Çanakcı C. et al., 2025: Comparison of 2 different fluoroscopy activation intervals in shock wave lithotripsy: a prospective randomized study.

Cengiz Çanakcı, Ahmet Şahan, Orkunt Özkaptan, Erdinç Dinçer, Utku Can, Alper Coşkun 
Wideochir Inne Tech Maloinwazyjne. 2025 Apr 17;20(2):152-156. doi: 10.20452/wiitm.2025.17947

Abstract

Introduction: Intermittent fluoroscopic controls are required during shock wave lithotripsy (SWL) to readjust the probe due to patients' movements, respiratory movement, and stone displacement within the kidney. However, there is still no consensus in the literature on the optimal frequency of fluoroscopic monitoring.

Aim: Our aim was to determine the optimal fluoroscopy activation interval in fluoroscopy‑guided SWL and examine its effect on fluoroscopy time and stone‑free status.

Materials and methods: This prospective randomized study included patients with opaque renal pelvic stones smaller than 2 cm, subjected to fluoroscopy‑guided SWL between July 2020 and January 2024. The patients were divided into 2 groups. Fluoroscopic control was performed every 250 shocks in group 1, and every 500 shocks in group 2. Demographic data, calculus volume and density, skin‑to‑stone distance, number of shots and sessions, fluoroscopy duration, and stone‑free status were analyzed.

Results: The data of 158 randomly included patients (equally divided between both groups) were analyzed. No differences were observed between the groups in terms of demographic data and stone parameters. However, there was a difference in fluoroscopy time, which was longer in group 1 than in group 2 (mean [SD], 217.9 [90.2] vs 117 [37] s, respectively; P <0.001). No differences in stone‑free status between the groups were observed (group 1; 64.5%; group 2, 67%; P = 0.87).

Conclusions: Reducing fluoroscopy activation interval in SWL does not affect stone‑free status, but it helps limit radiation exposure.

Wideochir Inne Tech Maloinwazyjne. 2025 Apr 17;20(2):152-156. doi: 10.20452/wiitm.2025.17947. PMID: 40785738; PMCID: PMC12329550

Comment Hans-Göran Tiselius

I doubt that this method of standardized fluoroscopic controls during the shock wave session is generally applicable.
Precise focusing has become even more important than it was previously with the small focus areas that currently are the standard. One reason for checking the position of the stone(s) fluoroscopically is to make sure that there is no change in position either of the stone within the kidney or of the patient on the treatment table. It is not mentioned in this report in how many fluoroscopic controls that it was necessary to make any adjustment of the position. If so, how long had the stone been out of focus and in need of re-alignment??
With a standardized program of the type shown in this article it appears as if the whole SWL-treatment is very stereotypic.
My own experience is that precise focusing requires more frequent but short fluoroscopic controls to fine-tune the re-alignment of the stone and the shock wave.
Nothing is mentioned about the size of the fluoroscopic field. How were the collimators used?

Hans-Göran Tiselius