Warm coupling fluid reduces pain during extracorporeal shock wave lithotripsy without compromising stone fragmentation: A prospective controlled study
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Published on: December 23, 2022
Ahmet Murat Bayraktar1, Onur Küçüktopçu2, Bilgi İşler2
1Department of Urology, University of Health Sciences Konya City Hospital, Konya, Türkiye. drahmetbayraktar@gmail.com.
Purpose:
Pain during extracorporeal shock wave lithotripsy (ESWL) adversely affects compliance and outcomes. Evidence on the impact of coupling fluid temperature on pain is scarce. We evaluated the effect of coupling fluid temperature on pain and fragmentation efficacy.
Materials And Methods:
This prospective non-randomized controlled study included 368 patients who underwent ESWL at a tertiary urology clinic between July 2023 and December 2025. Patients were allocated into two groups: warm coupling fluid (WCF) (38℃-42℃, n=113) and room-temperature coupling fluid (RCF) (n=255). All procedures were performed using an electromagnetic lithotripter. Outcomes were visual analog scale (VAS) pain score (primary) and stone fragmentation success (secondary).
Results:
The VAS score was significantly lower in the WCF group (4.00±1.34 vs. 5.37±2.01, p<0.001). No patients in the WCF group reported very severe pain (VAS ≥8), whereas the rate was 20.8% (53/255) in the RCF group (p<0.001). Fragmentation success rates were similar between groups (54.0% [61/113] vs. 58.4% [149/255], p=0.426). In ordinal logistic regression, RCF was associated with higher odds of more severe pain (odds ratio 4.010, 95% confidence interval 2.590-6.208, p<0.001).
Conclusions:
WCF significantly reduced procedural pain during ESWL without compromising fragmentation, and this effect was robust across propensity score-based sensitivity analyses. Given its low cost and ease of application, it represents a promising non-pharmacological adjunct in ESWL. Future randomized sham-controlled studies are warranted.
