Three-Dimensional Morphological Changes of the Upper Airway in Patients With Skeletal Class III Malocclusion After Orthognathic Surgery

Objective: To evaluate the morphological changes of the upper airway of patients with skeletal Class III malocclusion after undergoing bilateral mandibular ramus dislocated mandibular retrogression (SSRO) or SSRO combined with Le Fort I maxillary osteotomy and 3-dimensional imaging. Methods: All previous studies related to the upper airway in patients with skeletal class III malocclusion and orthognathic surgery were collected from the PubMed, EMB, Cochrane Library, Web of science, ClinicalKey, EBSCO, Weipu, Wanfang, China National Knowledge Infrastructure, and Chinese BioMedical Literature databases. The search date ends in August 2017. RevMan5.3 software was used to perform a meta-analysis related to upper airway morphology. Ten studies were included. Results: The meta-analysis showed that 6 months after SSRO, CV1, and CV2 did not change significantly (P >0.05), whereas CV3 and CV4 narrowed (P <0.05) and remained narrow after 1 year (P <0.05). (CV1,CV2,CV3,CV4: Plans parallel to the FH plane passing through the most anterior inferior point of the anterior arch of the atlas, the 2nd cervical vertebra, the 3rd cervical vertebra, the 4th cervical vertebra.) There was no significant change in nasopharyngeal volume or laryngeal pharyngeal volume (P >0.05), but oropharyngeal volume and total volume decreased (P <= 0.01). Six months after SSRO combined with Le Fort I maxillary osteotomy, the minimum cross-sectional area of the upper airway was smaller (P <0.05), there was no significant change in nasopharyngeal volume or oropharyngeal volume (P >0.05), and oropharynx volume and total volume decreased (P <0.05). Conclusions: Single and double jaw surgery has no significant effect on nasopharynx and oropharynx, but reduces laryngopharynx and total volume; however, whether this will result in postoperative obstructive sleep apnea-hypopnea syndrome or become ameliorated over time requires more in-depth study and a longer period of clinical observation.