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Experimental and clinical experience with new pyeloureteral stents in pediatric urology
U Friedrich1, R Vetter, T M Jorgensen
1Pediatric Surgical Clinic, Medical Centre Erfurt, Germany.
Insights
Pediatric urology now favors internal pyeloureteral stents over external ones due to infection risks. A new DD valve stent prevents urinary backflow, improving renal function in children with urinary tract reconstruction.
Area of Science:
- Urology
- Pediatric Surgery
Background:
- Conventional external stents in pediatric reconstructive urinary tract surgery pose risks like infection and urodynamic malfunction.
- Insertion methods for external stents often lack flexibility, complicating procedures.
Purpose of the Study:
- To introduce and evaluate a novel, directable, and deconnectable ureteral stent with an integrated antireflux valve.
- To address the limitations of external stenting in pediatric supravesical urinary tract surgery.
Main Methods:
- Development of a polyurethane catheter with a unique membrane valve at the bladder end that automatically closes against bladder pressure.
- Clinical application of 340 pyeloureteral DD stents in 241 children between 1993 and 1996, with 259 inserted intraoperatively and 81 endoscopically.
- Evaluation of urodynamic criteria and renal function post-stenting.
Main Results:
- The DD valve stent effectively prevents urinary backflow from the bladder into the renal pelvis.
- Experimental data confirmed the stent met urodynamic in vivo criteria, justifying clinical use.
- Significant improvement and stabilization of reduced renal function were observed with long-term stenting, even in cases of chronic obstruction.
Conclusions:
- The developed DD valve stent is a safe and effective option for children undergoing supravesical urinary tract reconstruction.
- Despite minor technical aspects needing refinement, the stent is recommended for clinical use in this patient population.
- The stent offers a viable solution to improve outcomes in pediatric reconstructive 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.