[Histological study on the safety of the controllable ileostomy with pipe]

To investigate the safety of the controllable ileostomy with pipe in view of histology.

Twenty-eight Beagle dogs undergoing controllable ileostomy with pipe were studied. The special fistula tube with balloon was placed into the hole locating at the cecal root opposing the mesenteric side, and fixed by double knot compression method.

The fistula tube was removed 14 days after surgery, then the safety of the procedure was preliminarily evaluated by gastrointestinal radiography and anatomical observation. The small intestine tissue at the compression suture was used as the experimental segment, and the small intestine tissue at the proximal non-compression suture was used as the control segment. The histological staining and the immunohistochemical staining of S-100 protein, c-kit protein and α-smooth muscle actin(α-SMA) protein between two segment were compared, while quantitative comparison of myenteric plexus, intestinal Cajal cell(ICC) and smooth muscle cells in intestinal wall was carried out. After removal of fistula tube at 14 days postoperative, the dogs were normal in feeding and defecation. The digestive tract radiography showed that the intestine was patent without obvious stenosis and obstruction. The dogs were dissected 21 days after operation. The abdominal sinus ostium was well healed and the internal sinus was well formed. Under gross inspection, blood supply, morphology and motor function of experimental intestine segment were similar from the proximal and distal segments of control intestine. S-100 immunohistochemical staining showed that the morphology and distribution of S-100 protein positive cells and "blank area" cells in the experimental and control segments were consistent. Myenteric plexus counting showed that the experimental segment was 3.62±1.82/field and the control segment was 3.27±1.62/field, whose difference was not statistically significant(t=1.30, P=0.20). Immunohistochemical staining of c-kit showed that the distribution of c-kit positive cells in both segments was consistent. Counting of the number of ICCs in myenteric plexus revealed that experimental segment was 2.96±2.57/plexus, and control segment was 2.49±1.80/plexus without significant difference(t=1.81, P=0.07). Immunohistochemical staining of α-SMA showed that the morphology and distribution of smooth muscle cells in whole intestinal wall(muscle layer, longitudinal muscle, ring muscle) in experimental and control segments were consistent. The average absorbance(A) value of α-SMA staining in ring muscle layer was detected and quantified. The experimental segment was 0.15±0.03 and control segment was 0.14±0.04 without significant difference(t=1.16, P=0.25).

The technique of controllable ileostomy with pipe is safe in view of histology, which may replace the traditional protective ileostomy.