经伤椎与跨伤椎万向钉置钉固定脊柱骨折的生物力学对比研究

Multiaxial inter-vertebral and vertebral pedicle pedicle screw fixation for spinal fractures： a biomechanical comparative study

目的 对比评估经伤椎6钉与跨伤椎4钉固定脊柱骨折的生物力学稳定性.方法 6具新鲜冰冻小牛腰椎标本L1～L5节段,制备成腰椎前中柱损伤模型.比较4钉固定组与6钉固定组的三维6个方向的运动范围.结果 生物力学试验证实,4钉固定组在屈曲、后伸运动方向上的稳定性都较对照组小,但差异无统计学意义.6钉固定组在屈曲、后伸运动方向上的稳定性均较完整对照组大,且差异有统计学意义（t=4.844,P＜0.01;t=3.722,P＜0.05）.6钉固定组在各个方向的运动范围均小于4钉固定组,且两组在屈曲、后伸、侧屈、旋转运动方向差异均有统计学意义（P＜0.05,0.01）.结论 6钉固定较4钉固定在屈曲、后伸、侧屈、旋转各运动上的生物力学强度强,为临床应用微创经皮万向钉6钉固定治疗胸腰椎骨折提供了理论依据.

Objective To compare the biomechanical stability of the multiaxial inter-vertebral and vertebral pedicle screw fixation in vertebral fracture fixation of the spinal fracture model. Methods Six lumbar fracture models were made on fresh calf lumbar spine specimens at L1 -L5 to compare the stability of four transpedicular multiaxial screws and six transpedicular multiaxial screws by examining the range of motion （ROM） in flexion, extension, lateral bending and torsion. Results Biomechanical experiment found that four multiaxial screws transpedicular fixation specimen exhibited a significantly larger ROM in flexion and extension than the intact specimens; while six multiaxial transpedicular screw fixation specimen exhibited a smaller ROM than the intact specimens （t =4. 844,P 〈0. 01 ;t =3. 722,P 〈0.05 ）. The ROM of six multiaxial transpedicular screw fixation specimen was significantly smaller than that of four multiaxial transpedicular screw fixation specimen in flexion, extension, lateral bending and rotation （ P 〈 0. 01 ）. Conclusions Compared with four multiaxial transpedicular screw fixation, six multiaxial transpedicular screw fixation exhibits a significantly larger stability in flexion, extension, lateral bending and rotation, as provides theoretical basis for treatment of thoracolumbar fractures with pedicular screw fixation.