An Experimental Study On Replacing The Long-Segment Defects Of Ureter By Tailoring The Pedicle Ileum

Objectives: To research ideal replacement material for ureter defect. We establish experimental rabbit model of tailoring the pedicle ileum substitution for long-segment ureteral defects using the Yang-Monti principle with microsurgery anastomosis. To evaluate merits and disadvantages of this operation for clinical application based on animal experiment.Methods: A total of 24 rabbits were randomly divided into experiment and control group, mean weight 2.5kg～3.0kg. The experiment group was operated ureter substitution and contralateral nephrectomy, then we detected the pathology of ureter and isolateral kidney and observed the morphologic change with H.E. dyeing after killing them at 1W (n=2),2W (n=2),4W (n=2),6W (n=2),12W (n=4), respectively. Intravenous urography and B ultrasound was performed in experimental group in 2W (n=2) and 12W (n=4) to evaluate renal function, and retrograde pyelography was performed after harvest to identify ureteral stricture or obstruction. The ureteral grafts were measured and examined histologically. And we determined serum creatinine, urea nitrogen and electrolytes before the animal were killed. The control group was determined serum creatinine, urea nitrogen and electrolytes before killed. If rabbits were dead, we selected the rabbits at the same situation to supplement.Results: One of the rabbits in experiment group was dead of anesthetic accident and the other were dead 3 days after operation. Length of ureteral defects in experiment group was 6.14±0.10cm, and 2 of them were necrosis. 10 kidneys and ureters from the experimental group were grossly normal, appeared promptly on intravenous urography, and were patent on retrograde pyelography. In 6 weeks, the stoma was covered by transitional epithelium and part of intestines mucosa was replaced by ureteral transitional epithelial cell. The intestine crypt and intestinal villi were atrophied in 12 weeks. There are no differences between the experiment and control group in serum creatinine, urea nitrogen and electrolytes (P>0.05). Replacing the ureter by an ileal segment using the Yang-Monti procedure has no effect on renal function.Conclusions: In the rabbit model, the Yang-Monti principle of tailoring pedicle ileum substitution for long ureteral defects is fairly an ideal technical surgery which could accommodated long segment ureter defect, do little interfere with physiological function of ileum. Renal function remained intact, and no evidence of stricture was demonstrated on radiographicimaging. Applying the technic of microsurgery anastomosis can also degrade the incidence rate of stenostomia and urinary fistula.