唇腭裂上颌复合体在不同类型上颌截骨内置式牵引下生物力学研究

Biomechanical study of internal midface distraction after different types of maxillary osteotomy in patients with deft lip and palate

目的探讨唇腭裂继发上颌发育不全应用不同类型截骨内置式牵引的生物力学变化特点。方法采用三维有限元方法，建立唇腭裂上颌复合体Le FortⅠ、Ⅱ、Ⅲ型截骨骨块及相应软组织有限元模型，分别模拟临床上新型内置牵引方式，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情况。结果唇腭裂上颌复合体不同类型截骨内置式牵引下，Le Fort Ⅰ型截骨腭部出现压缩现象，而Le Fort Ⅱ、Ⅲ型截骨腭部压缩现象不明显。矢向位移比较，Le FortⅢ型截骨内置式牵引可以整体前移截骨体，Le FortⅠ、Ⅱ型截骨存在不同程度的旋转。垂直向位移比较Le FortⅡ型截骨出现较多的逆向旋转。结论三维有限元仿真研究应用于内置式牵引成骨手术，可以较好地反映颌骨位移情况，为手术计划提供理论依据。

Objective To investigate the biomeehanieal changes of internal midfaee distraction after different types of maxillary osteotomy in patients with cleft lip and palate（CLP）. Methods 3-D finite element （FEM） analysis was used. 3-D models of Le Fort Ⅰ , Ⅱ , Ⅲ osteotomy and soft tissue were established. Based on the new pattern of internal midface distractor, the distraction of maxillary complex was simulated to advance 10mm anteriorly. The mechanical change was studied. Results The maxillary complex in CLP were advanced after distraction. Constriction of alveolar crest and palate occurred in Le Fort 1- osteotomy, but not in Le Fort H and Ⅲ osteotomy. The maxillary complex was moved anteriorly en bloc after Le Fort Ⅲ osteotomy, but some degree of rotation of maxillary complex was observed during the distraction after Le Fort Ⅰ and Ⅱ osteotomy. In vertical direction, the maxillary complex had more counterclockwise rotation after Le Fort Ⅱ osteotomy. Conclusion 3-D FEM analysis can be used for the study of internal distraction. It can reflect the maxillary movement and provide the theory basis for preoperative design.