新型颈椎前路经椎弓根固定钉板系统的研制及生物力学分析

Development and biomechanical analysis of a new anterior cervical pedicle screw fixation system

背景:临床中为了解决颈椎翻修/骨质疏松/长节段固定等问题,一般选择进行前、后路联合内固定来获得满意的术后稳定性,难免加重患者的手术创伤,增加术后并发症概率及住院费用。而颈前路反向椎弓根内固定可通过一次前路手术获得前后路联合内固定的稳定性,但临床缺少适用的颈前路椎弓根内固定系统。目的:依据颈椎相关解剖结构研制出新型颈椎前路经椎弓根固定钉板系统,并在新鲜尸体颈椎标本上评价其生物力学性能,为初步临床应用提供依据。方法:通过颈椎标本解剖数据获得新型钉板系统三维数值,通过3D打印技术制作出该系统。采用新鲜成人尸体颈椎标本,在完整状态下测量生物力学稳定性(A组:完整组);再制成C5-7失稳模型,依次在传统颈椎前路钉板系统固定(B组)、新型颈椎前路经椎弓根固定钉板系统4枚螺钉固定(C组)、新型颈椎前路经椎弓根固定钉板系统6枚螺钉固定(D组)的不同固定状态下进行位移、轴向刚度、扭转刚度等生物力学测试。结果与结论:①在载荷-位移关系方面:D组平均位移较C组小25%,D组较B组小30%,C组较B组小18%,差异均有显著性意义(P<0.05);②在颈椎的轴向刚度方面:D组比C组高20%,比B组高40%;C组比B组固定时高20%,D和C组均优于A组,差异均有显著性意义(P<0.05);③在颈椎的扭转刚度方面:D组高于C组21%,高于B组40%;C组高于B组30%,差异均有显著性意义(P<0.05);④生物力学测试显示,在载荷-位移、轴向刚度及扭转刚度方面,新型颈椎前路经椎弓根锁定导向内固定系统组优于传统组,同时6钉固定组(D组)优于4钉固定组(C组);提示新型颈前路经椎弓根固定钉板系统符合国人解剖特征且具有优于传统固定方式的力学稳定性,为临床提供了一种可靠的新型颈椎前路经椎弓根内固定系统。

BACKGROUND:In clinical practice,to solve the problems of cervical spine revision/osteoporosis/long-segment fixation,anterior and posterior internal fixation is generally chosen to obtain satisfactory postoperative stability,which will inevitably aggravate the surgical trauma of the patients and increase probability of postoperative complications and hospitalization costs.The anterior cervical reverse pedicle internal fixation can obtain the stability of the anterior and posterior combined internal fixation through a single anterior operation,but there is no clinically applicable anterior cervical pedicle fixation system.OBJECTIVE:A new anterior cervical pedicle screw fixation system was developed based on the relevant anatomical structure of the cervical spine,and its biomechanical properties were evaluated on fresh cadaver cervical spine specimens to provide a basis for preliminary clinical application.METHODS:The three-dimensional numerical value of the new nail plate system was obtained from the anatomical data of cervical spine specimens,and the system was produced by three-dimensional printing technology.Fresh adult cadaver cervical spine specimens were used to measure biomechanical stability in intact state(group A:complete group),and then to make a C5-7 instability model,followed by traditional cervical anterior nail plate system fixation(group B),anterior cervical spine displacement,strength,stiffness,torsion torque,under the fixed state of four screws fixed by the pedicle screw system(group C)and six screws(group D)of the anterior cervical pedicle screw system(group D)test.RESULTS AND CONCLUSION:(1)In terms of load-displacement relationship:the average displacement difference between group D and group C after the test was 25%,group D and group B were 30%,and group C and B were 18%,and the differences were statistically significant(P<0.05).(2)In terms of the axial stiffness of the cervical spine:group D was 20% higher than group C and 40% higher than group B;group C was 20% higher than group B when fixed;group D and C were both better than group A;the differences were statistically significant(P<0.05).(3)In terms of torsion mechanical properties of the cervical spine:the group D was higher than group C by 21%,higher than group B by 40%;group C was higher than group B by 30%;the difference was statistically significant(P<0.05).(4)Biomechanical tests showed that in terms of load-displacement,axial stiffness and torsional mechanical properties,the anterior cervical pedicle locking and guiding internal fixation system group was better than the traditional group.The six-screw fixation group(group D)was better than the four-screw fixation group(group C).It is concluded that the new anterior cervical pedicle screw fixation system conforms to Chinese anatomy and has better mechanical stability than traditional fixation methods.It is a new reliable anterior cervical pedicle internal fixation system for clinical practice.