This prospective multicenter randomized controlled trial will compare stent-related symptoms after placement of a ComfiJ ureteral stent versus a conventional double-J ureteral stent in adult patients undergoing unilateral ureteroscopy or retrograde intrarenal surgery for urinary stones when short-term postoperative ureteral stenting is clinically indicated. Eligible patients will be randomized intraoperatively after the operating surgeon confirms the need for postoperative stenting. The primary outcome will be the Ureteral Stent Symptom Questionnaire urinary symptoms domain score on postoperative day 14 before planned stent removal.

Ureteral stents are frequently used after ureteroscopy and retrograde intrarenal surgery when temporary postoperative drainage is clinically indicated. However, ureteral stents may cause urinary symptoms, pain, hematuria, impaired daily activity, and reduced quality of life. Stent-related morbidity is therefore an important patient-centered outcome in endourology.

This study will compare a ComfiJ ureteral stent with a conventional double-J ureteral stent in adult patients undergoing unilateral ureteroscopy or retrograde intrarenal surgery for urinary stones. Randomization will be performed only after the surgeon has determined intraoperatively that postoperative stenting is required. Patients will be randomized in a 1:1 ratio to receive either a ComfiJ ureteral stent or a conventional double-J ureteral stent. The planned stent dwell time will be 14 days whenever clinically feasible.

The patient and postoperative outcome assessor will be blinded to treatment allocation. The operating surgeon will not be blinded because the stent type is visible during insertion. Stent-related symptoms will be assessed using the validated Arabic Ureteral Stent Symptom Questionnaire, together with pain scores, analgesic use, emergency visits, complications, stent migration, ease of insertion and removal, and patient satisfaction.

Inclusion Criteria:

• Age 18 to 80 years.
• Adult patients undergoing unilateral ureteroscopy or retrograde intrarenal surgery for ureteric or renal stones.
• Intraoperative confirmation that short-term postoperative ureteric stenting for approximately 2 weeks is clinically indicated.
• Indications for postoperative stenting may include ureteric edema, minor ureteric mucosal trauma, need for ureteric dilatation, ureteral access sheath use with expected postoperative edema, impacted stone, residual dust or fragments requiring temporary drainage, or prolonged procedure.
• Ability to understand and complete the Arabic Ureteral Stent Symptom Questionnaire.
• Ability to provide written informed consent.

Exclusion Criteria:

• Cases in which no postoperative ureteric stent is clinically indicated.
• Cases requiring prolonged urinary drainage or major reconstructive decision-making.
• Bilateral ureteroscopy or retrograde intrarenal surgery.
• Solitary kidney.
• Major ureteric injury or ureteric perforation.
• Preoperative febrile urinary tract infection or sepsis.
• Pregnancy or breastfeeding.
• Neurogenic bladder.
• Overactive bladder syndrome.
• Major neurological disease or psychiatric disease affecting symptom reporting.
• History of major bladder, prostate, or pelvic surgery likely to confound stent-related symptoms.
• Concomitant use of alpha-blockers, anticholinergics, chronic analgesics, or other medications likely to alter symptom evaluation.
• Other acute medical conditions that might influence the Ureteral Stent Symptom Questionnaire pain score, including acute pancreatitis, acute gastroenteritis, or musculoskeletal disorders.
• Known allergy to any study-related medication or device material.
• Inability to comply with the follow-up schedule.

Individual participant data will not be shared because the study involves individual-level clinical, operative, and patient-reported symptom data from a multicenter interventional trial. Only aggregated, de-identified study results will be reported in publications or presentations. Any future data sharing request will require approval from the Research Ethics Committee, Faculty of Medicine, Beni-Suef University, and the corresponding ethics committees of the participating centers.

The operating surgeon cannot be blinded because the stent type is visible during insertion. Participants and postoperative outcome assessors will remain blinded to treatment allocation during postoperative symptom assessment.