The superior mesenteric artery. The critical factor in the pouch pull-through procedure.

The critical factor in ileal pouch pull-through operations is the length of the superior mesenteric artery. The pouch must reach the dentate line and have adequate blood supply. A series of cadaver and morgue studies were performed to evaluate the two most popular pouches of the "J" and "S" configurations. The "S" pouch generally reaches 2 to 4 cm more caudad than the "J" pouch. If necessary, however, the "J" pouch can be lengthened 2 to 4 cm by cutting the branch vessel under tension to the pouch, sparing vessels to either side and the marginal arcade. The "S" pouch procedure always sacrifices the ileocecal artery, but the "J" pouch procedure does not necessarily do so. The greatest caudad reach is available when the ileum is cut flush with the cecum. To verify a rule of thumb for reaching the dentate line with the pouch, the length of the superior mesenteric artery (SMA) origin to the inferior margin of the symphysis pubis and the SMA to dentate line were compared. If the tip of the pouch or conduit reached 6 cm below the symphysis pubis, all pouches reached the dentate line.