부산대학교 도서관

背景:后路寰-枢椎椎弓根钉棒内固定是治疗寰枢椎脱位的主要方法,横连接在内固定系统抗旋转能力中起着重要作用.新型寰椎钉尾横连可以有效克服传统横连安装不便、影响植骨床和脊髓损伤可能等缺点,但不同安装模式的新型钉尾横连的生物力学性能尚不清楚. 目的:测试不同安装模式的新型寰椎钉尾横连在后路寰-枢椎椎弓根钉棒内固定系统中的生物力学特性,为临床选择最佳安装模式提供理论依据. 方法:6具新鲜人体枕颈标本作为完整组(A组),在完整组基础上建立Ⅱ型齿状突骨折的寰枢椎失稳模型(B组),在失稳组基础上对每具标本先后进行后路寰-枢椎椎弓根钉、棒内固定(C组),在C组上依次安装不同模式新型寰椎钉尾横连,其中包括上水平横连(两寰椎螺钉钉尾)为D组,下水平横连(两枢椎螺钉钉尾)为E组,斜形横连(左上右下为F组,左下右上为G组),交叉横连为H组.在三维运动机上将标本模型按顺序进行前屈、后伸、左右侧屈和左右旋转测试,获取各个内固定状态下的寰枢椎活动度.运用重复测量方差分析评价各组模型的生物力学特性. 结果与结论:①在6种工况下,A、C、D、E、F、G、H组寰枢椎活动度小于B组,差异均有显著性意义(P＜0.05);②在前屈、后伸状态下,5种横连内固定组相比无统计学差异(P＞0.05);③在左右旋转方向上,D、E组与F、G、H组对比差异均有显著性意义(P＜0.05),D与E组,F与G组组间对比无统计学差异(P＞0.05),F、G与H组对比亦无统计学差异(P＞0.05);④提示在前屈、后伸状态下,5种钉尾横连组生物力学稳定性相当;但在左右旋转状态下,斜形钉尾横连和交叉钉尾横连的稳定性明显优于上下钉尾横连组;而斜形钉尾横连具备和交叉横连同等的抗旋转稳定性,故值得临床优先推荐.
BACKGROUND:Posterior atlantoaxial pedicle screw rod internal fixation is the main method for treating atlantoaxial dislocation,and the horizontal crosslink plays an important role in the antirotation ability of the internal fixation system.The new horizontal screw-screw crosslink can effectively overcome the disadvantages of traditional horizontal crosslink,such as inconvenient installation,impact on bone grafting bed,and potential spinal cord injury.However,the biomechanical properties of the new horizontal screw-screw crosslink with different installation modes are still unclear. OBJECTIVE:To investigate the biomechanical characteristics of new different installation modes of horizontal screw-screw crosslink in the C1-C2 pedicle screw-rod fixation and to provide a theoretical basis for optimal installation mode. METHODS:Six fresh human occipitocervical specimens were divided into the intact state group(group A),and the atlantoaxial instability model of type Ⅱ odontoid fracture was established based on the intact state group as the instability group(group B).The C1-C2 pedicle screw-rod fixation was performed on each specimen based on the instability group(group C).In group C,different installation modes of horizontal screw-screw crosslink were successively installed in each specimen,including upper transverse connection(two atlas screw tails)as group D,lower transverse connection(two axis screw tails)as group E,diagonal transverse connection(upper left and lower right for group F,lower left and upper right for group G),and cross transverse connection as group H.The specimen models were tested in order of flexion,extension,lateral flexion and lateral rotation on a three-dimensional motion machine,and the atlantoaxial range of motion of each group of specimens was obtained.Repeated measure analysis of variance was used to evaluate the biomechanical properties of each group. RESULTS AND CONCLUSION:(1)Under six states,the range of motion of groups A,C,D,E,F,G and H was smaller than that of group B,and there were statistically significant differences(P＜0.05).(2)In the flexion and extension states,there was no significant difference among the five types of horizontal screw-screw crosslink groups(P＞0.05).(3)In the left and right rotation directions,there were significant differences in D and E groups compared with F,G and H groups(P＜0.05);there were no significant differences between D and E groups,and F and G groups(P＞0.05),and there were no significant differences in F and G groups compared with H group(P＞0.05).(4)In conclusion,under flexion-extension states,the biomechanical stability of five types of horizontal screw-screw crosslink groups was similar,but under the rotation state,the stability of diagonal horizontal screw-screw crosslink group and cross horizontal screw-screw crosslink group was obviously better than that of transverse horizontal screw-screw crosslink group;however,the stability of diagonal horizontal screw-screw crosslink group is similar to the cross horizontal screw-screw crosslink group,so the former is more worthy of clinical recommendation.