半侧颜面短小畸形咬肌方向及机械效益的研究

Study on orientation and mechanical advantage of masseter muscle in hemifacial microsomia deformities

目的探讨半侧颜面短小畸形(hemifacialmicrosomia,HFM)患者双侧咬肌方向及机械效益的差异。方法自2010—2019年,中国医学科学院北京协和医学院整形外科医院颌面整形中心收集23例未经治疗且单侧受累患者的CT数据,输入MIMICs 17.0软件进行三维重建,测量咬肌在矢状面和冠状面的方向角α和β,并计算其机械效益,采用配对t检验比较患侧与健侧的差异。结果HFM PruzanskyⅡb型患者患侧咬肌倾斜角α小于健侧(P<0.05),HFMⅠ型和Ⅱa型患者患侧咬肌机械效益小于健侧(P<0.01)。结论HFMⅡb患者患侧咬肌在矢状面上相对健侧更加前倾,HFM双侧咬肌机械效益的差异可能与咬力的不对称有关。

Objective To explore the differences of orientation and mechanical advantage of masseter muscle between intact side and affected side in patients with hemifacial microsomia(HFM).Methods From 2010 to 2019,the data of CT scan of 23 patients with HFM deformity was collected.The data were input into MIMICS 17.0 software for three-dimensional reconstruction.The orientation angleαandβin the sagittal plane and coronal plane of masseter muscle was measured and the mechanical advantage was calculated.The differences between intact side and affected side were compared by paired t-test.Results In patientswith type PruzanskyⅡb,theαangle in the sagittal plane of the affected side was smaller than that of the intact side(P<0.05).In patients with type HFMⅠandⅡa,the mechanical advantage of masseter muscle of the affected side was smaller than that of the intact side(P<0.01).Conclusion In patients with HFM typeⅡb,the masseter muscle of the affected sideshowed a more forward-directed orientation than the intact sidein the sagittal plane.The differences of mechanical advantagemay correlate with uneven distribution of bite force between the affected side and intact side.