Prospective comparison of two methods for correct ureteral stent placement in pediatric laparoscopic pyeloplasty

Abstract

Ureteral stent placement during laparoscopic pyeloplasty is a common procedure in pediatric patients. Although an apparently safe maneuver, ascending placement of the stent can lead to complex removal or repositioning reinterventions. In this study we compare two methods for intraoperative verification of correct positioning. Prospective observational study collecting data on laparoscopic pyeloplasties in pediatric patients in our center over three years. We carried out descriptive and univariate comparative analyses. Data were compared between ultrasound and reflux visualized by the catheter after intraoperative salineinjection into the bladder through the urethral catheter. We recorded time to catheter visualization in both ultrasonography and in reflux from the start of bladder instillation, as well as bladder volume at the time of placement verification with each method. Data were collected from 20 patients (15 male and 5 female) with a median age of 48 months. Pyeloplasty was successful in 100% of the sample (as observed by ultrasound and MAG-3), while one patient had postoperative leak requiring nephrostomy placement. Correct distal positioning of the ureteral stent could be verified by intraoperative ultrasound and reflux in all cases. Using reflux, the bladder volume needed to verify correct positioning exceeded the age-related maximum in half the cohort, while on ultrasound, the stent was visualized in the bladder without reaching the maximum bladder capacity for age in any case (p=0.02 comparing percentages). Likewise, mean time to verification was lower with ultrasound than with reflux (61.8s versus 115s), but without these differences reaching statistical significance (p=0.14). The present study is the first to compare two methods to verify the correct positioning of the ureteral stent in laparoscopic pyeloplasties in pediatric patients. Our results show that both intraoperative ultrasound and visualization of reflux are useful methods, although ultrasound requires a lower volume of saline instilled through the bladder catheter for verification. This work can be very useful for the daily clinical practice of urologists and pediatric surgeons. Both intraoperative ultrasound and visualization of reflux are useful methods to verify the correct positioning of the ureteral stent in laparoscopic pyeloplasty of pediatric patients. With ultrasound, a smaller volume is required to check for reflux. Although ultrasound is faster for verification, there are no differences in procedural times.