Anatomical basis for the interposition of a gastric pouch between the ileum and the anus after total proctocolectomy.

After a total proctocolectomy, ileoanal continuity is achieved by an ileal pouch-anal anastomosis. This anastomosis is not possible when the ileum cannot reach the anus. To avoid definitive ileostomy in this circumstance, we devised a gastric pouch, taken from the left half of the vertical portion of the stomach, vascularized by the right gastroepiploic pedicle, then interposed it between the ileum and the anus. The aim of this anatomical study on seven cadavers was to estimate the capacity of this gastric pouch to reach the anus. The distance between the caudal edge of the pubic symphysis and the apex of the pouch was measured. It is accepted that an ileal pouch always reaches the anus without tension if it comes down 6 cm below the caudal edge of the pubic symphysis. The apex of the gastric pouch reached a mean of 13.3 cm (range 10-18 cm) below the caudal edge of the pubic symphysis. This technique was then performed on four patients. The apex of the gastric pouch reached a mean of 12.5 cm (range 10-14 cm) below the caudal edge of the pubic symphysis and always reached the anus. These findings emphasize that a gastric pouch interposed between the ileum and the anus after a total proctocolectomy has an excellent capacity to reach the anus without tension.