Changes in lateral standing posture following orthognathic surgery: a cohort study

Abstract

Altering neuromuscular and musculoskeletal relationships also affects standing body posture, particularly in the head and neck areas. This prospective cohort study assessed the effects of orthognathic surgery on head posture in the lateral standing view. Thirty-one patients who underwent single-jaw orthognathic mandibular surgery were included. The patients underwent lateral cephalometric and photographic evaluations of their natural habitual posture before and 6 months after surgery. The craniovertebral angle and Frankfort angle (Frankfort horizontal line to true horizontal line angle) were determined and measured using MB-Ruler software. Mandibular positional changes were also measured by superimposing lateral cephalograms and recording changes in the menton point in the vertical and horizontal planes. All data were analysed by paired t-test. The craniovertebral angle increased significantly in patients with Class II malocclusion (P = 0.001) and decreased significantly in Class III patients (P = 0.004). Furthermore, the Frankfort angle was significantly increased in both Class II (P = 0.005) and Class III (P = 0.012) patients. The tendency towards forward head posture decreased in patients with Class II malocclusion, and the lateral neck posture improved. Conversely, a slight but significant tendency towards a forward head posture was observed in Class III patients after surgery. Furthermore, the natural head position changed in both study groups, leading to a more upright head posture.