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 o f unselected patients in whom primary ureteropelvic junction obstruction wa s managed by antegrade endopyelotomy and stenting with a 14 or 27Fr stent a t the level of the incision. Materials and Methods: Antegrade endopyelotomy was performed in 132 patient s with primary ureteropelvic junction obstruction. The endopyelotomy was st ented for 6 weeks. In 77 patients (group 1) a 14/8.2Fr percutaneous endopye lotomy (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 mont hs postoperatively was based on clinical evaluation, and excretory urograph y and/or diuretic renography. Thereafter clinical and ultrasound followup w as performed every 2 to 3 years. Results: Preoperatively data on the risk factors of large pyelocaliceal vol ume and impaired renal function were similar in the 2 groups. The overall s uccess rate was 70% in group 1 at a median followup of 67 months (range 2 t o 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 9 4%, respectively. The long-term success rate after 2 years was 71% and 93%, respectively. Perioperatively and postoperatively the incidence of complic ations was 16% in group I and 24% in group 2. When group 2 complications du e to a lack of experience with the new stent were excluded from analysis, t he remaining 15% complication rate was comparable to that in group 1. Mean pyelocaliceal volume decreased significantly in each group and remained sta ble. 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 inste ad of a 14Fr catheter seems to increase the early and, even more impressive ly, the long-term success rate to a level similar to that of open pyeloplas ty.