PEDIATRIC UROLOGY

A multicenter, randomized, controlled trial of transureteral and shock wave lithotripsy -- which is the best minimally invasive modality to treat distal ureteral calculi in children?
Basiri A, Zare S, Tabibi A, Sharifiaghdas F, Aminsharifi A, Mousavi-Bahar SH, Ahmadnia H
Urology and Nephrology Research Center (UNRC), Shahid Labbafinejad Medical Center, Shahid Beheshti University, M. C. (SBMU), Tehran, I. R. Iran
J Urol. 2010; 184: 1106-9

• Purpose: Since there is insufficient evidence to determine the best treatment modality in children with distal ureteral calculi, we designed a multicenter, randomized, controlled trial to evaluate the efficacy and complications of transureteral and shock wave lithotripsy in these patients.
  Materials and Methods: A total of 100 children with distal ureteral calculi were included in the study. Of the patients 50 were randomized consecutively to undergo shock wave lithotripsy using a Compact Delta II lithotriptor (Dornier MedTech, Kennesaw, Georgia), and 50 were randomized to undergo transureteral lithotripsy with holmium laser and pneumatic lithotriptor between February 2007 and October 2009. Stone-free, complication and efficiency quotient rates were assessed in each group.
  Results: Mean +/- SD patient age was 6.5 +/- 3.7 years (range 1 to 13). Mean stone surface was 35 mm(2) in the transureteral group and 37 mm(2) in the shock wave lithotripsy group. Stone-free rates at 2 weeks after transureteral lithotripsy and single session shock wave lithotripsy differed significantly, at 78% and 56%, respectively (p = 0.004). With 2 sessions of shock wave lithotripsy the stone-free rate increased to 72%. Efficiency quotient was significantly higher for transureteral vs shock wave lithotripsy (81% vs. 62%, p = 0.001). Minor complications were comparable and negligible between the groups. Two patients (4%) who underwent transureteral lithotripsy sustained a ureteral perforation.
  Conclusions: In the short term it seems that transureteral and shock wave lithotripsy are acceptable modalities for the treatment of distal ureteral calculi in children. However, transureteral lithotripsy has a higher efficacy rate when performed meticulously by experienced hands using appropriate instruments.

• Editorial Comment
  Citing a lack of well-designed randomized controlled trials for the treatment of distal ureteral stones, the authors of this study created a multicenter, randomized, controlled trial, which compared ureteroscopy with extracorporeal shock wave lithotripsy. They enrolled 100 children and randomized 50 of them to ureteroscopy with lithotripsy using primarily a pneumatic lithotripter. The other 50 children underwent shock wave lithotripsy. Success rates were significantly better for the patients who underwent ureteroscopy both at two weeks and at three months. The authors did have two cases of ureteral perforation in the ureteroscopy group, one of which required open surgery to correct. They cited some equipment problems as contributing to these two major complications and one also has to wonder if using a pneumatic lithotripter as opposed to Holmium laser in these patients may have also been a contributing factor. In terms of differences in minor complications, 30 of the patients in the lithotripsy group had some skin bruising and three patients developed “steinstrasse”. There was some mucosal tearing noted in two patients in the ureteroscopy group, which required temporary stent placement.
  Although surgical experience is not accounted for in this study, certainly this is a factor that will have an impact on success rates and complications for these modalities. The results of this randomized controlled trial favor a ureteroscopic approach to distal stones despite the fact that it is a more invasive procedure by nature. Improved instrumentation for pediatric patients as well as routine use of Holmium laser lithotripsy over a pneumatic lithotripter will likely continue to make this modality a safe and more effective option for distal ureteral stone management in the pediatric population.

Dr. M. Chad Wallis
Division of Pediatric Urology
University of Utah
Salt Lake City, Utah, USA
E-mail: chad.wallis@hsc.utah.edu