Are we ready for virtually planned, 3D printed titanium plates for zygoma fractures? – A feasibility study of 16 post-mortem fractures

The state-of-the-art approach to open reduction and fixation (ORIF) of zygoma fracture fragments is based on manual skills. Achieving high accuracy can be challenging. Our feasibility study on deceased body donors with artificial zygomatic fractures investigated whether virtual repositioning of the fractures and the use of customised 3D-printed titanium osteosynthesis plates was similar in accuracy to the conventional manual procedure, and whether the method was applicable in a clinical setting. The accuracy of the different workflows was evaluated. Eight cadaver skulls from the body donation program of Kiel University, with 16 zygomatic bones, were scanned using cone-beam computed tomography before and after artificial fracturing. Virtual reconstruction of the skull was performed and 3D-printed, individualized titanium plates were used to fix the bone fragments. Using a postoperative CBCT scan, the deviation of bone fragments from the original position was detected and the accuracy of the planning was measured within a 3D coordinate system using algorithmically matched reference points. The statistical analysis was performed with SPSS, applying paired and unpaired t-tests. Although the virtual planning demonstrated some imprecision (p = 0.002), this did not lead to postoperative inaccuracies. There was a positive correlation between the degree of dislocation of the fractures and postoperative inaccuracy if regular plates were used (p = 0.02). This was not the case when 3D-printed plates were used, suggesting that 3D-printed plates offer an advantage in heavily dislocated fractures. The workflow to implement 3D-printed titanium plates for trauma cases seems to be applicable to clinical routine. In this study using a limited number of cheek bones, most of which were not heavily dislocated, 3D-printed plates were similar in accuracy to regular plates. The possible advantages for heavily dislocated fractures need further investigation.