The isolated bowel segment: angiographic visualization of the developing vascularity

An isolated bowel segment (IBS) is created by a two-stage procedure: (1) initial coaptation of the bowel segment to host organs such as abdominal wall muscle, liver, or intestine; and (2) division of its mesentery several weeks later. Between operations, vascular collaterals develop across the coaptation to preserve viability of the IBS. IBS motility and absorption have been observed in previous studies; this experimental study was designed to angio-graphically observe the vascular collaterals. An IBS was created in four dogs by myoenteropexy between the undersurface of the rectus abdominis muscle and a segment of jejunum or colon. Both IBS ends were exteriorized and intestinal continuity was restored. Four weeks later, the IBS mesentery was divided in three dogs and a sham operation was performed in the fourth. Three weeks thereafter, the animals were killed and appropriate arteries related to the IBS were injected with Microfil radiopaque silicone yellow rubber compound at a pressure of 150 mmHg. After the dye had polymerized, soft tissue X-ray was employed to identify vascular collaterals to the IBS. With ipsilateral deep inferior epigastric artery injection in the dogs with IBS mesentery division, the intramural vessels of the IBS filled via collaterals over the myoenteropexy. Dye injected into the IBS mesenteric artery in the fourth dog outlined the abdominal wall vessels via collaterals that had developed across the myoenteropexy. These observations suggest that the IBS is nourished by the abdominal wall vessels through vascular collaterals that have developed across the myoenteropexy during the interval between the staged procedures, and that viability of the IBS is preserved after IBS mesenteric division.