Using of Single-Layer Porcine Small Intestinal Submucosa in Urethroplasty on a Beagle Model

Purpose. To evaluate the role of porcine small intestinal submucosa (SIS) in reducing fistula during urethroplasty and to observe its degradation process in beagle models. Methods. 22 male beagles were divided into the SIS group and control group. All animals received surgical operation to establish the hypospadias model. Urethroplasty was followed. In the SIS group, the urethra was covered with a single-layer SIS material while no SIS material covered in the control group. At the 2nd, 4th, and 12th weeks after the operation, there were 3, 3, and 5 animals in each group, respectively, sacrificed for surgical site histological examinations. The inflammation reaction and collagen hyperplasia levels were assessed. The fistula was identified by retrograde cystourethrography at the 4th and 12th weeks after the operation. Results. the incidence of urethral fistula was 25% (2/8) in the SIS group and 75% (6/8) in the control group. The inflammation reaction of SIS and control groups had no significant difference (U=52.50, P=0.58). The collagen fiber increased in both groups; however, the SIS group had a much more gentle increase compared to the control group (U=-0.00, P < 0.001). In the SIS group, the SIS material was roughly complete on the specimens 2 w after surgery but became loose and discontinuous 4 w after surgery and could not be found 12 w after surgery. Conclusion. The material can decrease the incidence of urethral fistula in the animal models, when used as a coverage layer. The SIS degradation process started 2 w-4 w after the operation and finished before 12 w in the animal model.