Functional outcome after restorative proctocolectomy in pigs: comparing a novel transverse ileal pouch to the J-pouch and straight ileoanal anastomosis.

Background: Restorative proctocolectomy followed by an ileoanal J-pouch procedure is the therapy of choice for patients with familial adenomatous polyposis and ulcerative colitis. After low anterior rectal resection, the authors have reported on a novel, less complex pouch configuration, a transverse coloplasty pouch. The aim of the present work was to apply this new design to the ileal pouch construction, to evaluate feasibility, and to measure functional results in comparison with the J-pouch and the straight ileoanal anastomosis using the pig as an animal model.

Methods: Twenty-three pigs underwent restorative proctocolectomy followed by reconstruction with straight ileoanal anastomosis (IAA; n = 5), J-pouch (n = 7), and a transverse ileal pouch (TIP; n = 11). Pigs were followed for 6 days postoperatively. Peristaltic function was assessed by manometry proximal to the pouch, in the reservoir, and at the level of the ileoanal anastomosis. Functional outcome was monitored by semiquantitative assessment of the general condition of the animals, postoperative feeding habits, and stool frequency and consistency. A Fourier analysis was performed in order to compare peristalsis in the ileal reservoirs. The reservoir volume was measured in situ by triple contrast computed tomography scan with 3D reconstruction.

Results: Seventeen animals survived for 1 week. There was no difference in the general condition or the feeding habits of the groups. A significant number of pigs with the TIP pouch (7/10) had semisolid or formed stools as opposed to liquid stools after J-pouch (6/6) and IAA (4/5; p = 0.01). TIP animals had a lower stool frequency (3.2 +/- 1.14 per day) on day 6 after the operation than pigs with J-pouch, 5.33 +/- 1,03, and IAA, 4.6 +/- 1.82 (p = 0.0036). The in situ volume of the pouches did not differ significantly. The Fourier analysis demonstrated a disruption of peristalsis by the J-pouch and the TIP reconstruction but not after IAA.

Conclusion: The function of ileoanal reservoirs after proctocolectomy may result from the disruption of properistaltic waves after pouch formation. The mechanism of peristalsis disruption is independent of the in situ volume of the pouch.