Ureteral wall thickness as a predictor for non-invasive treatment success for steinstrasse. Can we save time?

PURPOSE: We aimed to define factors affecting the non-invasive overall treatment success (medical expulsive therapy (MET) ± shock wave lithotripsy (SWL)) for uncomplicated ureteral steinstrasse (SS) clearance. METHODS: We retrospectively evaluated consecutive patients who underwent SWL for renal stones between 2017 and 2021. Patients with uncomplicated SS were included. All patient's demographic and radiological data, e.g., age, gender, pre-SWL stenting, SS site, type, leading stone size in widest diameter (< 10 mm and ≥ 10 mm), ureteral wall thickness (UWT) in mm against the leading stone were collected. If SS was diagnosed, medical treatment was given for 4 weeks. In case of MET failure, either SWL for the leading stones + MET or direct URS was done. Non-invasive treatment success (SFR) was considered if complete clearance of SS occurred with no complications or the need for invasive intervention. RESULTS: A total of 145 patients were included with mean age of 45.9 ± 12.4 years. SFR in case of MET only occurred in 27.9%. Complications happened in 26 patients (17.9%). Non-invasive treatment SFR was achieved in 78 patients (53.8%) totally where SS type I, leading stone size ≤ 10 mm type and decreased UWT around the leading stone increased treatment success. CONCLUSION: Ureteral wall thickness is an important factor predicting SS management success. Besides the decreased UWT, non-invasive management should be offered for type I SS with leading stone ≤ 10 mm.

Optimization of shockwave lithotripsy use for single medium sized hard renal stone with stone density ≥ 1000 HU. A prospective study.

PURPOSE: To identify shock wave lithotripsy (SWL) success predictors in hard renal stones (average stone density ≥ 1000 HU). MATERIALS: We prospectively evaluated patients who underwent SWL for hard renal stones between April 2018 and December 2020. Radiological parameters were identified, e.g., stone site, size, the average density in addition to stone core and shell mean density, and renal cortical thickness (RKT). SWL sessions were performed using Doli-S lithotripter till a maximum of 3-4 sessions with 2-4 weeks interval. Initial response to SWL included stone fragmentation and decreased stone size after the first SWL. Treatment success was considered if complete clearance of renal stones occurred or in case of clinically insignificant residual fragments ≤ 4 mm after 12 weeks follow up by NCCT. RESULTS: Out of 1878 patients who underwent SWL, the study included 157 patients with hard renal stones. Treatment overall success was found in 92 patients (58.6%) where 69 patients (43.9%) had complete stone clearance. On multivariate analysis, stone shell density < 901 HU, maximum stone size < 1 cm, RKT > 1.95 cm and initial treatment response were associated with increased the success rate after SWL for hard renal stones (P = 0.0001, 0.009, < 0.0001 and < 0.0001, respectively). CONCLUSION: In hard renal stones, treatment overall success was found in 58.6% where complete stone clearance was found in 43.9%. Stone outer shell fragility, lower stone size, increased RKT and initial response to SWL were associated with a higher success rate at 12-week follow-up.