Function of the Transplanted Small Bowel

Abstract

Introduction: The motility of the transplanted intestine is as important as its absorptive surface to achieve a proper function after transplantation (Tx). The surgeon cannot reconnect the extrinsic nervous system, so that the transplanted intestine depends on its intrinsic innervation only. We want to illustrate this fact and its consequences in the context of intestinal Tx. Case. A 4-year old boy received an isolated intestinal Tx, without colon, for short bowel syndrome due to gastroschisis. The graft was a reduced small bowel from an adult donor. A stoma was created on the distal part of the graft. The surgery was uneventful except for the abdominal closure on a Gore-Tex mesh, subsequently removed on post-Tx days 3 and 5 with control of a normal abdominal pressure. Peristaltism was observed during surgery, however the transit did not establish postoperatively. Multiple biopsies through the stoma showed a normal appearing small bowel. The gastric aspiration was bilious. The child was operated on post-Tx day 11 to look for mechanical obstruction, which was not found. The hypothesis was a motility disorder due to malfunction of the proximal anastomosis between the recipient’s small duodenum and the donor’s far larger jejunum, and possible gastroparesis after long-standing pre-Tx obstruction. Contrast injected through the stoma was found in the stomach. A gastroenterostomy was performed on post-Tx day 25. Biopsies were taken from the upper and lower small bowel. It was thus realized, looking at the villi, mucous cells and submucosa, that the intestine was upside down, with proximal anastomosis on the ileum and distal on the jejunum. The child was re-operated on two days later, to reverse the intestine in anatomical position, and close the distal stoma. The transit established immediately afterwards. Parenteral nutrition was weaned one month later. With 11 years follow-up, the boy is thriving through puberty, with a normal digestive function. Discussion: In this case the small bowel was mistakenly transplanted in reverse position, because the anatomical markers were lost after graft retrieval. Most grafts are either a combined liver and small bowel, or the small bowel and the right colon, conditions where this cannot happen. Expectedly, the motor function could not establish the transit, but the reason for that was not immediately obvious. This rare complication emphasizes the role of intestinal motility in the function of the transplanted small bowel.