Intestinal anastomosis in the rat facilitated by a rapidly digested internal splint and indigestible but absorbable sutures

Murine ileocolic bowel resection with primary anastomosis

Intestinal resections are frequently required for treatment of diseases involving the gastrointestinal tract, with Crohn's disease and colon cancer being two common examples. Despite the frequency of these procedures, a significant knowledge gap remains in describing the inherent effects of intestinal resection on host physiology and disease pathophysiology. This article provides detailed instructions for an ileocolic resection with primary end-to-end anastomosis in mice, as well as essential aspects of peri-operative care to maximize post-operative success. When followed closely, this procedure yields a 95% long-term survival rate, no failure to thrive, and minimizes post-operative complications of bowel obstruction and anastomotic leak. The technical challenges of performing the procedure in mice are a barrier to its wide spread use in research. The skills described in this article can be acquired without previous surgical experience. Once mastered, the murine ileocolic resection procedure will provide a reproducible tool for studying the effects of intestinal resection in models of human disease.

Study of morbidity in orthotopic small intestine transplantation with Wistar rats. Experimental study

BACKGROUND

Transplantation of the small intestine is a surgical procedure currently under investigation for its possible application in the treatment of patients with short bowel syndrome, aiming at the reintroduction of an oral diet.

AIM

To define the morbidity and mortality of intestinal transplantation in small animals using microsurgery. Intra and postoperative morbidity and mortality were studied in Wistar rats submitted to orthotopic intestinal allotransplantation.

MATERIAL AND METHOD

The animals were divided into three groups: group A (37 donor animals), group B (37 recipient animals), and group C (10 control animals). Group B was divided into three subgroups according to survival time. Subgroup TI consisted of animals that died during surgery or due to causes directly related to surgical intervention, subgroup T2 consisted of animals that died between the 4th and 29th postoperative day, and subgroup T3 consisted of animals that survived after 30 days. Transplanted animals were evaluated in terms of surgical technique used (vascular and intestinal anastomosis), graft quality, surgical time, and clinical parameters. The animals that died by the 29th postoperative day were submitted to autopsy and the remaining ones were sacrificed after 30 days.

RESULT

There was a high rate of complication of a surgical nature. Early mortality rate, i.e., mortality up to the third postoperative day, was 54% with vascular anastomosis being the major cause of death. Surgical time was evaluated in a restricted and homogeneous group and showed a strong prognostic value in terms of successful transplantation. Clinical parameters such as weight loss, reduction of ingestion, reduction of motor activity and diarrhea were directly correlated with acute rejection.

CONCLUSION

The experimented intestinal transplant is a procedure companied by considerable morbidity and mortality due to surgical complications in postoperative period, vascular anastomosis and total surgical time.

Warm ischaemia time in a model for small bowel transplantation

Intestinal transplantation is associated with high rates of mortality and morbidity. This paper details our initial experience with 82 heterotopic small bowel transplants based upon the original rat model described by Monchik and Russell (Surgery 70:693-702, 1971). A key issue associated with mortality was a warm ischaemia time of more than 40 min (P < 0.01). Sixty-eight percent of the recipients (44/65) survived for more than 24 hr when the warm ischaemia time of the donor bowel was reduced to less than 40 min. Investigators establishing an animal model of heterotopic small bowel transplantation should pay particular attention to the warm ischaemia time of the donor bowel.

Refined technique for intestinal transplantation in the rat

Unlike other solid organ transplants, intestinal transplantation (IT) remains a highly experimental procedure. Rejection, sepsis, and graft-versus-host disease have been the major barriers to successful IT in humans. These problems can be studied in the rat model, but this requires a reliable surgical technique that will produce high survival rates and excellent graft function. Herein, we review 400 consecutive IT in rats and describe important technical aspects of surgery. Technical modifications that have helped to reduce the morbidity after IT in rats include 1) minimizing mechanical and ischemic injuries to grafts during the donor procedure, 2) marking the portal vein and aortic conduit with sutures to ensure correct orientation of the graft, 3) using a macaroni noodle to stent the intestinal anastomosis, and 4) administering large volumes of crystalloid to maintain a normal blood pressure during the donor and recipient surgeries. The survival rate in 298 rats with accessory, heterotopic grafts was 90%. The survival rate in 102 rats with orthotopic (in continuity) graft (OIT) was 86%. Rats have survived more than 500 days after OIT, maintaining normal weights, intestinal function, and intestinal histology.