Development and Face Validation of a Paediatric-Scaled Hydrogel Model for Robot-Assisted Pyeloplasty Training.

1. Background and Rationale Paediatric pyeloplasty is the gold-standard treatment for ureteropelvic junction obstruction (PUJO), yet trainees face a significant "volume crisis" . While an adult urologist may perform 50–150 cases per year, a typical paediatric urologist performs only 5–20 . This rarity makes simulation the primary driver for achieving operative proficiency Current training modalities have significant limitations: Virtual Reality: Often fails to accurately replicate complex tool-tissue interactions Animal Models: High costs, anatomical differences, and ethically problematic Silicone Models: While accessible and low-cost, they are often noted to be stiffer and more tear-resistant than real human tissue Hydrogel models represent a high-fidelity "bridge" between digital simulation and the operating room, offering realistic tissue responsiveness without the ethical or logistical drawbacks of animal tissue 2. Research Objectives Anatomical Design: Utilize patient-specific imaging data (CT/MRI) to create a scale model of an infant's kidney and dilated renal pelvis Fabrication: Use 3D printing to create negative-volume molds for casting hydrogel organs with realistic haptic properties. Validation: Conduct face, content, and construct validation to ensure the model distinguishes between expert and novice surgeons while providing genuine educational value 3. Methodology (Step-by-Step for the Student) Image Segmentation: Use software (e.g., 3D Slicer) to segment the renal anatomy from anonymized paediatric scans, ensuring the model reflects the small working spaces of an infant 3D Mold Design: Using CAD software, design negative-volume molds for the kidney, dilated pelvis, and ureter Prototyping: Print the molds using a high-resolution 3D printer. The student will experiment with hydrogel compositions to match the delicate "feel" and "stretch" of neonatal tissue Model Assembly: Integrate the hydrogel organs into a infant mannequin torso with simulated restricted operative view Simulation Trials: Participants will perform a robot-assisted or laparoscopic dismembered pyeloplasty—including dismemberment, spatulation, and anastomosis. Validation Metrics: Collect data using 5-point Likert scales for realism and use objective metrics such as GEARS scores, procedure time, and flow-rate patency tests to validate the model 4. Expected Outcomes for the Student Technical Mastery: Proficiency in 3D medical segmentation, CAD design, and advanced 3D printing Robotic Skills: Direct experience with the Da Vinci console and surgical performance analytics (e.g., economy of motion and master workspace) Research Impact: Contribution to a validated, high-fidelity training solution that fills the gap for procedure-specific paediatric models This project offers a unique opportunity to work at the cutting edge of biofabrication and surgical education, ultimately aiming to improve patient safety and surgical outcomes at Monash Children's Hospital and internationally.