目的 建立14岁青少年正常脊柱L3~L5节段三维有限元模型，分析不同程度腰椎间孔成形术后腰椎生物力学变化情况，为青少年椎间孔成形术改良提供参考。  方法 选择1名既往无腰椎病史的14岁女性志愿者，收集腰椎（L）CT影像数据导入Mimics 16.0软件建立模型，利用ABAQUS软件进行有限元模型受力分析。在正常脊柱L3~L5节段模型M的基础上建立M1（磨除L5左上关节突面积1/4）、M2（磨除L5左上关节突面积1/3）、M3（磨除L5左上关节突面积1/2）模型。在中立位及前屈、后伸等6种加载工况下测定相应节段关节突关节应力并进行比对分析。  结果 建立的三维有限元模型有效，方差分析模型有效。模型M1中，L5左上关节突在后伸、右旋转工况加载下应力值与模型M中应力值对比差异有统计学意义（P<0.05）；模型M2中，L4左上关节突在左侧屈、工况加载下应力值与模型M中应力值对比差异有统计学意义（P<0.05）；模型M3中，L4左上关节突在后伸工况，L5左上关节突在左侧屈、右侧屈、右旋转工况，L4右上关节突在右侧屈、右旋转工况，L5右上关节突在后伸、左侧屈、左旋转工况加载下应力值与模型M关节突应力值对比差异有统计学意义（P<0.05）。  结论 青少年椎间孔成形时，切除腰椎单侧单节段上关节突内侧面积 1/2 及以上时明显破坏腰椎生物力学稳定性，临床应慎重切除超过 1/2 以上的关节突关节面，以免导致腰椎不稳。

Objective To establish the three-dimensional finite element model of lumbar spine(L) 3-5 segments of the normal spine of 14-year-old adolescents to analyze the biomechanical changes of the lumbar spine after different degrees of lumbar foraminal plasty, and to provide reference for improvement of adolescent foraminoplasty.   Methods A14-year-old female volunteer with no previous history of lumbar spine was selected to collect lumbar CT image data and we imported it into Mimics 16.0 software for modeling. ABAQUS software was used to conduct finite element model force analysis. Models M1 (1/4 of the left superior facet area of L5 was removed), M2 (1/3 of the left superior facet area of L5 was removed) and M3 (1/2 of the left superior facet area of L5 was removed) were established on the basis of the normal vertebral column L3-L5 segment model M. The stress of facet joints of corresponding segments was measured and compared under six loading conditions, such as neutral position, forward flexion and extension.   Results The established three-dimensional finite element model and variance analysis model were effective. There was a statistically significant difference between the stress value of L5 in model M1 and that in model M under loading conditions of extension and right-rotation of the left superior articular process (P< 0.05). The stress value of L4 left superior articular process in model M2 under left flexion and loading condition was significantly different from that in model M (P<0.05). The model M3 L4 in the upper left articular process in the condition, L5 upper left articular process in a left turn, bow, bow on the right side, right the upper right of the L4 joints on the right side bends, right rotation condition, the upper right of the L5 joints in the stretch, left flexion, left rotating under the condition of loading stress value compared with model M articular process stress value difference was statistically significant (P<0.05).   Conclusion In adolescent foraminoplasty, the lumbar biomechanical stability is obviously damaged when the medial area of the superior facet of one side and one segment is excised. It is recommended to carefully remove the facet facet of more than 1/2 in clinical practice to avoid lumbar instability.