Three-Dimensional Hemisided Analysis of the Pharyngeal Airway: A Novel Technical Strategy to Evaluate Asymmetric Remodeling After Orthognathic Surgery

Orthognathic surgery for asymmetric mandibular prognathism may induce side-specific alterations in the pharyngeal airway, yet conventional analyses are limited to global assessments. This technical report introduces a reproducible method for three-dimensional (3D) hemisided airway analysis to investigate these nuanced changes. This retrospective study included 5 patients with asymmetric mandibular prognathism who underwent a hybrid technique combining modified intraoral vertico-sagittal ramus osteotomy (mIVSRO) on one side and sagittal split ramus osteotomy (SSRO) on the other. Preoperative and postoperative cone-beam computed tomography scans were used for 3D airway segmentation. Following registration to a standardized craniofacial coordinate system, the airway models were partitioned into hemisides for independent volumetric and morphometric analysis. An Asymmetry Index (AI) was calculated to quantify changes. The analytical workflow demonstrated excellent intra-rater reliability (ICC>0.98). Following a mean pogonion setback of 6.3 mm, the total airway volume decreased by an average of 14.3%, consistent with established literature. The novel hemisided analysis proved sufficiently sensitive to detect side-specific changes, revealing highly individualized and variable responses in airway asymmetry postoperatively. The change in AI for hemi-airway volume varied among patients, suggesting a differential influence of the mIVSRO and SSRO techniques on the surrounding soft tissues. This study presents a feasible and reliable technical strategy for 3D hemisided pharyngeal airway analysis. This granular analytical framework provides a validated tool for future investigations into the asymmetric effects of different osteotomy techniques. Ultimately, this methodology may inform surgical planning by enabling the optimization of airway morphology in complex asymmetric deformities.