Wu Yungang, Wang Yinhai, Wu Jinhui, Guan Junjie, Mao Ningfang, Lu Chunwen, Lv Runxiao, Ding Muchen, Shi Zhicai, Cai Bin
Department of Orthopedics, Changhai Hospital Affiliated to Second Military Medical University, China.
Department of Orthopedics, The First People's Hospital of Changxing County, China.
World Neurosurg. 2016 Feb;86:294-9. doi: 10.1016/j.wneu.2015.09.038. Epub 2015 Sep 25.
Degeneration of intervertebral disks in the lower lumbar spine is associated with significant structural alterations. Finite element model has been widely used in the study of spinal mechanical behaviors. Our study used this technique to characterize the motional influence to the double-level (L4-5 and L5-S) degeneration.
Three grades of disk degeneration were modeled with the changes in geometry and material properties. In the extension and flexion of range of motion (ROM), single segment degeneration in L4-5 or L5-S resulted in a decreased angle in itself and increased angle in the other segment. Double-level degeneration resulted in a decreased rotation in both segments. Bending resulted in a decreased ROM in all 3 grades of degeneration in the double-level degeneration. In torsion loading, mild and moderate single degeneration in L4-5 and L5-S increased the rotation angle. In double-level degeneration, mild and moderate L4-5 degeneration increased the L4-5 rotation angle by 14%-19%. In contrast, severe L4-5 decreased L4-5 rotation angle. Concurrently, mild and moderate L5-S degeneration increased the rotation angle, respectively, by 15% and 6%, and severe degeneration decreased the rotation angle by 29%.
Different loading motions in double-level degeneration had differing effects on the ROM. These changes are important to understand the biomechanics of the progression of disk degeneration in the lower lumbar spine. Our results provide insights for the clinical intervention of double-level intervertebral disks.
下腰椎椎间盘退变与显著的结构改变相关。有限元模型已广泛应用于脊柱力学行为的研究。我们的研究使用该技术来描述双节段（L4 - 5和L5 - S）退变的运动影响。
模拟了三个等级的椎间盘退变，包括几何形状和材料特性的变化。在屈伸活动度（ROM）方面，L4 - 5或L5 - S单节段退变导致自身角度减小，另一节段角度增加。双节段退变导致两个节段的旋转均减小。侧弯导致双节段退变的所有三个等级的ROM均减小。在扭转加载时，L4 - 5和L5 - S的轻度和中度单节段退变增加了旋转角度。在双节段退变中，L4 - 5的轻度和中度退变使L4 - 5旋转角度增加了14% - 19%。相比之下，L4 - 5的重度退变减小了L4 - 5旋转角度。同时，L5 - S的轻度和中度退变分别使旋转角度增加了15%和6%，重度退变使旋转角度减小了29%。
双节段退变中不同的加载运动对ROM有不同影响。这些变化对于理解下腰椎椎间盘退变进展的生物力学很重要。我们的结果为双节段椎间盘的临床干预提供了见解。
