Clinical Study On Movement Of Midface Bone And Change Of Upper Airway In Patients With Crouzon Syndrome After Le Fort Ⅲ Distraction Osteogenesis

Objective:To analyze the clinical effects of Le Fort Ⅲ distraction osteogenesis(DO)for Crouzon patients to treat midfacial dysplasia,solve sleep apnea distress and improve sleep hypoxemia.To study the relationship between movement of midface bones and change of upper airway meanwhile find the correlation between them.Methods:The subjects of the study were 7 children with Crouzon syndrome(age:4-18)who were treated in our department from March 2014 to August 2018.According to our treatment strategy,all children took Le Fort Ⅲ DO.Monitoring OSAS reports and the situations of sleep hypoxemia to perform comparative analysis of the clinical effects before and after the operation.Using three-dimensional CT to reconstruct upper airway and facial bones.The upper airway was divided into four parts:nasal cavity,nasopharynx,velopharynx,oropharynx.Paired sample T test method was used to analyze the changes of upper airway,four divided airways and bones in midface,and the PEARSON test was used to evaluate the correlation between airway changes and bone movement.Results:The symptoms of all patients were significantly improved including sleep apnea syndrome and hypoxemia;the total volume of upper airway increased by 50.0%(p=0.02)after Le Fort Ⅲ DO;the change in nasopharynx is about 416.1%(p=0.016);the SNA angle increased 27.7%(p<0.001);the SNB angle increased 4.7%(p=0.015),the change of A-CP was about 30%(p<0.001);the change of B-CP was about 10.9%(p=0.001);the change of T-CP was about 47.9%(p=0.016);the change of E-CP was about 61.9%(p=0.009);the change of SP-CP was about 61.6%(p=0.01);the change of PNS-CP was about 32.2%(p=0.042);the change of SP-FHP decreased 9.6%(p=0.034);the angle of MP and FHP decreased 13.7%(p=0.035).Conclusion:Le Fort Ⅲ DO can significantly treat OSAS and hypoxemia,move the midface bone forward,effectively expand the volume of upper airway and nasopharynx,then improve the ventilation function in Crouzon patients.However,there was no significant change in nasal cavity,velopharynx and oropharynx.No significant correlation was found between the movement of the midface bones and the change of airway.