Objective Coflex interspinous stabilization is a kind of device for the treatment of degenerative disc disease.The key of this surgery is the distance between the spinal dura mater and the Ushaped bottom of Coflex.The influence of different insertion depth of Coflex on the transition segment is the focus of our research.This paper aims to evaluate the influence of the distance between the U-shaped bottom of Coflex and the spinal dura mater on the postoperative lumbar stability via in vitro experiment.Methods Six lumbar spine specimens (L1/L5) from fresh adult cadavers were used in this experiment.Each specimen was divided into 6 groups according to the experimental process:intact state group(A),unstable state group (B),10 mm insertion state group (C),5 mm insertion state group (D),0 mm insertion state group (E) and fusion group (F).The movement tests of lumbar specimen were performed under conditions of flexion and extension,lateral bending,and axial rotation.The movement angle and range of motion (ROM) were employed to analyze the stability of thc transition segment.Results With regard to the angle range of transition segment for all testing groups,the order of similarity between group A and other groups was:E＞D＞C＞B＞F.The ROM of group E was smaller than that of other groups,and group E was of larger stiffness.Conclusions This indicates that the performance of transition segment after surgery is closer to the normal spine when the insertion position of Coflex is near the spine during the flexion and extension,lateral bending,and axial rotation.%目的 腰椎棘突间动态稳定装置Coflex是一种临床上腰椎退行性疾病手术治疗的器械,在置入时其U形底部与硬脊膜之间的距离是手术的关键,Coflex置入不同深度后对手术节段的影响是本文关注的问题.本文通过体外实验评估Coflex的U形底部与硬脊膜的距离对术后腰椎稳定性的影响.方法 选取成年新鲜尸体腰椎(L1-L5)标本6具.每个标本按照实验过程分为6组模型:完整组(A组)、失稳组(B组)、10 mm安装组(C组)、5 mm安装组(D组)、0 mm安装组(E组)、融合组(F组).对模型进行前屈/后伸、左右侧弯、左右旋转6个方向的运动测试,通过观察手术节段的运动角度和关节活动度(range of motion,ROM)来分析其稳定性.结果 各实验组手术节段运动角度与完整组的相似性为E组＞D组＞C组＞B组＞F组;ROM的计算结果显示,E组的ROM值比其他组相对较小,刚度较大.结论 前屈后伸、左右侧弯、左右旋转6种方向运动时,棘突间动态稳定装置Coflex置入位置距脊柱较近时,术后手术节段性能更加接近正常腰椎.
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