不同寰軸椎後方固定技術之有限元素法評估

在交通意外事故發生高速撞擊下，汽車的安全氣囊及機車騎士所戴的安全帽，非常容易造成頸椎的損傷。根據美國高速公路管理局的資料顯示，損傷部位發生在枕骨（occipital）到頸椎第二節（C2）的部位佔整個頸椎損傷的78%。對於治療第一頸椎及第二頸椎（寰軸椎）損傷或不穩定，在以往的文獻已有許多種不同固定寰軸椎（C1、C2）的方式，但大部分還是採用後方手術固定的方式。為了瞭解目前臨床上較常使用寰軸椎後方固定手術之固定效果，本研究以有限元素法來比較下列四種不同寰軸椎後方手術的固定方式：（1）Halifax金屬鉤固定、（2）關節間骨螺絲固定、（3）側塊骨螺絲與骨板固定、（4）椎弓骨螺絲與骨板固定，模擬寰軸椎在不同的受力（前彎、後仰、側彎、旋轉）情況下之固定效果。根據分析的位移結果顯示，以側塊骨螺絲與骨板、椎弓骨螺絲與骨板的固定較佳，關節間骨螺絲的固定次之，Halifax金屬鉤的固定最差。以內固定器蒙麥氏應力分佈情況，以椎弓骨螺絲與骨板較佳，Halifax金屬鉤最差。從本研究中所得之結果，與臨床上手術情況的考量，使用椎弓骨螺絲與骨板是比較建議的寰軸椎手術固定的方式。

關鍵字

骨融合；固定器；頸椎；寰軸椎；有限元素法

並列摘要

Under the circumstances of the traffic accidents occured at a high speed collision, the usage of safety helmets and airbags for motorcyclist and automobile passengers are likely to cause damage in the cervical spine. According to the survey from the United States National Highway Traffic Safety Administration (NHTSA), upper cervical spinal injury (occipital to C2) accounts for approximately 78 % of all cervical injuries. For the treatments of atlantoaxial instability, various surgical fixation techniques had been advocated. Most surgeons prefer posterior approaches. The stabilities of four most commonly-used C1-2 fixation devices were compared in this study. They are: (1) Halifax clamp (2) transarticular screw fixation (3) lateral mass screw-plate system (4) pedicle screw-plate system. Finite element analyses were performed for four different loading conditions in daily activities, including flexion, extension, lateral bending and axial rotation. According to the results from comparing the displacement between C1 and C2, the lateral mass screw-plate and pedicle screw-plate were the most rigid fixation and the Halifax clamp was the least rigid fixation. The stability of transarticular screws fixation was better than Halifax clamp and closer to the stability of the other two plate fixations. For comparison of the maximal von Mises stress for the four fixation devices, the pedicle screw-plate had the lowest stress and the Halifax clamp had the highest stress among the four fixation devices. From the biomechanical and clinical viewpoint, we concluded that for the treatment of C1-2 instability, the pedicle screw-plate fixation is the recommended fixation type to be used in atlantoaxial fusion surgery.

並列關鍵字

Cervical spine ； Bone fusion ； Atlantoaxial spine ； Finite element analysis ； Fixation device

參考文獻

【1】 Nightingale RW, Winkelstein BA, Knaub KE, Richardson WJ, Luck JF, Myers BS: Comparative strengths and structural properties of the upper and lower cervical spine in ﬂexion and extension. J Biomechanics 35:725-732,2003

【2】 Stokes JK, Villavucencio AT, Liu PC, Bray RS, Johnson JP: Posterior atlantoaxial stabilization: new alternative to C1–2 transarticular screws. J Neurosurg(Spine 2) 12:1-5, 2002

【3】 Dull ST, Toselli RM: Preoperative oblique axial computed tomographic imaging for C1-2 transarticular screw fixation: technique note. Neurosurgery 37:150-152, 1995

【4】 Eleraky MA, Masferrer R, Sonntag VKH : Posterior Atlantoaxial facet screw fixation in rheumatoid arthritis. J Neurosurg 89:8-12,1998

【5】 Grob D, Jeanneret B, Aebi M, Markerwalder T-M. Atlantoaxial fusion with transarticular screw fixation. J Bone Joint Surg(Br) 73:972-976,1991

國際替代計量

不同寰軸椎後方固定技術之有限元素法評估

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