Changes in bone microstructural characteristics and the position of condyle head after orthognathic surgery with or without condylar resorption

Abstract

Abstract Condylar resorption occurs in some cases after orthognathic surgery, and the risk factors associated with postoperative condylar head resorption have been extensively described. Nevertheless, even in cases with a combination of risk factors, postoperative condylar resorption may not appear. This study analyzed the microstructure and three-dimensional positional change of the condylar bone via imaging in patients who have undergone bimaxillary orthognathic surgery to determine whether the microstructure differs between patients with and without postoperative condylar resorption. Among asymptomatic patients who underwent bimaxillary surgery between April 2021 and March 2022 at our department, the bone microstructure of 17 patients was analyzed, limited to “female,” “skeletal Class II,” and “high-angle cases,” which are known risk factors for mandibular head resorption. Multidetector computed tomography was performed on these patients before and 6 months after surgery, and the bone microstructure of the condylar head was compared with the three-dimensional positional changes of the condylar bone and the proximal bony fragments according to whether the condylar head was resorbed after surgery using the bone morphology software TRI/3D-BON. Patients with condylar bone abnormalities before surgery and those with high trabecular bone density can develop postoperative resorption if the condyle is misaligned during surgery.