Purpose: Compare the changes in the geniohyoid muscle before and after orthognathic surgery. Methods: Ninety patients with jaw deformities who underwent orthognathic surgery, including sagittal split ramus osteotomy (SSRO), were included. Computed tomography (CT) and cephalometric analyses were performed before and 1 year after surgery. Changes in the position of the hyoid bone (H) were measured using cephalometric analysis. Computed tomography images were reconstructed using ProPlan CMF (Materialize), and the length, height, cross-sectional area, and CT values of the geniohyoid muscle were measured before and 1 year after surgery. Results: In comparisons between preoperation and 1 year postoperation in the female SSRO advance group, the postoperative value was significantly larger than the preoperative value in the geniohyoid area ( P = 0.020), length ( P = 0.047), and CT value ( P = 0.007). Conclusion: This study suggested that the morphology of the geniohyoid muscle varies with orthognathic surgery, including SSRO, which affects the CT values.
Kohara et al. (Mon,) studied this question.