How to obtain a 3D printed model of renal cell carcinoma (RCC) with venous tumor thrombus extension (VTE) for surgical simulation (phase I NCT03738488).

This is the phase 1 of a multicenter clinical trial (NCT03738488), which aims to assess the efficacy and efficiency of surgery planning with 3D models of renal cell carcinoma (RCC) with venous tumor thrombus extension (VTE) compared to the standard images (CT). The objective of this phase is to obtain a 3D printed model of RCC with VTE that is feasible, accurate, reproducible, suitable for surgical simulation, and affordable. A specific protocol was developed to obtain the computed tomography (CT) image: early arterial and nephrogenic phase. ITK-snap® and VirSSPA Software® were used to segment the areas of interest. The resulting 3D mesh was processed with MeshMixer® and Cura®. Ten models from seven different cases were segmented and printed using different 3D printers and materials. We evaluated the material, scale, wall thickness, anatomy printed, 3D conformation, accuracy compared to the CT, suitability to perform the surgery, material, cost, and time (segmentation + design + fabrication + finishing). The four selected models were printed with a BQ Witbox FDM printer in polyurethane filament with a 0.8 mm wall thickness and 100% scale. All the relevant anatomical structures could be correctly identified, the 3D conformation was maintained with good accuracy compared to the CT and the surgery could be performed on them. Mean design time, model cost and printing time were 8.3 h, 33.4 €, and 38.5 h respectively. Various feasible 3D models of RCC with VTE were obtained after a few attempts. The final models were proved to be reproducible, accurate compared to the CT, and suitable for surgery simulation. The printing process was standardized making it possible to manufacture affordable 3D printed models.