目的　分析双侧滑脱前期腰椎峡部裂患者腰椎静态和屈伸运动中动态矢状位旋转稳定性。方法   分析55例双侧滑脱前期腰椎峡部裂患者的腰椎X片，测量静态侧位片和过伸、过屈动力侧位片上发生峡部裂的L4/5或L5/S1节段的椎间盘角，并计算过伸和过屈侧位椎间盘角之差，和相应数量的正常体检者的对应指标随机对照，进行统计学分析。结果   双侧滑脱前期腰椎峡部裂患者和正常体检者腰椎静态侧位和过伸侧位片上对应节段的椎间盘角比较，差异无统计学意义（P>0.05）；过屈侧位椎间盘角及过伸过屈动力侧位椎间盘角之差，和正常体检者比较，差异有统计学意义（P＜0.05）。结论   双侧滑脱前期腰椎峡部裂在屈伸运动中存在着矢状位上的旋转不稳，需尽早进行外科干预。

Objective    To analyse the lumbar static and dynamic sagittal rotatable stability of patients with bilateral slipping prophase lumbar spondylolysis.   Methods    The lumbar X-ray of 55 patients with bilateral slipping prophase lumbar spondylolysis was analyzed. On the lateral X-ray radiography of  the lumbar spine under the conditions of  static and hyperflexion-hyperextension, the intervertebral disc angles of L4/5 or L5/S1 with spondylolysis were measured. The differences between the hyperflexion and hyperextension intervertebral disc angles were calculated. A randomized controlled study was performed between persons underwent physical check-ups and patients. the statistical analysis was performed.   Results    Intervertebral disc angles were not statistically different between patients with bilateral slipping prophase lumbar spondylolysis and persons underwent physical check-upson static and hyperextension lumbar lateral X-ray（P>0.05）. On lateral X-rayradiography under the condition of hyperflexion, the intervertebral disc angle was statistically different between them（P＜0.05）. The difference of intervertebral disc angle on lateral X-ray radiography under the conditions of hyperextension and hyperflexion was statistically significant（P＜0.05）. Conclusion   Dynamic sagittal rotatable instability exists on bilateral slipping prophase lumbar spondylolysis undergoing motion of flexion and extension. Surgical intervention needs to be provided as soon as possible