Pharyngeal airway space and hyoid bone positioning after different orthognathic surgeries in skeletal Class II patients

Publication date: Available online 6 March 2017
Source:Journal of Oral and Maxillofacial Surgery
Author(s): Chunmiao Jiang, Yating Yi, Chunxiao Jiang, Shanbao Fang, Jun Wang
PurposeTo obtain good profiles, severe skeletal Class II malocclusion patients require orthognathic surgery, which might change their airway space and consequently influence their quality of sleep. Here, we aimed to 1) determine the effect of different orthognathic surgeries on pharyngeal airway space and hyoid bone position in skeletal Class II patients and 2) evaluate the stability of changes in the pharyngeal airway space and hyoid bone position after orthognathic surgeries.Patients and MethodsSevere skeletal Class II patients who had undergone mandibular advancement (MA) or mandibular advancement & maxillary setback (MAMS), were included in this retrospective cohort study. Changes in the pharyngeal airway space and hyoid bone position were evaluated as the primary outcome variables. Measurements were obtained before surgery (T1), one month after surgery (T2), and two years after surgery (T3) using Dophin Imaging Software version 11.0. Differences in measurements between T2 and T1, and T3 and T1 were calculated and imported into SPSS software for data analysis.ResultsIn this study, 50 patients were included, with 25 patients in the MA group and 25 patients in the MAMS group. The oropharyngeal and hypopharyngeal airway cross-dimensions and areas were significantly increased in the MA group (P<0.05), and the increases were stable at T3. In the MAMS group, the nasopharyngeal airway cross-dimension and area were decreased (P>0.05), but the hypopharyngeal cross-dimension and area were significantly increased (P<0.05). The hyoid bone moved superiorly and forward after surgery in the MA group (P<0.05), and the movement was stable at T3.ConclusionsMandibular advancement can widen the oropharyngeal and hypopharyngeal airway space, while maxillary setback can narrow the nasopharyngeal airway space. Some relapse related to the width of oropharynx and hypopharynx was found in the long-term observation. The hyoid bone moved superiorly and forward in the MA group.



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