Two-Level Noncontiguous Versus Three-Level Anterior Cervical Discectomy and Fusion A Biomechanical Comparison
Two-Level Noncontiguous Versus Three-Level Anterior Cervical Discectomy and Fusion A Biomechanical Comparison
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DOI：
10.1097/brs.0b013e3181fd5d7c
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发表时间：
2011-03-15
期刊：
影响因子：
3
通讯作者：
Brodke, Darrel S.
中科院分区：
文献类型：
--
作者：
Finn, Michael A.;Samuelson, Mical M.;Brodke, Darrel S.
研究设计.生物力学研究。确定两个或三个节段融合治疗非相邻节段后施加在中间节段和相邻节段上的生物力学力。邻近融合脊柱节段的运动增加被认为是邻近节段退变的驱动力。有时，患者需要治疗正常节段两侧的非相邻节段。施加在中间和邻近水平的生物力学力是未知的。将七个完整的人尸体颈椎（C3-T1）安装在定制的七轴脊柱模拟器中，该模拟器配备有随动载荷装置和OptoTRAK三维跟踪系统。在+/- 1.5 Nm力矩和100 Nm轴向随动载荷下，每个完整样本均接受了5次屈曲/伸展、侧弯和轴向旋转循环。记录每个运动轴和节段的施加扭矩和运动数据。在C4-C5和C6-C7椎间盘切除并使用刚性颈椎钢板和椎间融合器融合后，以及在C4-C7三个节段融合后，在相同参数下重复测试。跳跃式融合结构的中间和相邻节段的活动度适度增加（35%）。在九个时刻中的七个时刻达到了显著或接近显著的差异。对于三节段融合结构，与完整和两节段非连续结构相比，在所有施加的力矩中，相邻节段下和相邻节段上的活动度显著或接近显著增加。这种变化的幅度是实质性的（72%）。在三节段融合的所有时刻，相邻节段和相邻节段上方的应变显著增加，而两节段融合的中间、相邻节段上方和相邻节段下方的应变相对于完整节段而言是适度的。当遇到非相邻疾病时，考虑非相邻融合而不是三节段融合是合适的。
Study Design. Biomechanical study.Objective. To determine biomechanical forces exerted on intermediate and adjacent segments after two-or three-level fusion for treatment of noncontiguous levels.Summary of Background Data. Increased motion adjacent to fused spinal segments is postulated to be a driving force in adjacent segment degeneration. Occasionally, a patient requires treatment of noncontiguous levels on either side of a normal level. The biomechanical forces exerted on the intermediate and adjacent levels are unknown.Methods. Seven intact human cadaveric cervical spines (C3-T1) were mounted in a custom seven-axis spine simulator equipped with a follower load apparatus and OptoTRAK three-dimensional tracking system. Each intact specimen underwent five cycles each of flexion/extension, lateral bending, and axial rotation under a +/- 1.5 Nm moment and a 100-Nm axial follower load. Applied torque and motion data in each axis of motion and level were recorded. Testing was repeated under the same parameters after C4-C5 and C6-C7 diskectomies were performed and fused with rigid cervical plates and interbody spacers and again after a three-level fusion from C4 to C7.Results. Range of motion was modestly increased (35%) in the intermediate and adjacent levels in the skip fusion construct. A significant or nearly significant difference was reached in seven of nine moments. With the three-level fusion construct, motion at the infra-and supra-adjacent levels was significantly or nearly significantly increased in all applied moments over the intact and the two-level noncontiguous construct. The magnitude of this change was substantial (72%).Conclusion. Infra-and supra-adjacent levels experienced a marked increase in strain in all moments with a three-level fusion, whereas the intermediate, supra-, and infra-adjacent segments of a two-level fusion experienced modest strain moments relative to intact. It would be appropriate to consider noncontiguous fusions instead of a three-level fusion when confronted with nonadjacent disease.