Prospective, Randomized Trial Comparing Soft and Firm Ureteral Stents

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.