Extracorporeal shockwave lithotripsy without radiation: Ultrasound localization is as effective as fluoroscopy

Extracorporeal shockwave lithotripsy (SWL) is the first-line treatment for renal calculi in most cases. Recent technology has allowed lithotriptor machines to localize stones using fluoroscopy or ultrasound (US).

The aim of this study is to compare stone free rates (SFR) using two techniques.

This is a single center retrospective cohort study. We have studied 95 patients with renal calculi undergoing first SWL treatment with localization using US (48 pts) and fluoroscopy (47 pts). SFR was defined as fragments ≤2 m at 4 weeks post procedure on x-ray or US. Patient records were reviewed.

Stone size and location, age and body mass index were comparable between groups. Stones ≤7 mm had better SFR with US 86% (18/21) compared to fluoroscopy 59% (10/17) P= 0.08. Overall the US group had similar SFR to the fluoroscopy group for stones of all sizes and locations with 60% (29/48) compared to 45% (21/47)P= 0.18. Radiation exposure was the biggest difference between techniques with a mean radiation dose (mGy/cm²) in the US group of 103 (0-233) and 2113 (241-7821) in the fluoroscopy group. Radiation use in the US group was due to the use of a single shot pre- and post-procedure, this could be reduced to zero.

Our data show equivalent outcomes using US compared to the traditional fluoroscopy localization technique. We would encourage departments to develop the use of US localization to reduce radiation exposure to patients.