Three-dimensional accuracy of mandibular reconstruction by patient-specific pre-bent reconstruction plates using an “in-house” 3D-printer

Purpose The purpose of this study was to compare the three-dimensional accuracy of mandibular reconstruction following mandible continuity resection in patients treated with patient-specific, pre-bent reconstruction plates, using an ‘in-house’ 3D printer, with that in patients treated with conventional, intraoperatively bent plates. Patients and methods We retrospectively analyzed 42 alloplastic mandibular reconstructions following continuity resection. 21 patients received patient-specific, pre-bent reconstruction plates using an in-house 3D printer. The control group consisted of 21 patients provided with intraoperatively bent reconstruction plates. Distances between corresponding anatomical landmarks on the mandibular angle and condyle (A–A′, BB′, CC′, BC′), as well as the intercondylar angle (ICA), were measured and compared on the pre- and postoperative CT scans. Results Multivariate analysis of variance (MANOVA) showed significant multivariate main effect of group (F(5, 36) = 5.58, p = 0.001; Wilks lambda 0.564; partial η2 = 0.436), indicating more accurate postoperative results for the pre-bent group. Post-hoc comparison revealed significantly larger postoperative deviation in the distances between the mandibular angle and the intercondylar angle (ICA) for the intraoperatively bent group in comparison with the pre-bent group. However, there was no significant effect on the distance between the condyles. Conclusions Mandibular reconstructions employing patient-specific, pre-bent reconstruction plates made using an in-house 3D printer show significantly better three-dimensional accuracy compared with intraoperatively bent plates. The described method prevents rotational error of the mandibular angle and improves restoration of the physiological intercondylar angle in mandible reconstruction after continuity resection.