Impact On The Upper Airway Space Of Different Types Of Orthognathic Surgery For The Correction Of Skeletal Class Ⅲ Malocclusion: A Meta-analysis

ObjectiveThis study is aimed at assembling,through a meta-analysis,scientific evidence related to the effects of isolated mandibular setback(Md S)surgery and maxillary LefortⅠosteotomy advancement surgery combined with mandibular setback surgery(Md S+Mx A)for the correction of Class Ⅲ malocclusion on the cross-sectional area(CSA)and volume of the upper airway as assessed using CT.MethodsAn electronic search was conducted on Cochrane Library,EMBASE,Pub Med,Scopus,Web of Science,CNKI and Wanfang databases up to June 20,2016.The inclusion criteria were clinical human studies,including prospective and retrospective studies,with the aim of comparing the impact on the upper airway space of different types of orthognathic surgery for the treatment of the skeletal class Ⅲ malocclusion.The methodological index for non-randomized studies(MINORS)was chosen as the evaluation instrument,Revman 5.3 and Stata 12.0 was used for the meta-analysis.ResultsA total of 1213 studies were retrieved,of which only 18 met the eligibility criteria,6 studies were prospective and 12 studies were retrospective.Respectively compared the effect of Md S(8 studies)and Md S+Mx A(14 studies)for the correction of Class Ⅲ malocclusion on the upper airway volume.Compared the effect of one-jaw surgery and two-jaw surgery on the PNS-CSA(4 studies)、SP-CSA(6 studies)、EP-CSA(6 studies)、nasopharynx volume(4 studies)、oropharynx volume(4 studies)、hypopharynx volume(3 studies)、upper airway total volume(4 studies).The results of meta-analysis showed that the mean decrease in the upper airway volume after isolated mandibular setback surgery was 3.24 cm3 [95%CI(-5.25,-1.23),p =0.002];the mean decrease in upper airway volume after Md S+Mx A surgery was 0.86 cm3[95%CI(-2.19,-0.47),p =0.21];comparison between one-jaw surgery and two-jaw surgery showed significant differences in the CSA of the posterior nasal spine plane(PNS)and epiglottis plane(EP),whereas no significant differences existed in the CSA of soft palate plane(SP);the difference of nasopharynx volume(WMD=-1.40,95%CI= [-2.10,-0.71 ],p<0.0001),upper airway total volume(WMD=-3.41,95%CI=[-5.59,-1.24],p=0.002)showed statistical significant between one-jaw surgery and two-jaw surgery,the difference of oropharynx volume(WMD=-0.99,95%CI= [-2.09,0.12 ],p=0.08),hypopharynx volume(WMD=-0.38,95%CI=[-1.95,1.20],p=0.64)had no statistical significant.ConclusionThe upper airway volumes respectively decrease 3.24cm3 and 0.86cm3 after isolated mandibular setback surgery and two-jaw surgery.Compared with isolated mandibular setback surgery,maxillary LefortⅠosteotomy advancement surgery combined with mandibular setback surgery has slighter effects on PNS-CSA,EP-CSA,nasopharynx volume and upper airway total volume.The results of this study suggest that bimaxillary surgery promotes less decrease on the upper airway than mandibular setback surgery alone for the correction of the skeletal class Ⅲ malocclusion,two-jaw surgery is superior to one-jaw surgery,especially for those with potential breathing problems.Orthodontic and orthognathic surgeons should assess preoperative and postoperative changes in the airway so as to prevent excessive airway stenosis and avoid the development of iatrogenic OSA.Due to the constraints of quality and quantity of literature,the conclusion still needs to be verified and tested by future clinical trials of higher quality and larger size.