OBJECTIVE: Analysis of the effect of technical factors, i.e. the type of stone targeting and shock wave generator, on ESWL efficacy. Evaluation of secondary outcomes to determine an optimal strategy for performing the procedure. PATIENTS AND METHOD: In the period from 01/2016 to 07/2021, we analyzed data from patients indicated for ESWL for nephrolithiasis and proximal or distal ureterolithiasis. This was a tricenter retrospective study to evaluate stone-free rates (SFR) while taking into account the number of ESWL sessions in four selected groups of patients with comparable characteristics. A patient is considered stone-free in the absence of residual lithiasis or with an asymptomatic residue of up to 2 mm. The real-time ultrasound-guided (USG) arm consisted of a group of 120 patients on the electromagnetic STORZ SLK lithotripter in the period from 02/2017 to 02/2020. A total of three comparison arms with x-ray guidance were created: A: 68 patients between 01/2016 and 03/2017 on the Medilit 7 electrohydraulic lithotripter. B: 72 patients from 04/2017 to 10/2017 on the Sonolith i-sys electroconductive lithotripter (EDAP). C: 120 patients from 03/2018 to 07/2021 on the STORZ SLK electromagnetic lithotripter. By comparing the US and x-ray guidance using the STORZ SLK lithotripter, the effect of targeting when using an identical device (electromagnetic generator) was evaluated. By comparing the arms A, B, and C, the efficacy in different types of generators - electromagnetic, electroconductive, electrohydraulic - was assessed when the same type of targeting (fluoroscopy) was used. The secondary parameters that were monitored included: the rate of use of auxiliary techniques in stone management; radiation exposure for the patient and/or operator; analgesic consumption; and the time required to perform the procedure. RESULTS: When US versus x-ray guidance was compared in an electromagnetic lithotripter, SFRs of 90% vs. 85% (P=0.329), i.e. statistically comparable results, were obtained. By comparing electromagnetic, electroconductive, and electrohydraulic generators with fluoroscopy, SFRs of 85%, 88.9%, and 88.2% were obtained, respectively (P=0.727). When the degree of need for intraoperative analgesic administration was assessed, the electromagnetic generator was found to have a significantly lower consumption (20.8% vs. 30.6% vs. 48.5%) (P=0.0005). Values less than 1095 HU and 108.5 mm were shown to be optimal cut-off values for stone density and skin-to-stone distance, respectively. CONCLUSION: Based on our comparative analysis, the noninferiority of US stone targeting was demonstrated compared to fluoroscopic targeting. No significant differences in ESWL efficacy were found using electrohydraulic, electroconductive or electromagnetic shock wave generators. With the electromagnetic lithotripter, there was a significantly lower analgesic consumption than with the electrohydraulic type.

Department of Urology Faculty of Medicine and Dentistry Palacky University Olomouc and University Hospital Olomouc Czech Republic

Department of Urology Hanusch Krankenhaus Vienna Austria

See more in PubMed

Türk C, Neisius A, Petrik A, Skolarikos A, Seitz C, Somani B, Thomas K, Gambaro G. EAU Guidelines on Urolithiasis 2021. EAU Guidelines Office; Arnhem; The Netherlands.

Kaynar M, Tekinarslan E, Keskin S, Buldu I, Sönmez MG, Karatag T, Istanbulluoglu MO. Effective radiation exposure evaluation during a one-year follow-up of urolithiasis patients after extracorporeal shock wave lithotripsy. Cent European J Urol 2015;68(3):348-52. doi:10.5173/ceju.2015.547 PubMed DOI

Abid N, Ravier E, Promeyrat X, Codas R, Fehri HF, Crouzet S, Martin X. Decreased Radiation Exposure and Increased Efficacy in Extracorporeal Lithotripsy Using a New Ultrasound Stone Locking System. J Endourol 2015;29(11):1263-9. doi: 10.1089/end.2015.0175 PubMed DOI

Smith HE, Bryant DA, KooNg J, Chapman RA, Lewis G. Extracorporeal shockwave lithotripsy without radiation: Ultrasound localization is as effective as fluoroscopy. Urol Ann 2016;8(4):454-57. doi: 10.4103/0974-7796.192104 PubMed DOI

Van Besien J, Uvin P, Hermie I, Tailly T, Merckx L. Ultrasonography Is Not Inferior to Fluoroscopy to Guide Extracorporeal Shock Waves during Treatment of Renal and Upper Ureteric Calculi: A Randomized Prospective Study. Biomed Res Int 2017;2017:7802672. doi: 10.1155/2017/7802672 PubMed DOI

Mustafa M, Aburas H, Helo FM, Qarawi L. Electromagnetic and Electrohydraulic Shock Wave Lithotripsy-Induced Urothelial Damage: Is There a Difference? J Endourol 2017;31(2):180-84. doi:10.1089/end.2016.0644 PubMed DOI

Lee CC, Lin WR, Hsu JM, Chow YC, Tsai WK, Chiang PK, Chen M, Chiu AW. Comparison of electrohydraulic and electromagnetic extracorporeal shock wave lithotriptors for upper urinary tract stones in a single center. World J Urol 2019;37(5):931-35. doi: 10.1007/s00345-018-2464-7. PubMed DOI

Qin, Jun. Numerical Analysis of Bubble Dynamics in Electrohydraulic and Electromagnetic Shock Wave Lithotripsy. Int J Comput Biol Drug Des 2015;8(2):105-13. doi:10.1504/IJCBDD.2015.071126 DOI

Goren MR, Goren V, Ozer C. Ultrasound-Guided Shockwave Lithotripsy Reduces Radiation Exposure and Has Better Outcomes for Pediatric Cystine Stones. Urol Int 2017;98(4):429-35. doi: 10.1159/000446220 PubMed DOI

Zisman A, Assadi A, Goldin O, Malshy K, Nativ O, Meretyk S, Amiel GE, Mullerad M, Livne PM. Shock Wave Lithotripsy in Pediatric Stone Disease: A 15-Year Single-Center Experience with 2 Types of Lithotripters. Urol Int 2022 Feb 16:1-5. [Epub ahead of print] doi: 10.1159/000522079 PubMed DOI