Shock Wave Lithotripsy Outcomes for Upper and Lower Ureteral Stones in Non-obese and Non-Pre-stented Adults: Is One Session Sufficient?

Abstract

PurposeThis study aims to evaluate differences in shock wave lithotripsy (SWL) outcomes between upper and lower ureteral stones and identify patients who are likely to have a stone-free status after one session of SWL.Materials and methodsAfter approval from the institutional review board and from a prospectively maintained database of 628 patients, 182 were retrospectively identified, who have had SWL for a single lower or upper ureteral stone and met the inclusion criteria. Age, body mass index (BMI), and stone size were similar among the groups. This study included non-pre-stented patients with solitary lower or upper ureteral radiopaque stones identified on non-contrast-enhanced computed tomography (NCCT), did not have acute obstruction, and had either normal body mass index (BMI) or overweight status. Patients were treated with Sonolith i-sys electroconductive lithotripter (focal length: 21 cm) (EDAP TMS, Vaulx‐en‐Velin, France). Success was defined as the absence of residual of any size or a residual of ≤2 mm on NCCT after one month, whereas failure was having fragments >2 mm or requiring surgical intervention. Post-SWL assessments were completed one week after every session with an X-ray of the kidney-ureter-bladder (KUB-XR) and NCCT after one month.ResultsThe upper and lower ureteral stone-free rates (SFRs) were 95% and 64.7%, respectively. Of them, 65% and 45%, respectively, were stone-free after one session. The cohort having a stone-free status after one SWL session was similar in age, sex, BMI, and stone density. The upper ureteral stone arm has a significant chance for one SFR session with a larger stone size, shocks per session, and maximum power delivered. In the receiver operating characteristic (ROC) curves, the optimal cut point number of sessions of 1.5, mean stone density (MSD) of 895, and stone size of 10.5 mm are the most likely to have successful SWL in the ureter.ConclusionFor patients having ureteral stones with favorable factors, SWL modality is effective and safe. Moreover, SWL can be done for one or two sessions only with the presence of favorable factors.