Optical Motion Capture-Assisted Ultrasound for Pediatric ESWL

Condition(s) studied

Investigational drug(s) / intervention(s)

ESWL with Optical Motion Capture-Assisted Ultrasound Localization: Step 1: The physician holds the ultrasound probe to freely scan the patient's target area. Ultrasound images are displayed in real-time to identify and lock onto the stone's position. Step 2: Activate the optical motion capture system. High-speed cameras capture the spatial trajectory of the ultrasound probe, while synchronized AI algorithms recognize the stone image to digitally generate the stone's 3D spatial coordinates. Step 3: The system automatically matches the position of the ultrasound probe with the shock wave source. Using preset algorithms, it drives the robotic arm to fine-tune the posture, completing the focal point alignment between the probe and the wave source. This ensures the stone is precisely located at the central focus of the lithotripsy energy. Once localization is complete, relevant equipment parameters are locked.

ESWL with Conventional Ultrasound Localization: 1. The physician performs a freehand ultrasound scan based on clinical experience to locate the stone and verify its position. 2. The ultrasound probe is secured to the dedicated ultrasound bracket of the Dornier lithotripter. The physician manually adjusts the bracket angle while simultaneously controlling the lithotripter's X, Y, and Z-axis movements. The ultrasound image is repeatedly aligned until the stone is confirmed to be precisely located at the focal point of the shock wave energy. Upon completion of localization, the equipment parameters are locked.

Study summary

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.

Eligibility

Primary outcome measure(s)

• Total Duration of Ultrasound Localization Operation — Timed for the entire duration of a single procedure; calculated immediately upon the conclusion of the operation.
  Defined as the total duration from the initiation of ultrasound localization until the complete conclusion of the target therapeutic procedure (core lithotripsy-related operations) and the withdrawal of instruments. This excludes time for preoperative preparation, anesthesia, and basic postoperative care. It is recorded in real-time using a precise timing tool.

Trial sites (1)

More The Children's Hospital of Zhejiang University School of Medicine trials in China

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