Inferior reach of ileal reservoir in ileoanal anastomosis. Experimental anatomic and angiographic study.

A possible technical problem encountered when performing ileoanal anastomosis with reservoir is the occurrence of tension when the reservoir is drawn to the anal canal. An anatomic study was performed to assess the gain of caudad reach that can be obtained by dissection of the mesentery root and vascular divisions applied to S- and J-shaped reservoirs, in association with angiographic control of terminal ileum vascularization. The study confirms the clinical experience that caudad reach of ileal reservoirs can be critical in some cases. Complete dissection of the root of the mesentery is a poor lengthening technique, the limiting factor being tension of the superior mesenteric artery. It is simple, however, and should be performed systematically because it can provide 1 or 2 useful centimeters of caudad reach. Division of the ileocecal pedicle is a safe, reproducible, efficient lengthening procedure that can serve all types of reservoirs. In this study, it gave a 5 cm or more gain in caudad reach in 80 percent of the cases, with a slight advantage to the S-shaped reservoir. Distal division of the superior mesenteric pedicle seems more hazardous and can serve only the J-shaped reservoir. For J-shaped reservoirs, maximum caudad reach was achieved when the pouch was built over the most inferior ileal point, which should be checked prior to the procedure, not judged according to predefined measures. The angiographic study showed that, in 38 percent of the cases, cecal vessels participated in vascularization of the last centimeters of the terminal ileum by means of recurrent ileal arteries, which, in 28 percent of the cases, provided exclusive blood supply to this area. Vascularization of the terminal ileum can and should be carefully preserved.