牙槽嵴裂隙间固定对腭裂上颌复合体内置式牵引成骨生物力学的影响

Three-dimensional finite element analysis for internal maxillary distraction with fixation between cleftpalate

目的探讨裂隙间固定对唇腭裂上颌复合体牵引成骨生物力学的影响。方法采用三维有限元方法，建立唇腭裂上颌复合体LeFortⅠ型截骨骨块及相应软组织有限元模型，在保留牙槽嵴裂隙与裂隙两侧钛板固定两种情况下，模拟临床上内置式牵引方式，使截骨块上牵引器固位点沿牵引方向前移10mm，比较分析其生物力学变化。结果唇腭裂上颌复合体LeFortⅠ型截骨内置式牵引下，腭部出现压缩现象，而裂隙两侧钛板固定腭部压缩现象不明显。矢向位移与垂直向位移在两种工况下比较，位移方向及大小与保留裂隙的前牵引无明显差异。结论裂隙间固定后唇腭裂上颌复合体内置式牵引成骨，可以避免腭部出现压缩现象，有生物力学指导意义。

Objective To investigate the biomechanical changes of internal maxillary distraction with fixation between cleft palate. Methods Three-dimensional FEM models of I.eFort I osteotomy and soft tissue in CLP maxillary complex were established. Two different conditions were simulated： one was the cleft palate connected by a titanium plate, and the other was the cleft retained. Internal midface distraction which applied in clinic were simulated. Fixation points of the distraction devices on the LeFort I osteotomy complex were advanced by 10 mm in the direction of frontage. Biomechanical changes for different conditions were investigated by means of finite element analyses. Results LeFort I osteotomy of maxillary complex area in CLP was advanced. Constrictions occurred in alveolar crest and palate, when the cleft was retained. Constriction of alveolar crest and palate was not obvious, when the cleft palate was connected by a titanium plate. There were no differences between sagittal and vertical displacement to internal distraction in LeFort I osteotomy. Clockwise rotation occurred in vertical direction. Conclusions Internal maxillary distraction with fixation between cleft palate could avoid constriction of alveolar crest and palate. It provides the options and reference to the surgi- cal plans.