计算机辅助模拟偏突颌患者颏部不对称与成形术的相关性研究

Correlated relationship between the genial asymmetry and genioplasty of computer-aided simulated laerognathism patients

目的 应用计算机辅助外科模拟软件重建偏突颌畸患者的三维头颅模型,研究颏部不对称程度与矢状劈开截骨是否同期行水平向颏成形术之间的联系,得出水平向行颏成形术参考指标.方法 对40例偏突颌畸形患者行回顾性研究.A组20例行单颌矢状劈开截骨同期行水平向颏成形术;B组20例单纯行单颌矢状劈开截骨,根据患者术前的扫描数据,重建三维头颅模型,并确立下颌牙合平面：①测量双侧下颌第一磨牙颊沟相对上颌第一磨牙近中颊尖距并且计算其差值绝对值X.②将双侧颏结节、双侧下颌角点在下颌牙合平面进行投影,两侧颏结节投影点连线为L1,左侧颏结节投影点与左侧下颌角点投影点连线L2,右侧颏结节投影点与右侧下颌角点投影点连线L3,L1与L2成角度为∠α,L1与L3成角为∠β,计算∠α与∠β差值绝对值Y.将数据导入SPSS13.0软件,分析X、Y两者之间的关系;将Y与偏突颌患者单颌矢状劈开截骨是否同期行水平向颏成形手术关联性,进行统计学分析.结果 X与Y存在线性正相关,直线回归方程为：Y= 1.15＋0.88X;Y〉（5.39±0.68）°时,偏突颌患者行SSRO术须同期行水平向颏成形手术.结论 偏突颌患者颏结节于下颌牙合平面投影点连线,分别与左右两侧颏结节投影点和下颌角点投影点连线所成夹角的差值绝对值〉（5.39±0.68）°时,行矢状劈开截骨术时须同期行水平向颏成形术.

Objective To reestablish of the three-dimensional skull model with the application of computer aided surgery simulation software to analyze the association between the genial asymmetry and horizontal genio- plasty and obtain the standard of the genioplasty in the horizontal. Methods Retrospectively study was per- formed on 40 patients with mandible laterognathism. Of them, 20 cases （Group A） was performed the horizontal genioplasty and sagittal split ramus osteotomy in single jaw simultaneously, the other 20 cases （Group B） was performed the sagittal split ramus osteotomy only. The preoperative dimensional spiral CT scan data were imported to the digital surgery software Surgicase 5.0 to reconstruct the three-dimensional skull model and establish the oc- clusal plane. （!） Measuring distance between the buccal groove of the mandibular first molar to the mesiobuccal cusp of maxillary first molar and calculate the absolute value of equation define X. （~ Projecting the bilateral mental tubers and the mandibular angles in the mandibular occlusal plane, were measured the angle value between the line linking bilateral chin tubers projected in the mandibular occlusal plane and the line linking projected points in the mandibular occlusal plane of chin tubers and mandibular angle point at the same side, and calculate the absolute value assign to Y. The measurement data were imported to SPSS13 0 software, analyze the relation- ship between the X and Y. The statistical analysis of the association between Y and if perform genioplasty in the horizontal following the SSRO at the same meanwhile was performed. Results 1. There was a positive linear cor- relation existing between X and Y and the linear regression equation was that： Y = 1.15 ＋ 0. 88X. 2. When Y was greater than 5.39 °±0.68°, there was a necessary to perform a horizontal genioplasty surgery following the sagittal split ramus osteotomy for the patients with mandible laterognathism. Conclusion The absolute equation value of angle between the line linking bilateral chin tubers projected in the mandibular occlusal plane and the line linking projected points in the mandibular occlusal plane of chin tubers and mandibular angle point at the same side is greater than 5.39 °±0.68°, it is a necessary to perform a horizontal genioplasty surgery following the sagittal split ramus osteotomy for the patients with mandible laterognathism.