Experimental and clinical experience with new pyeloureteral stents in pediatric urology.

Abstract

In light of the many problems with the use of conventional external stents in supravesical reconstructive urinary tract surgery in children; e.g. the risk of infection, urodynamic malfunction, and lack of flexibility insertion methods, the return to internal pyeloureteral stenting is a much discussed topic in pediatric urology. In order to improve the generally unsatisfactory situation, we developed, together with the Rüsch Co., a new type of directable and deconnectable ureteral stent. This polyurethane catheter features a membrane valve made of soft Wiruthan at the bladder end, which closes automatically with increasing bladder pressure. Thus, urinary backflow from the urinary bladder into the renal pelvis is prevented. Experimental data from antireflux stenting justify the clinical use of such a stent in children, as the urodynamic in vivo criteria and requirements were fulfilled completely. We now have clinical experience with the application of 340 pyeloureteral DD stents in 241 children from 1993 through 1996; 259 stents were inserted intraoperatively, and 81 stents were applied by endoscope. It was impressive that secondarily, renal function that had been considerably reduced could be regained and stabilized by long-term stenting, even in some older children with chronic supravesical ureteral obstruction. Although small technical details have to be clarified, such as simplification of stent retrieval and an antireflux valve that can be applied using an anterograde approach, the DD valve stent used in this patient population after reconstruction of a malformed supravesical urinary tract can be recommended without any reservations.