Three-dimensional (3D) printing technology has been utilized to create patient-specific (PS) replicas as visual aids for surgical planning.<sup>1Schmauss D, Gerber N, Sodian R Three-dimensional printing of models for surgical planning in patients with primary cardiac tumors J Thorac Cardiovasc Surg 2013 ;  145 : 1407-140810.1016/j.jtcvs.2012.12.030 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 2Schmauss D, Juchem G, Weber S, e al. Three-dimensional printing for perioperative planning of complex aortic arch surgery Ann Thorac Surg 2014 ;  97 : 2160-216310.1016/j.athoracsur.2014.02.011 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 3Komai Y, Sakai Y, Gotohda N, e al. A novel 3-dimensional image analysis system for case-specic kidney anatomy and surgical simulation to facilitate clampless partial nephrectomy UROLOGY 2014 ;  83 : 500e507

Cliccare qui per andare alla sezione Riferimenti, 4Silberstein JL, Maddox MM, Dorsey P, e al. Physical models of renal malignancies using standard cross-sectional imaging and 3-dimensional printers: a pilot study UROLOGY 2014 ;  84 : 268e273

Cliccare qui per andare alla sezione Riferimenti</sup> However, they cannot recreate the operative experience due to a lack of realistic tissue characteristics.

Develop anatomically accurate, realistic, PS partial nephrectomy platforms suitable for pre-operative surgical rehearsals using 3D-printing and hydrogel casting.

Patient CT scans were segmented into a computer-aided design (CAD) file and used to create injection casts. Kidney and tumor casts along with hollow vascular and urinary structures were 3D-printed. The hilar structures and tumor were registered into the kidney cast, injected with poly-vinyl alcohol (PVA) hydrogel, and processed to create the kidney phantom. Mechanical and functional testing protocols were completed to confirm that the properties of PVA matched the live tissue.<sup>5Melnyk R, Ezzat B, Belfast E, e al. Mechanical and functional validation of a perfused, robot-assisted partial nephrectomy simulation platform using a combination of 3D printing and hydrogel casting World J Urol 2020 ;  38 : 1631-1634 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> 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.

The 7%-3freeze/thaw PVA best recreated the mechanical and functional properties of porcine kidneys, 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.

This reproducible method shows high anatomical accuracy, realistic tissue properties, and translational effects between rehearsals and live surgery. To determine the effects on patient outcomes, future studies will compare the impact of completing a pre-operative rehearsal vs standard surgical preparation.