Comparison of Ureteral Stent Designs in Children With Kidney Stones

Inclusion Criteria: * Ability of the participant and/or legally authorized representative to provide written informed consent, with assent obtained from the participant when appropriate, in accordance with institutional policy. * Age 8 to 18 years at the time of enrollment. * Undergoing staged ureteroscopic stone management requiring two sequential ureteral stent placements as part of standard clinical care. * Planned placement of unilateral ureteral stents with an anticipated indwelling duration of approximately 4 to 6 weeks per stent. * American Society of Anesthesiologists Physical Status Classification I or II at the time of surgery. * Ability and willingness of the participant and/or caregiver to comply with study procedures, including completion of symptom assessments and questionnaires at specified time points. * Ability to complete study questionnaires in English, either independently or with caregiver assistance. Exclusion Criteria: * American Society of Anesthesiologists Physical Status Classification III or higher at the time of surgery. * Active urinary tract infection, defined as clinical symptoms consistent with infection and a positive urine culture, at the time of screening or before stent placement. * Significant baseline bladder dysfunction, including neurogenic bladder, overactive bladder requiring chronic anticholinergic therapy, or prior bladder augmentation, that could confound assessment of stent-related symptoms. * Requirement for bilateral ureteral stent placement or planned bilateral ureteroscopic procedures. * Known hypersensitivity or allergy to materials used in either ureteral stent included in the study. * Pregnancy or lactation, as determined by clinical assessment and/or institutional testing requirements, where applicable. * Use of chronic opioid therapy, chronic anticholinergic medications, or other medications that, in the investigator's opinion, would substantially interfere with assessment of stent-related pain or urinary symptoms. * Participation in another interventional clinical trial that could interfere with the objectives or outcome assessments of this study.