Department of Neurosurgery, University of South Florida, Tampa, FL, USA.
Spine (Phila Pa 1976). 2010 Apr 20;35(9):931-8. doi: 10.1097/BRS.0b013e3181c16f9a.
A human cadaveric biomechanical study comparing craniocervical fixation techniques.
To quantitatively compare the biomechanical stability of a new technique for occipitocervical fixation using the occipital condyles with an established method for craniocervical spine fusion.
Stabilization of the occipitocervical junction remains a challenge. The occiput does not easily accommodate instrumentation because of access and spatial constraints. In fact, the area available for the implant fixation is limited and can be restricted further when a suboccipital craniectomy has been performed, posing a challenge to current fixation techniques. Occipital screws are also associated with the potential for intracranial complications.
Six fresh frozen cadaveric specimens occiput-C4 were tested intact, after destabilization and after fixation as follows: (1) occipital plate with C1 lateral mass screws and C2 pars screws and (2) occipital condyle screws with C1 lateral mass screws and C2 pars screws. Specimens were loaded in a custom spine testing apparatus and subjected to the following tests, all performed under 50-N unconstrained axial preload: flexion, extension, lateral bending, and axial rotation at 1.5 Nm. The constructs were statistically compared with a one-way analysis of variance and compared with the intact condition.
Motions were reduced by approximately 80% compared with the intact condition for both configurations under all motions. There were no statistically significant differences in the range of motion (ROM) between the 2 instrumentation conditions. The mean values indicated decreased ROM with the novel occipital condyle screw construct in comparison with the standard occipital plate and rod system.
Craniocervical stabilization using occipital condyle screws as the sole cephalad fixation point is biomechanically equivalent with regard to the modes tested (ROM and stiffness) to the standard occipital plate construct.
比较颅颈固定技术的人体尸体生物力学研究。
定量比较使用枕骨髁进行枕颈固定的新技术与颅颈脊柱融合的既定方法的生物力学稳定性。
枕颈交界部的稳定仍然是一个挑战。由于进入和空间限制，枕骨不容易适应器械。实际上，可用于植入物固定的区域是有限的，当进行枕下颅骨切除术时，可进一步限制，这对当前的固定技术构成了挑战。枕骨螺钉也存在潜在的颅内并发症。
共测试了 6 具完整的新鲜冷冻尸体枕骨-C4 标本，分别为完整、失稳后和固定后：（1）带有 C1 侧块螺钉和 C2 弓根螺钉的枕骨板，和（2）带有 C1 侧块螺钉和 C2 弓根螺钉的枕骨髁螺钉。标本在定制的脊柱测试仪器中加载，并进行以下测试，所有测试均在 50-N 无约束轴向预载下进行：屈曲、伸展、侧屈和轴向旋转 1.5 Nm。使用单向方差分析对这些结构进行统计学比较，并与完整状态进行比较。
与完整状态相比，两种器械配置在所有运动下的运动幅度均减少了约 80%。两种器械条件下的运动范围（ROM）无统计学差异。与标准枕骨板和棒系统相比，新型枕骨髁螺钉结构的平均 ROM 减小。
使用枕骨髁螺钉作为唯一的颅侧固定点进行颅颈固定在测试模式（ROM 和刚度）方面与标准枕骨板结构具有生物力学等效性。
