Long-term results of prosthetic ureteral replacement in minipigs

In a 3-year study, silicone rubber prostheses were implanted in 6 minipigs as ureteric replacement. A Dacron velour cuff was applied for the proximal anastomosis and a disc of the same material implanted into the bladder wall to anchor the prosthesis distally. The silicone tube incorporated a metal spiral to prevent kinking. On autopsy all anastomoses were firm and resistant to tearing except in 1 animal where the proximal end of the prosthesis had loosened without further complications. Incrustation or leakage never occurred. On histology dense ingrowth of collagen fibres into the meshes of Dacron velour was evident. Malignant cells could never be demonstrated. The findings are compared with a previous 12-month study. The growth of polypoid structures occluding the prosthesis was found to be a new problem with long-term alloplastic ureteric replacement. The best results were achieved with unilateral prostheses after contralateral nephrectomy.