Reconstruction of ureteral defects with microvascular vein grafts in a ratmodel

This study was undertaken to test the performance of an autologous vein gra ft as a ureteral replacement in the rat model. Twenty-six rats were divided into three groups. In Group 1 (n = 10), the animals had a 3-mm segment of the ipsilateral ureter excised and the ureteral defect repaired, using a su perficial epigastric vein graft. In Group 2 (n = 10), the same ureteral def ect was created and again repaired, using a superficial epigastric vein gra ft, with the addition of a Silastic stent. The control, Group 3 (n = 6), ha d the ureter transected and repaired solely by means of primary anastomosis . Animals from each group underwent urography and were sacrificed for histo logy at three different postoperative intervals: 1, 4, and 12 weeks. Postop erative urography results showed normal renal function in the animals with ureteral reconstruction using vein grafting aided by a stent, as well as in those with primary ureteral anastomosis. No renal function return was seen in the animals with ureteral reconstruction by vein grafting alone, withou t stent support. Histologically, a progressive loss of the vascular endothe lium, and replacement with the urothelium typical of the ureter, was seen i n the stented vein grafts. Severe ureteral obstruction at the proximal site of the graft and hydronephrosis were seen in the vein-graft group without stenting. This study demonstrates that autologous vein grafts can be used s uccessfully to correct a ureteral deficit, contingent on accurate microsurg ical technique and immediate stenting.