Efficacy of electromagnetic extracorporeal shockwave lithotripsy on high-density ureteral stones

Introduction: Our aim was to evaluate electromagnetic extracorporeal shockwave lithotripsy (SWL) in treating high-density radiopaque ureteral stones on non-contrast computed tomography (NCCT).

Patients and methods: Adult patients with radiopaque stones in the ureter who underwent SWL in a high volume center between 2016 and 2017 were retrospectively included. NCCT characteristics such as mean stone density (MSD), stone size, skin to stone distance (SSD) were recorded before treatment. Treatment success was defined as complete stone clearance (SF).

Results: 108 patients were included. Global stones MSD was 1119 HU. 55% and 62% of patients were SF respectively after 1 and 2 sessions of SWL. There was no difference of success rates between the treatment of low MSD (<1000 HU, n=33) and high MSD (≥1000 HU, n=75) (P=0.57, OR=0.79, 95% CI [0.35-1.80]). The SF rate dropped to 31.6% for 19 patients with ureteral stenting before treatment (P=0.02, OR=3.34, 95% CI [1.16-9.62]). Mean stone size was 7.2mm, SF rate for stones over 7mm were statistically lower (P=0.04, OR=2.18, 95% CI [1.00-4.73]). 4 patients needed ureteral stenting in emergency after SWL (3.7%).

Discussion: Electromagnetic SWL is a safe and effective way to treat ureteral stones. A high-density stone on NCCT may not be detrimental. Many parameters should be involved in the treatment decision such as stone size and ureteral stenting.

Level of proof: 4.