In orthognathic surgery, patient-specific osteosynthesis implants (PSIs) represent a novel approach for the reproduction of the virtual surgical planning on the patient.
The aim of this study is to analyse the quality of maxillo-mandibular positioning using a hybrid mandible-first mandibular-PSI guided procedure on twenty-two patients while the upper maxilla was fixed using manually-bent stock titanium miniplates. The virtual surgical plan was used to guide the design of PSIs and positioning guides, which were then 3D printed using biocompatible materials.
A CBCT scan was performed one month after surgery and postoperative facial skeletal models were segmented for comparison against the surgical plan. A three-dimensional cephalometric analysis was carried out on both planned and obtained anatomies. A Spearman correlation matrix was computed on the calculated discrepancies, in order to achieve a more comprehensive description of maxillo-mandibular displacement.
Intraoperatively, all PSIs were successfully applied. The procedure was found to be accurate in planned maxillo-mandibular positioning reproduction, while maintaining a degree of flexibility to allow for aesthetics-based verticality correction in a pitch range between-5.31 and +1.79 mm. Such correction did not significantly affect the achievement of planned frontal symmetry.