Dusting vs Fragmentation Laser Cystolithotripsy for Pediatric Bladder Stones (DUST-FRAG-PED)

Dusting Versus Fragmentation With Holmium:YAG Laser During Transurethral Cystolithotripsy in Pediatric Bladder Stones: A Prospective Randomized Trial

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.

Study Overview

• Status: Recruiting
• Conditions: Pediatric Bladder Stones; Pediatric Urolithiasis; Bladder Calculi
• Intervention / Treatment: Procedure: Dusting Holmium:YAG Laser Cystolithotripsy; Procedure: Fragmentation Holmium:YAG Laser Cystolithotripsy

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 110
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hany F Badawy, MD; Phone Number: +201149525028; Email: Hanyfathy86@gmail.com
• Study Contact Backup: Name: Ghada S Etman, MD; Phone Number: +2010 07913852; Email: DrhanYFATHY86@GMAIL.COM

Study Locations

• Egypt
  • Beni Suweif Governorate
    • Banī Suwayf, Beni Suweif Governorate, Egypt
      • Recruiting
      • Department of Urology- Beni-Suef University Hospitals
      • Contact: Hany F Badawy, MD; Phone Number: +201149525028; Email: Hanyfathy86@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dusting; Participants will undergo transurethral Holmium:YAG laser cystolithotripsy using a dusting strategy with low pulse energy . The planned settings are 0.5-0.8 J and 10-15 Hz, aiming to reduce the bladder stone into fine particulate debris and tiny fragments with minimal need for active fragment extraction.	Procedure: Dusting Holmium:YAG Laser Cystolithotripsy; Transurethral Holmium:YAG laser cystolithotripsy using a dusting strategy with planned laser settings of 0.5-0.8 J and 10-15 Hz, aiming to reduce the bladder stone into fine particulate debris and tiny fragments with minimal need for active fragment extraction.
Active Comparator: Fragmentation; Participants will undergo transurethral Holmium:YAG laser cystolithotripsy using a fragmentation strategy with higher pulse energy. The planned settings are 1.0 J and 6-10 Hz, aiming to produce visible extractable stone fragments, approximately 2-5 mm, with active fragment removal when needed.	Procedure: Fragmentation Holmium:YAG Laser Cystolithotripsy; Transurethral Holmium:YAG laser cystolithotripsy using a fragmentation strategy with planned laser settings of 1.0 J and 6-10 Hz, aiming to produce visible extractable stone fragments of approximately 2-5 mm, with active fragment removal when needed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Operative Time	Total operative time will be measured in minutes from insertion of the endoscope into the urethra until completion of bladder stone clearance and termination of the procedure, including active fragment retrieval when required.	During the index transurethral cystolithotripsy procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Laser Time	Laser time will be measured in minutes as the cumulative duration of active Holmium:YAG laser firing during the index transurethral cystolithotripsy procedure.	During the index transurethral cystolithotripsy procedure
Need for Active Fragment Extraction	The need for active fragment extraction will be recorded as whether stone fragments required active removal using endoscopic retrieval maneuvers during the index transurethral cystolithotripsy procedure.	During the index transurethral cystolithotripsy procedure
Endoscopic Stone-Free Status at the End of the Procedure	Endoscopic stone-free status will be assessed at the end of the procedure and defined as no visible residual bladder stone fragments on final endoscopic inspection.	At the end of the index transurethral cystolithotripsy proced
Postoperative Hematuria	Postoperative hematuria will be recorded based on clinical observation or patient/guardian report during postoperativ follow-up.	From the end of the procedure to 1 month postoperatively

Collaborators and Investigators

• Sponsor: Beni-Suef University
• Investigators: Principal Investigator: Hany F Badawy, MD, Faculty of Medicine, Beni-Suef University hospital

Study record dates

Study Major Dates

• Study Start (Actual): May 6, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: May 28, 2026
• First Submitted That Met QC Criteria: May 28, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Dusting; Fragmentation; Transurethral cystolithotripsy; Holmium:YAG laser; Bladder stone surgery
• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urolithiasis; Urinary Calculi; Urinary Bladder Diseases; Pathological Conditions, Signs and Symptoms; Urinary Bladder Calculi
• Other Study ID Numbers: FMBSUREC05052026BadawyDF; FMBSUREC/05052026/Badawy (Other Identifier: FM-BSU REC)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No