经口咽前路寰枢椎复位钢板固定的三维运动稳定性和抗拔出力研究

Biomechanical study on transoropharyngeal atlantoaxial reduction and fixation plate: three-dimension motional stability and anti-pull-out strength

目的 评价经口咽前路寰枢椎复位钢板 (TARP)的生物力学性能 ,包括三维运动范围和螺钉最大拔出力。方法 共 12例C0 ～C3 新鲜标本。 6例用于三维运动测试 ,分 7组 :(1)完整标本 (对照 ) ;(2 )损伤 (去除C1前弓、C2 齿突 ,破坏关节囊和横韧带等 ) ;(3)TARP ;(4 )后路Brooks钢丝 ;(5 )后路Magerl经关节螺钉 ;(6 )Magerl+Brooks;(7)前路经枢椎体寰椎侧块螺钉。分别测量其三维运动范围。另 6例(双侧n =12 )分解为单个椎体后用于螺钉拔出力测试 ,分 3组 :(1)寰椎 ;(2 )枢椎 ;(3)C3 (对照 ) ,分别测定最大拔出力。结果 TARP和Magerl+Brooks组在各个方向上的运动范围差异均无统计学意义 (P >0 0 5 ) ,二者抗屈伸、侧屈和旋转性能均强于其他 3种内固定方法 (P <0 0 5 )。C1、C2 、C3 的最大拔出力分别为 4 91 5 8±6 7 92、396 73± 6 0 99、385 5 3± 96 77N ,C1与C2 、C3 比较差异均有统计学意义(P <0 0 5 )。结论 TARP与目前临床应用最坚固的后路Magerl+Brooks固定等效 ,较其他 3种固定方法具有更坚强的固定作用 ;TARP具有良好的生物力学性能 。

Objective To evaluate the biomechanical stability of transoralpharyngeal atlantoaxial internal reduction plate(TARP),including range of motion(ROM) and anti-pull-out strength of screws. Methods Twelve fresh C 0～C 3 spine specimens were used for the study. Six specimens were used to compare the range of motion(ROM) after four kinds of anterio-posterior atlantoaxial arthrodesis, and divided into seven groups: (1)intact(control); (2)injured; (3)TARP fixation; (4)Brooks fixation; (5)Magerl fixation; (6)Magerl+Brooks fixation; (7)anterior transarticular screw fixation through C 2 vertebral body. The other six specimens(totally 12 cases including both sides) were designed to compare anti-pull-out strength of screws in C 1(atlas) and C 2(axis), and control C 3. Results No statistically significant difference was observed between the ROM of TARP and that of Magerl+Brooks (P>0.05). The ROM of flexion-extension, lateral bending and axial rotation of these two groups was smaller than that of the other three fixators(P<0.05).There was statistically significant difference between anti-pull-out strength screws in C 1 and C 2, and also C 3 (pull-out strength: C 1=491.58±67.92N, C 2=396.73±60.99N, C 3=385.53±96.77N)(P<0.05). No statistically significant difference was observed between anti-pull-out strength of screws in C 2 and C 3 (P>0.05). Conclusion Experimentally, the effect of TARP was equal to that of Magerl+Brooks, but it was proved to be more stable than the other three clinically widely used atlantoaxial fixators: Magerl, Brooks and anterior transarticular screw fixation through C 2 vertebral body. TARP's C 1 and C 2 screws were strong enough for atlanto-axial arthrodesis. TARP's biomechanical performance was excellent.