Influence of stent size on the success of antegrade endopyelotomy for primary ureteropelvic junction obstruction: Results of 2 consecutive series

Purpose: We evaluated the influence of stent size in 2 consecutive series of unselected patients in whom primary ureteropelvic junction obstruction was managed by antegrade endopyelotomy and stenting with a 14 or 27Fr stent at the level of the incision. Materials and Methods: Antegrade endopyelotomy was performed in 132 patients with primary ureteropelvic junction obstruction. The endopyelotomy was stented for 6 weeks. In 77 patients (group 1) a 14/8.2Fr percutaneous endopyelotomy (Smith) catheter was used. In 55 patients (group 2) a modified 14/8.2Fr Smith catheter was over pulled with a 27Fr wound drain. The wound drain was removed after 2 to 3 weeks and the standard 14/8.2Fr stent remained in place for another 3 to 4 weeks. Success at 6 to 8 weeks, and 6 and 24 months postoperatively was based on clinical evaluation, and excretory urography and/or diuretic renography. Thereafter clinical and ultrasound followup was performed every 2 to 3 years. Results: Preoperatively data on the risk factors of large pyelocaliceal volume and impaired renal function were similar in the 2 groups. The overall success rate was 70% in group 1 at a median followup of 67 months (range 2 to 118) and 94% in group 2 at a median followup of 23 months (range 2 to 52). The early success rate after 6 to 8 weeks in groups 1 and 2 was 83% and 94%, respectively. The long-term success rate after 2 years was 71% and 93%, respectively. Perioperatively and postoperatively the incidence of complications was 16% in group I and 24% in group 2. When group 2 complications due to a lack of experience with the new stent were excluded from analysis, the remaining 15% complication rate was comparable to that in group 1. Mean pyelocaliceal volume decreased significantly in each group and remained stable. Split renal function did not change preoperatively to postoperatively with no significant difference in the 2 groups. Conclusions: Stenting an antegrade endopyelotomy with a modified 27Fr instead of a 14Fr catheter seems to increase the early and, even more impressively, the long-term success rate to a level similar to that of open pyeloplasty.