Shock wave lithotripsy okay for treating large kidney stones in children

The factors contributing to the better success of SWL include short SSD, low shock wave rate, percussion diuretics inversion (PDI) approach, alpha-blocker therapy, and 2 minutes break. The authors revealed overall stone-free rate is 93.9%, where 46 patients were rendered stone free after three sessions of SWL.

Considering the high recurrence rates in pediatric urolithiasis, there is a need for non-invasive or minimally invasive treatment such as SWL. Therefore AUA, EAU, and ESPU recommend shock wave lithotripsy as first-line treatment for renal calculi ≤ 2, and percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for renal calculi > 2cm. The authors suggest the superiority of SWL over RIRS and PCNL as it is an outpatient procedure, is inexpensive and has high SFR (stone-free rates) in well-selected cases, particularly paediatrics. On the other hand, SWL therapy has limited efficacy with a lower SFR, and high retreatment rate and/or additional interventions for treating harder and larger renal calculi.

Against the above background, Elnisr Rashed Mohamed, Sohag University, Sohag, Egypt, and colleagues aimed to evaluate the safety and efficacy of SWL for treating renal stone > 2cm to extend its indications for pediatric renal calculi.

For this purpose, the researchers reviewed the records of patients with renal calculi treated by open surgery, RIRS, mini-PCNL, and SWL between 2016 and 2022. The study included forty-nine eligible children aged 1-5 years old, presented with calyceal calculi and/or renal pelvic ith measurement of 2-3.9 cm and underwent SWL therapy.

The researchers also included data from an additional eligible 79 children of the same age with renal pelvic and/or calyceal calculi > 2cm up to stag horn calculi. They underwent open renal surgery, RIRS, and mini-PCNL. They retrieved the following preoperative data from the records of the eligible patients; gender, age, length, weight, renal function tests, urine analysis, weight, and radiological findings (stone size, number, site, side and radiodensity).

They also retrieved outcomes data in the form of fluoroscopy time, operative time, retreatment rates, SFRs, hospital stay and complication rates from the records of patients treated with shock wave lithotripsy and other techniques. They also collected SWL characteristics in terms of; number, position, frequency of shocks, time of the session, voltage and U/S monitoring to evaluate stone fragmentation.

The patients treated with SWL had a mean age of 3.23 ± 1.19 years old, the mean length of the SSD was 8.2 ±1.4cm, and the mean size of the treated calculi was 2.31 ± 0.49. All patients had NCCT scans, and the treated calculi's mean radio density was 583 ± 170.1 HUs based on NCCT scans.

The study led to the following findings:

• Single- and two-session SFRs of SWL therapy were 75.5% and 93.9%, respectively.
• The overall success rate was 95.9% after three-session of SWL.
• Complications were experienced by seven patients in the form of fever (4.1%), vomiting (4.1%), abdominal pain (4/1%), and hematuria (2%). All complications were managed in outpatient settings.
• The results were obtained based on preoperative NCCT scans for all patients, postoperative plain KUB films, and real-time abdominal U/S.
• Single-session SFRs for SWL, mini-PCNL, RIRS and open surgery were 75.5%, 82.1%, 73.6% and 90.6%, respectively.
• Two-session SFRs by the same technique were 93.9%, 92.8%, and 89.7% for SWL, mini-PCNL and RIRS, respectively.
• A lower overall complication rate and higher overall SFR were found with SWL therapy compared to other techniques,

"The replicability and non-invasive nature of the SWL procedure, along with the low complication and high success rates, push us to consider its application for treating pediatric large renal calculi > 2cm over the other more invasive techniques," the researchers wrote.

They explained, "high overall success rate (95.9%) and SFR (93.9%) in our research were attributed to the regular use of the ramping procedure, PDI approach, low shock wave rate and alpha-blocker therapy in all participants and short SSD."

Reference:

Mohamed, E. R., Elmogazy, H. M., Zanaty, A. K., Elsharkawi, A. M., Riad, A. M., & Badawy, A. A. (2023). Extracorporeal Shock Wave Lithotripsy for Treatment of Large Pediatric Renal Pelvic Stone Burden More Than 2 cm. Journal of Pediatric Urology. https://doi.org/10.1016/j.jpurol.2023.06.017