Accuracy of maxillary positioning in semi-guided orthognathic surgery using 3D-printed cutting guides and bending plates: A retrospective study

Additively manufactured interocclusal splints and patient-specific implants (PSI) are well-established methods for transferring virtual planning in orthognathic surgery. However, both methods entail specific limitations in terms of time and cost efficiency. This retrospective study evaluated the accuracy of maxillary positioning using a novel semi-guided workflow based on patient-specific cutting guides and pre-bent fixation plates. Nineteen patients who underwent bimaxillary orthognathic surgery with Le Fort I osteotomy at the University Hospital Basel between 2023 and 2025 were included. Pre- and postoperative CT or CBCT imaging in combination with virtual surgical planning (VSP) data were analysed to assess maxillary and mandibular positional deviations, osteotomy accuracy, and operative time. The newly described semi-guided workflow demonstrated a high osteotomy precision, with deviations ranging from 0.09 to 1.34 mm and a mean deviation of 0.56 mm. Overall, maxillary positioning showed no statistically significant intergroup differences compared to the conventional splint-based workflow. A significant difference of limited clinical relevance was found only for absolute vertical maxillary deviation, which was greater in the semi-guided group. In addition, mean operative time was 28.8 min shorter (p = 0.173) in the semi-guided group. These preliminary findings suggest that semi-guided orthognathic surgery can transfer the VSP with deviations within the range observed for the conventional splint-based workflow. The described hybrid workflow may therefore represent a clinically promising alternative to conventional splint-based workflows and fully patient-specific implant-based approaches in orthognathic surgery.