Small bowel transplantation--harvesting technique and graft preparation in pigs

In more and more frequently occurring short bowel syndrome, requiring total parenteral nutrition therapy, the complications of the latter not seldom prevent its use. The idea of treating these patients with small bowel transplantation pushed the authors to start the program aiming at development of small bowel harvesting, preservation and transplantation technique in experimental settings. Additionally, an attempt to find which, if any, and to what extent, histological changes of the preserved bowel may be of prognostic value for the early transplant failure.

The experiment was carried out on 20 pigs. Two distinct techniques, corresponding to two clinical circumstances in humans, were tested. In the first group of animals, the small bowel was harvested during a model of multivisceral operation, corresponding to the organ harvesting from a brain-dead donor. In the remaining pigs, an isolated segment of the small bowel was explanted, constituting a model of a living related donor surgery. All small bowels were preserved in hypothermia, in Celsior preserving solution for a different, predefined period. During 16 procedures, the harvested small bowel segment was replanted in the same donor, using different vascular anastomotic techniques.

Vascular thrombosis was significantly more frequent in grafts anastomosed by end-to-side technique, as well as in more proximal bowel segments, regardless the anastomotic technique. Following two hours of reimplantation, excised bowel segments did not demonstrate significant differences on histological examination, as compared to the hypothermia-preserved segments (from the same donor) of the same age from primary excision. In most cases, the increase of mucosal damage with preservation time was observed, although statistical significance was reached only for the presence of erosions and necrotic lesions.

On the basis of this experiment one may state, that an ileal graft, assuring the long vascular pedicle (derived from ileocolic vessels) and vascular end-to-end anastomoses are at lesser risk of early vascular thrombosis. While applying the presented technique of purging the graft and its preservation, the act of transplantation itself practically does not influence the histological structure of the bowel, thus is not related to the early graft failure which seems to depend, to the greatest extent, upon the technical aspects of the procedure.