loss, and urinary excretion of oral 58Co X B12 plus mucosal suction biopsies were done at 4, 12, 24, and 36 weeks. Eight hours of daily occlusion caused dependable continence without causing damage to the underlying or upstream mucosa and significantly reduced the incidence of peristomal erosion (6.8 +/- 0.8 days/dog-days X 100 versus 50.7 +/- 7 days/dog-days X 100 [+/- SEM] [p less than 0.001]). Occlusion also promoted anaerobic bacterial growth (9.00 +/- 0.41 logs versus 6.70 +/- 0.58 logs [p less than 0.001]). Test animals showed significant capacitance accommodation of the terminal ileum without incurring defects in ileal absorptive or secretory function. Gangrenous herniation of small bowel through an aperture formed by an intestinal loop adhering to the capsule surrounding the cuff, device failure, and fibrotic obstruction occurred sporadically as late as 29 weeks after implantation. The artifical sphincter was effective and was physiologically well tolerated, but its specific liabilities require further address.