Department of Orthopedics, University of California, Irvine, CA.
Orthopaedic Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach and Department of Orthopaedic Surgery, University of California, Irvine, CA.
Spine (Phila Pa 1976). 2019 Apr 1;44(7):E393-E399. doi: 10.1097/BRS.0000000000002868.
A biomechanical in vitro study using human cadaveric spines.
The aim of this study was to compare atlantoaxial stability and stiffness of a C1 lateral mass - C2 short pedicle - C3 lateral mass screw-rod construct versus C1 lateral mass - C2 pedicle screw-rod construct.
The C1 lateral mass - C2 pedicle screw-rod construct provides excellent atlantoaxial fixation, but C2 pedicle screw placement is associated with risk of vertebral artery injury. The use of shorter C2 pedicle screws may mitigate the risk of vascular injury but may result in reduced C1-C2 stabilization. Extending C1 lateral mass - C2 short pedicle screw-rod construct with C3 lateral mass screws may mitigate the risk of vascular injury without compromising C1-C2 fixation.
Seven cervical spines were tested with internal control experimental design in the following sequence: intact state, and following creation of type II odontoid fracture, the specimen was instrumented with C1 lateral mass - C2 pedicle screw fixation (C2PED), C1 lateral mass - C2 short pedicle screw fixation (C2SPED), and C1 lateral mass - C2 short pedicle - C3 lateral mass screw fixation (C2SPED-C3LM). For each condition, the angular stiffness and range of motion (ROM) with 1.5-Nm load in flexion/extension (FE), lateral bending (LB), and right/left axial rotation (RAR/LAR) were quantified.
Instrumented conditions demonstrated significantly lower C1-C2 angular ROM and greater stiffness than the intact state. Compared with C2PED, C2SPED-C3LM demonstrated significantly lower C1-C2 ROM during FE and LB, significantly greater C1-C2 stiffness in flexion and right/left LB, similar C1-C2 ROM and stiffness in RAR/LAR, and similar stiffness in extension. C2SPED-C3LM demonstrated significantly greater atlantoaxial stabilization in the sagittal and coronal planes than C2PED construct.
Compared with C2PED, C2SPED-C3LM may be a suitable alternative surgical strategy for atlantoaxial instability that provides superior atlantoaxial fixation.
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一项使用人体尸体脊柱的生物力学体外研究。
本研究的目的是比较 C1 侧块 - C2 短椎弓根 - C3 侧块螺钉棒结构与 C1 侧块 - C2 椎弓根螺钉棒结构的寰枢椎稳定性和刚度。
C1 侧块 - C2 椎弓根螺钉棒结构提供了极好的寰枢椎固定，但 C2 椎弓根螺钉的放置与椎动脉损伤的风险有关。使用较短的 C2 椎弓根螺钉可能会降低血管损伤的风险，但可能会导致 C1-C2 稳定性降低。用 C3 侧块螺钉扩展 C1 侧块 - C2 短椎弓根螺钉棒结构可能会降低血管损伤的风险，而不会影响 C1-C2 固定。
使用内部对照实验设计，按以下顺序对 7 个颈椎进行测试：完整状态，以及 II 型齿状突骨折形成后，标本用 C1 侧块 - C2 椎弓根螺钉固定（C2PED）、C1 侧块 - C2 短椎弓根螺钉固定（C2SPED）和 C1 侧块 - C2 短椎弓根 - C3 侧块螺钉固定（C2SPED-C3LM）。对于每种情况，在 1.5-Nm 载荷下的屈伸（FE）、侧屈（LB）和右/左轴向旋转（RAR/LAR）的角度刚度和运动范围（ROM）进行量化。
仪器固定状态下的 C1-C2 角度 ROM 和刚度明显低于完整状态。与 C2PED 相比，C2SPED-C3LM 在 FE 和 LB 时 C1-C2 ROM 明显较低，屈伸和右/左 LB 时 C1-C2 刚度明显较大，RAR/LAR 时 C1-C2 ROM 和刚度相似，而在伸展时刚度相似。与 C2PED 结构相比，C2SPED-C3LM 在矢状面和冠状面具有更好的寰枢椎稳定性。
与 C2PED 相比，C2SPED-C3LM 可能是一种治疗寰枢椎不稳定的合适替代手术策略，可提供更好的寰枢椎固定。
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Zotero 插件