prospective, randomized trial comparing soft and firm ureteral stents

Conditions: Urolithiasis

Summary: the goal of this clinical trial is to evaluate whether ureteral stent type impacts stent-related symptoms and quality of life in patients undergoing ureteroscopy (urs) and stone lithotripsy for ureteral stones. the main questions it aims to answer are: * does a soft polymer stent reduce stent-related symptoms compared to a firm polymer stent? * does stent type affect intra- and postoperative complications? researchers will compare patients receiving a soft polymer stent (universa®, cook medical) to those receiving a firm polymer stent (percuflex®, boston scientific) to determine if soft stents improve patient comfort and quality of life while maintaining a similar safety profile. participants will: * undergo urs and stone lithotripsy for ureteral stones. * be randomly assigned to receive either a soft or firm ureteral stent. * complete the ureteral stent symptoms questionnaire (ussq) upon stent removal, 14 days after urs.

study design and patient selection 1. study period and ethical approval: * conducted between july 2023 and july 2024 following institutional review board approval (smc 0119-23). * informed consent obtained from all participants. * adhered to the declaration of helsinki. 2. stent types and randomization: * soft stent: universa® (cook medical). * firm stent: percuflex™ plus (boston scientific). * randomization in a 1:1 ratio using asymptomatic maximal randomization. surgical technique and intervention operative team included three fellowship-trained endourologists. procedure details: * ureteroscopy performed using standard 6.5/8.5fr semi-rigid ureteroscope. * lithotripsy performed using a 120w holmium:yag laser (0.3 joule, 40 hertz, dusting technique). stent placement was performed using a 0.038 inch glide wire. 6fr stents used, either soft or firm polymer material, according to randomization. proximal stent curls positioned in the upper calyx/renal pelvis; distal curls in the bladder. postoperative care stent removal was scheduled 2 weeks post-procedure, ans performed using a flexible cystoscope in the outpatient clinic. symptoms assesed using the ureteral stent symptoms questionnaire (ussq) that was completed at the stent removal visit. statistical analysis 1. sample size calculation: * based on a 3-point difference in ussq index score between groups. * assumed 5% type i error and 80% power. * adjusted for a 10% dropout rate; target sample size: 140 patients. 2. data blinding: * patients, data collectors, and analysts blinded to allocation. * since blinding the surgeons to stent type was impossible, surgeons were not involved in data collection or analysis. 3. analysis methods: * continuous variables: mann-whitney u test; median and iqr. * categorical variables: pearson's chi-square or fisher's exact test; frequencies and proportions. * multivariate linear regression for ussq index and urinary domain scores. * statistical significance set at p\<0.05. * analyses conducted using ibm spss v26. this protocol ensures a rigorous and reproducible methodology for evaluating the impact of stent type on patient-reported outcomes following ureteroscopy and lithotripsy.

Eligibility criteria:
inclusion criteria: * patients aged over 18 years * ureteral stones measuring up to 2cm requiring urs and laser lithotripsy exclusion criteria: * pediatric patients * bilateral stones requiring bilateral urs and laser lithotripsy, * stone located in the renal pelvis or calyces, * intra-operative complications of any kind, * any residual stones during the procedure, * ureteroscopies in which no stones were treated ("white ureteroscopy").

Keywords: urolithiasis stent-symptoms