Motility of isolated bowel segment Iowa model III

Abstract

The isolated bowel segment (IBS) is an amesenteric segment of bowel that is devoid of extrinsic nerves and yet is viable with motility and absorption preserved after its mesentery is completely severed. The IBS is created by initial coaptation of a loop of bowel to a host organ, such as muscle (Iowa model I), liver (Iowa model II), or intestine, and secondary severance of its mesentery several weeks later. In previous studies using Iowa models I and II, the viability, motility, and absorption of the IBS were preserved by vascular collaterals, which form across the coaptation. In rats, an IBS was created in the jejunum by initial enteroenteropexy (Iowa model III), followed by its mesenteric division five weeks later. At the second laparotomy, bipolar electrodes were implanted in the IBS and the adjacent jejunum. One week later, myoelectrical recording was performed during a fasting state. Coordinated abroad propagation of migrating motor complex (MMC) was observed in the IBS. The MMC period was 16.9 +/- 1.7 and 19.3 +/- 0.8 min in the intact bowel, and 22.8 +/- 0.8 min in the IBS (P = 0.1). After feeding, the MMC in the IBS was replaced by irregular spike burst activity similar to that observed in the intact bowel. This study concludes that the IBS Iowa model III can be used for studies of bowel physiology.

Autologous Intestinal Reconstruction Surgery in Short Bowel Syndrome: Which, When, and Why

“…A seromuscular incision was made along the antimesenteric border of a jejunal segment, exposing the muscolaris mucosa. Corresponding incisions were made in a host organ: a sero-fascial incision on the undersurface of the abdominal wall in the Iowa model 1 ( 56 , 57 ); an incision on the liver capsule in the Iowa model 2 ( 58 ); a seromuscular incision on a bowel segment in the Iowa model 3 ( 59 ). The deserosed antimesenteric surface of the jejunal segment was then sutured to the host organ.…”

Update on surgical therapies for intestinal failure

“…Review of the published literature reveals numerous case reports and small series describing the outcomes of more than 100 patients who have undergone the LILT worldwide. To overcome these shortcomings of the LILT, Kimura and Soper [52] designed the Iowa, two-step bowel elongation model in which the antimesenteric surface of a dilated bowel segment is attached to host organs such as the abdominal wall or the liver, until vascular collaterals develop across the coaptation from the host organ [53,54]. The case series with lower patient survival were primarily when intestine transplantation was not yet a clinically viable therapy, and, therefore, LILT was applied even in patients with advanced liver disease.…”

The Surgical Approach to Short Bowel Syndrome - Autologous Reconstruction versus Transplantation

“…In the event the bowel mesentery is unavailable for splitting due to adhesions from previous surgeries or when the short gut consists of only the dilated duodenum, the Iowa two-step elongation procedure, another modification, seems more appropriate than LILT [ 66 ]. Here, the bowel is initially connected to a host organ, such as liver [ 66 ], abdominal wall [ 67 ], or adjacent bowel [ 68 ], to allow vessel collaterals to grow into the attached bowel segment, following which the bowel is lengthened with a longitudinal split followed by isoperistaltic anastomosis of the resulting new bowel loops. Since this method requires multiple laparotomies with several weeks of time between surgeries to enable parasitization of the blood supply, it failed to find widespread application.…”