Urology Video Journal (Mar 2023)
The development & implementation of a 3D printing perfused hydrogel Robotic Assisted Partial Nephrectomy Surgical Training Platform: Advancing from generic to patient specific simulation-based translational research
Abstract
Background: Robot-assisted partial nephrectomy (RAPN) is becoming the standard treatment for small renal masses. However, the availability of realistic validated, non-biohazardous procedural platform for training are lacking for both generic and patient-specific training. Objective: The multi-institutional validation of a high-fidelity, perfused, inanimate, simulation platform for RAPN utilizing incorporated clinically relevant objective metrics of simulation (CROMS) applying modern validity standards. This concept was further developed into patient specific models for surgical rehearsals by converting patients axial imaging using image segmentation, mechanical testing of hydrogel components to realistically replicate the properties of live tissue and anatomical verification of models to patients’ original scans. Materials and Methods: Utilizing a combination of 3D printing and hydrogel casting a RAPN model was developed from a patient's C.T. scan with a 4.2 cm, upper-pole renal tumor (RENAL nephrometry score 7x). 3D-printed casts designed from the patient's imaging were utilized to fabricate and register hydrogel (Polyvinyl alcohol) components of the kidney including vascular and pelvicalyceal systems. Following mechanical and anatomical verification of the kidney phantom, it was surrounded by other relevant hydrogel organs and placed in a laparoscopic trainer. 27 novice and 16 expert urologists categorized according to caseload, from 5 academic institutions completed the simulation. Mechanical and functional testing protocols were completed to confirm that the properties of PVA matched the live tissue.5 Anatomical accuracy was confirmed by CT scanning the phantom and creating another CAD, which was compared to the original patient CAD. Full-procedural PS rehearsals were completed 24-48 hours prior to their respective live surgeries. Clinically relevant metrics (warm ischemia time, estimated blood loss, and positive surgical margins) from each rehearsal and live case were compared using a Wilcoxon-rank sum test. Results: Expert ratings demonstrated model’s superiority to other procedural simulations in replicating procedural steps, bleeding, tissue texture, and appearance. Significant difference between groups was demonstrated in CROMS [console time (p < 0.001), warm ischemia time (p < 0.001), estimated blood loss (p < 0.001)] and GEARS (p < 0.001). Six major intraoperative complications occurred only in novice simulations. GEARS scores highly correlated with the CROMS. The 7%-3freeze/thaw PVA best recreated the mechanical and functional properties of porcine kid- neys, while anatomical verification showed ≤1 mm deviation of the kidney and tumor from the patient anatomy and ≤ 3 mm for the hilar structures. PS rehearsal platforms were fabricated using these methods for 8 patients (average tumor size 5.92 cm and nephrometry score 9.8). A positive correlation was found for warm ischemia time and estimated blood loss between rehearsals and live surgeries. Conclusions: This perfused, procedural model offers an unprecedented realistic simulation platform which incorporates objective, clinically relevant, and procedure-specific performance metrics. Furthermore, this reproducible method shows high anatomical accuracy, realistic tissue properties, and translational effects between rehearsals and live surgery.
