Use of small intestine submucosa as ureteral allograft in pigs

Purpose: The aim of the present study was to evaluate the biocompatibility of small intestinesubmucosa (SIS) in the reconstruction of the ureter in swine.Materials and Methods: An experimental study was performed in 10 half-breed pigs weighingbetween 20 and 30 K, in which a previously prepared segment of SIS measuring approximately 2.0cm was implanted in the upper third part of the right ureter.Results: Of the 10 operated animals, one died 14 days after the surgery due to a dehiscenceon the suture line of the implanted graft. The remaining 9 animals were submitted to ultrasoundexamination of the urinary tract and were sacrificed on the 40th postoperative day. The macroscopicevaluation showed no calculus, incrustation, fistula, abscesses or adhesions in the ureters with thegraft. Microscopic evaluation with hematoxylin-eosin and Sirius red showed in the experimental area(graft) the presence of urothelium in 100% of the cases, collagen in 100% of the cases, and smoothmuscle layer in 87.5% of the animals. In the area adjacent to the graft (proximal and distal), weobserved 92.86% of urothelium, 42.86% of collagen and 71.43% of smooth muscle. In the contralateralureter, it was found 100% of urothelium and smooth muscle and just 11.11% of collagen. Themicroscopic analysis of the kidneys whose ureters received the graft of SIS evidenced congestion in55.55%, pelvic edema in 66.66% and interstitial nephritis in 77.78%. Hydronephrosis was present in33.33% and chronic pyelonephritis in 44%. Only 1 animal presented total absence of glomerulus inthe renal parenchyma.Conclusion: The SIS graft behaved as a biological tissue support, allowing the regenerationof the urothelium and smooth muscle grow, despite of chronic inflammatory process.Key words : small intestine; submucosa; ureter; graft; swineInt Braz J Urol. 2004; 30: 327-35