Pediatric Urolithiasis

This prospective randomized pilot study will compare vacuum-assisted mini-percutaneous cystolithotripsy with standard transurethral cystolithotripsy for the treatment of bladder stones in children. Forty children aged 2 to 14 years with bladder stone(s) measuring 10 -30 mm will be randomly assigned to one of two surgical approaches. The vacuum-assisted mini-percutaneous group will undergo suprapubic percutaneous access using a mini sheath with suction-assisted fragment evacuation, while the transurethral group will undergo standard transurethral cystolithotripsy. The primary outcome will be total operative time. Secondary outcomes will include stone-free rate ,lithotripsy time and fragment clearance time, urethral mucosal injury, postoperative hematuria, fever, urinary tract infection, sepsis, urinary retention, urinary leakage from the suprapubic tract, catheterization time, hospital stay, postoperative pain, analgesic requirement, need for auxiliary procedures or conversion, and recurrence or urethral stricture-related symptoms during follow-up.

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 study will evaluate whether intravesical aminophylline can facilitate semi-rigid ureteroscopic access in children with distal ureteral stones when the first gentle attempt to enter the ureter is unsuccessful. Children scheduled for semi-rigid ureteroscopy for distal ureteral stones will first undergo the standard gentle attempt to pass the ureteroscope through the ureteric orifice and intramural ureter. If access is achieved, the child will continue standard treatment and will not be randomized. If access is not achieved, the child will be randomized during the operation to receive either intravesical aminophylline or intravesical normal saline placebo. The study solution will be instilled into the bladder for approximately 5 minutes, then drained, and a second gentle ureteroscopic access attempt will be made. The main outcome is successful same-session passage of the intended semi-rigid ureteroscope without balloon dilation. The study will also assess the need for JJ stenting and deferred ureteroscopy, same-session stone treatment, operative outcomes, complications, and early aminophylline-related safety.

This prospective study aims to evaluate the role of shear wave elastography (SWE) as a non-invasive and radiation-free tool for predicting the success of extracorporeal shock wave lithotripsy (ESWL) in pediatric patients with renal stones. Currently, computed tomography (CT)-derived Hounsfield units (HU) are used to estimate stone hardness; however, repeated radiation exposure is a concern in children. SWE may provide an alternative method by assessing stone stiffness using ultrasound. Pediatric patients under 18 years with renal stones (6-20 mm) scheduled for ESWL will be included. SWE measurements will be performed prior to treatment, and patients will be followed for 3 months to assess treatment outcomes. The primary outcome is ESWL success, while secondary outcomes include correlation between SWE and HU, number of ESWL sessions required, prediction of stone composition, and assessment of the relationship between SWE measurements and stone composition. This study seeks to determine whether SWE can serve as a reliable predictor of ESWL outcomes, correlate with stone composition, and reduce the need for radiation-based imaging in children.

The incidence of pediatric urinary system stones has shown an upward trend in recent years, and Extracorporeal Shock Wave Lithotripsy (ESWL) has become one of the most important minimally invasive treatments for pediatric upper urinary tract stones. Currently, the widely used clinical ultrasound mechanical coupling localization mode suffers from issues such as limited scanning degrees of freedom and difficulty in intuitively grasping the spatial relationship between the stone and the focal point. These issues lead to prolonged stone pre-localization times, significant reliance on operator experience, and a steep learning curve for young and primary care physicians, thereby restricting the standardization and widespread promotion of pediatric ESWL. Building upon existing ESWL equipment, this project independently constructs an "Optical Motion Capture-Assisted Ultrasound Pre-localization System." By utilizing multi-camera infrared motion capture to acquire the 3D pose of the ultrasound probe and the shock wave source in real-time and establishing a unified spatial coordinate system, the system achieves automatic conversion and visual display of the stone's position from the ultrasound image to the shock wave focal point coordinates. This guides the operator to quickly complete focal point pre-localization after freely scanning for the stone. Results from preliminary phantom studies and initial clinical pilot experiments indicate that, while maintaining the routine ESWL workflow, this system can significantly shorten the first effective pre-localization time for pediatric stones from approximately 15 minutes to around 5 minutes, without a significant decrease in the stone clearance rate. This suggests the technology possesses good engineering feasibility and clinical application prospects. This study proposes to conduct a single-center, prospective, single-blind randomized controlled clinical trial. Pediatric patients with upper urinary tract stones eligible for ESWL will be randomly assigned 1:1 to an experimental group and a control group. The experimental group will use the Optical Motion Capture-Assisted Ultrasound Pre-localization System for stone pre-localization, while the control group will use the routine ultrasound mechanical coupling localization method. The \*\*primary outcome measure\*\* is the time to first effective stone pre-localization. \*\*Secondary outcomes\*\* include the stone clearance rate evaluated by imaging at 4 and 12 weeks post-operation, the total number of shock waves released and total energy, total procedure time, intraoperative and postoperative complication rates, sedation/anesthesia dosage, and family satisfaction. Additionally, the study will systematically evaluate the system's impact on physician learning curves and work intensity by analyzing the localization success rate of operators with different seniority levels, learning curves (the trend of localization time versus the number of cases), and subjective workload scores. The core scientific question this project aims to answer is: Under the premise of not compromising the therapeutic efficacy and safety of pediatric ESWL, can optical motion capture-assisted ultrasound pre-localization significantly improve stone localization efficiency, reduce operator workload, and shorten the learning curve for young physicians, thereby enhancing the standardization and accessibility of pediatric ESWL? The expected results will provide an evidence-based foundation for optimizing pediatric ESWL localization modes and formulating relevant technical standards and training programs. Furthermore, it will lay the clinical validation groundwork for future intelligent lithotripsy systems integrating functions such as intelligent identification and robotic arm automatic tracking.