Personalized Renal Collecting System Mockup for Procedural Training Under Ultrasound Guidance.

Objective: In recent years, there has been increasing interest in the use of ultrasound guidance for endoscopic and percutaneous procedures. Kidney mockups could be used for training, however, available mockups are normally incompatible with ultrasound imaging. We developed a reproducible method to manufacture an ultrasound-compatible collecting system mockup that can be made at urology laboratories. Methods: Positive and negative molding methods were used. A three-dimensional (3D) digital model of a urinary collecting system and the overlying skin surface were segmented from computed tomography. A containment mold (negative) was made following the shape of the skin surface using 3D printing. A collecting system mold (positive) was also 3D printed, but made of a dissolvable material. The containment mold was filled with a gelatin formula with the collecting system mold submersed in situ within. After the gelatin solidified, a solution was used to dissolve the collecting system mold, but not the gelatin, leaving a cavity with the shape of the collecting system. The gelatin was extracted from the container mockup and the collecting system cavity was filled with water. The mockup was imaged with ultrasound to assess echogenicity and suitability for simulating ultrasound-guided procedures. Results: A clear shape corresponding to the collecting system was observed inside the gel structure. Structural integrity was maintained with no observable manufacturing marks or separation seams. Ultrasound images of the mockup demonstrated clear differentiation at the gelatin/water interface. A mock stone was placed in the collecting system and needle targeted to simulate percutaneous needle access. Conclusion: We developed a simple method to manufacture a personalized mockup of the renal collecting system of a patient that can be used for ultrasound-guided percutaneous needle access. Generic collecting system mockups can be used for training, and patient-specific models can be used to simulate and decide the best access path before a clinical case.