Measurement of the Accuracy of 3D-Printed Medical Models to Be Used for Robot-Assisted Partial Nephrectomy

OBJECTIVE. Three-dimensional printing is being used for surgical assistance, particularly for robot-assisted partial nephrectomy (RAPN). The objective of this study was to assess the anatomic accuracy of the 3D model used for 3D model-guided RAPN. SUBJECTS AND METHODS. The study included patients who underwent RAPN aided by 3D printing and anonymized CT. The model, based on preoperative CT with specialized software and a 3D printer, included vascular, urinary, parenchymal, and tumoral elements. It was then scanned. The major axis of the kidney and tumor and the volume of the tumor were measured blindly on the preoperative CT scan and the CT scan of the 3D model. Three comparative measurements between arterial branches were performed for each patient. The correlation of the arterial distribution between the scanner and the 3D model was evaluated on a Likert scale. RESULTS. A total of 16 patients were included between December 2017 and March 2018. The median tumor size was 4.7 cm (interquartile range [IQR], 3.9-6.5 cm). Between the initial CT scan and the 3D printed kidney, the major renal axis varied a median of 1.8% (IQR, 0.8-4.23%), major tumor axis varied 2.35% (IQR, 0.45-8.6%), and the tumor volume varied 14.7% (IQR, 11.5-25.2%). The median arterial interbranch measurement (three measurements performed on each kidney) was 1.8% (IQR, 1-3.25%). Fourteen of 16 (87.5%) 3D printed models had a score of 4 or higher by two readers and were considered valid. CONCLUSION. Three-dimensional printed models are accurate with respect to anatomic reality. The reliability of surgical assistance with 3D printed models must be evaluated.