Bladder stones are a clinically relevant pediatric urological condition that may require endoscopic treatment. Transurethral Holmium:YAG laser cystolithotripsy is a minimally invasive option for selected children with bladder stones.

This prospective randomized trial will compare two Holmium:YAG laser strategies during transurethral cystolithotripsy in children with a single bladder stone less than 3 cm: dusting and fragmentation. Children will be randomized to undergo laser dusting or laser fragmentation during transurethral cystolithotripsy.

The primary outcome is total operative time. Secondary outcomes include laser time, need for active fragment extraction, endoscopic stone-free status at the end of the procedure, ultrasound-assessed stone-free status during follow-up, intraoperative complications, postoperative urinary symptoms, urinary tract infection, need for postoperative catheterization, and hospital stay.

This is a prospective randomized controlled trial conducted at the Department of Urology, Faculty of Medicine, Beni-Suef University Hospital.

The study will include children with radiologically confirmed single bladder stones less than 3 cm who are planned for transurethral Holmium:YAG laser cystolithotripsy and are suitable for transurethral endoscopic management under general anesthesia. Written informed consent will be obtained from parents or legal guardians before enrollment.

Eligible children will be randomized in a 1:1 ratio into two groups. Participants in the dusting group will undergo transurethral Holmium:YAG laser cystolithotripsy using low pulse energy and higher pulse frequency settings, with the aim of reducing the stone into fine particulate debris and tiny fragments with minimal need for active extraction. Participants in the fragmentation group will undergo transurethral Holmium:YAG laser cystolithotripsy using higher pulse energy and lower pulse frequency settings, with the aim of producing visible extractable fragments that can be actively removed when needed.

All procedures will be performed under general anesthesia in the lithotomy position using a pediatric semi-rigid ureteroscope. A Holmium:YAG laser will be used in both groups. The planned settings are 0.5-0.8 J and 10-15 Hz in the dusting group, and 1.0 J and 6-10 Hz in the fragmentation group. A 550-micron end-firing laser fiber will be preferred when compatible with the available endoscope.

The primary outcome is total operative time, defined as the time in minutes from insertion of the endoscope into the urethra until completion of stone clearance and termination of the procedure, including fragment retrieval when required. Secondary outcomes include laser time, need for active fragment extraction, endoscopic stone-free status at the end of the procedure, ultrasound-assessed stone-free status at follow-up, intraoperative mucosal injury or bleeding, need for postoperative catheterization, postoperative hematuria, dysuria, urinary tract infection, and hospital stay. Follow-up will be scheduled at 1 week, 1 month, and 3 months with clinical assessment and ultrasonography.

Inclusion Criteria:

1. Children aged less than 18 years.
2. Radiologically confirmed single bladder stone less than 3 cm.
3. Suitable for transurethral cystolithotripsy.
4. Fit for general anesthesia.
5. Written informed consent from parents or legal guardians.

Exclusion Criteria:

1. Giant bladder stones more than 3 cm.
2. Urethral pathology preventing safe transurethral access.
3. Major lower urinary tract anomaly or neurogenic bladder.
4. Active untreated urinary tract infection.
5. Coagulation disorder or contraindication to endoscopic surgery.

Individual participant data will not be shared. Only aggregated, de-identified study results will be reported. Individual-level pediatric clinical data will remain confidential and will be accessible only to the study investigators and authorized regulatory or ethics committee representatives if required.

The operating surgeon cannot be blinded because of the nature of the laser technique. Participants and their families, as well as postoperative outcome assessors, will remain blinded to treatment allocation whenever possible.