Comparison of Ureteral Stent Designs in Children With Kidney Stones

This study will compare two commonly used ureteral stents in children and adolescents undergoing staged treatment for kidney stones. Ureteral stents are small tubes placed between the kidney and bladder to help urine drain after a procedure. Although stents are effective, they can cause bladder spasms, pain, urinary urgency, and other uncomfortable symptoms. Participants aged 8 to 18 years will receive both a standard Cook double-J ureteral stent and a Polaris Ultra ureteral stent during two planned procedures. The order in which the stents are used will be assigned at random, and participants and caregivers will not be told which stent is in place during each treatment period. Participants will report bladder spasms, pain, urinary symptoms, and quality of life through questionnaires and symptom assessments. The study will determine whether differences in stent design affect comfort, bladder spasms, urinary tract infections, or other stent-related complications. Both stents are approved by Health Canada and are used as part of routine clinical care.

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.