Yodplob T. et al., 2025: Modified Seoul National University Renal Stone Complexity Scoring System for Predicting Stone-Free Status After Extracorporeal Shock Wave Lithotripsy.

Tipatai Yodplob, Chinnakhet Ketsuwan 
Res Rep Urol. 2025 Aug 8;17:279-286. doi: 10.2147/RRU.S534829

Abstract

Background: Incorporating the modified Seoul National University Renal Stone Complexity (S-ReSC-R) scoring system into the preoperative evaluation of both retrograde intrarenal surgery and percutaneous nephrolithotomy has proven to be highly effective in predicting stone-free status after each procedure.

Objective: This study aimed to validate the S-ReSC-R scoring system in extracorporeal shock wave lithotripsy (ESWL) and compare it with the Triple D score under the same protocol.

Materials and methods: Data on consecutive patients undergoing ESWL at a tertiary referral center between 2019 and 2021 were retrospectively analyzed. A total of 297 patients who were evaluated with non-contrast CT prior to the procedure and had adequate follow-up data were included in the analysis. The S-ReSC-R score was calculated based on the number of sites affected. Stone-free status was defined as no evidence of residual stones. Receiver operator characteristic (ROC) curves were generated to determine cutoff values for both scoring systems.

Results: The overall stone-free rate (SFRs) after a single session was 60.5%. The average S-ReSC-R score was significantly lower in patients who had successful ESWL than in those with failed ESWL (1.50 vs 2.63, p < 0.001). The SFRs were significantly lower with higher S-ReSC-R scores: 72.4% in the low score (1-2) group, 36.0% in the intermediate score (3-4) group, and 10.5% in the high score (5-12) group (p < 0.001). Multivariate analyses revealed that both the S-ReSC-R score and the Triple D score independently influenced ESWL success (both p < 0.001). The area under the ROC curve for the S-ReSC-R score was 0.767, whereas that for the Triple D score was 0.694.

Conclusion: This study confirms that the S-ReSC-R is a reliable tool for predicting stone-free status after ESWL. Thus, its use in evaluating patients for ESWL is recommended.

Comment Hans-Göran Tiselius

The authors used the S-ReSC-R scoring system and Triple D scores to evaluate the outcome of SWL. The Seoul scoring system is not commonly used, but in this report, it was shown that a low S-ReSC-R score was associated with a higher stone-free rate. The scores were 1.50 and 2.63. In patients with low, intermediate and high scores S-ReSC-R scores, stone-free rates were 72.4%, 36.0% and 10,5%.
There are many nomograms or scores aiming at predicting the outcome of SWL. This is the only system in which the anatomical distribution of the stone burden in the kidney is used. The authors have used it also for RIRS and PCNL. Other factors such as stone density and anatomically unfavorable conditions were not taken into account.
Personally, I am not particularly fond of all nomograms and formula, but rely on clinical experience when deciding whether SWL is suitable or not.
The system used by the authors were as follow:
#1 Stone in renal pelvis
#2 Stone in superior major calyx
#3 Stone in inferior major calyx
#4#5 Stone in superior calyx
#6#7 Stone in middle calyx
#8#9 Stone in inferior calyx
One point is given for stone in each location. One extra point for inferior stone.

Hans-Göran Tiselius