Panjabi Manohar, Henderson Gweneth, Abjornson Celeste, Yue James
Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
Spine (Phila Pa 1976). 2007 May 20;32(12):1311-9. doi: 10.1097/BRS.0b013e318059af6f.
An in vitro human cadaveric biomechanical study.
To evaluate intervertebral rotation changes due to lumbar ProDisc-L compared with simulated fusion, using follower load and multidirectional testing.
Artificial discs, as opposed to the fusions, are thought to decrease the long-term accelerated degeneration at adjacent levels. A biomechanical assessment can be helpful, as the long-term clinical evaluation is impractical.
Six fresh human cadaveric lumbar specimens (T12-S1) underwent multidirectional testing in flexion-extension, bilateral lateral bending, and bilateral torsion using the Hybrid test method. First, intact specimen total range of rotation (T12-S1) was determined. Second, using pure moments again, this range of rotation was achieved in each of the 5 constructs: A) ProDisc-L at L5-S1; B) fusion at L5-S1; C) ProDisc-L at L4-L5 and fusion at L5-S1; D) ProDisc-L at L4-L5 and L5-S1; and E) 2-level fusion at L4-L5 to L5-S1. Significant changes in the intervertebral rotations due to each construct were determined at the operated and nonoperated levels using repeated measures single factor ANOVA and Bonferroni statistical tests (P < 0.05). Adjacent-level effects (ALEs) were defined as the percentage changes in intervertebral rotations at the nonoperated levels due to the constructs.
One- and 2-level ProDisc-L constructs showed only small ALE in any of the 3 rotations. In contrast, 1- and 2-level fusions showed increased ALE in all 3 directions (average, 7.8% and 35.3%, respectively, for 1 and 2 levels). In the disc plus fusion combination (construct C), the ALEs were similar to the 1-level fusion alone.
In general, ProDisc-L preserved physiologic motions at all spinal levels, while the fusion simulations resulted in significant ALE.
一项体外人体尸体生物力学研究。
通过跟随负荷和多方向测试，评估与模拟融合相比，腰椎ProDisc-L导致的椎间旋转变化。
与融合术不同，人工椎间盘被认为可减少相邻节段的长期加速退变。由于长期临床评估不切实际，生物力学评估可能会有所帮助。
使用混合测试方法，对6个新鲜人体尸体腰椎标本（T12-S1）进行屈伸、双侧侧弯和双侧扭转的多方向测试。首先，确定完整标本的总旋转范围（T12-S1）。其次，再次使用纯力矩，在以下5种结构中分别实现该旋转范围：A）L5-S1节段植入ProDisc-L；B）L5-S1节段融合；C）L4-L5节段植入ProDisc-L且L5-S1节段融合；D）L4-L5和L5-S1节段均植入ProDisc-L；E）L4-L5至L5-S1节段进行双节段融合。使用重复测量单因素方差分析和Bonferroni统计检验（P < 0.05），确定每个结构在手术节段和非手术节段导致的椎间旋转的显著变化。相邻节段效应（ALE）定义为由于这些结构导致的非手术节段椎间旋转的百分比变化。
单节段和双节段ProDisc-L结构在任何一种旋转中仅显示出较小的ALE。相比之下，单节段和双节段融合在所有三个方向上均显示ALE增加（单节段和双节段的平均值分别为7.8%和35.3%）。在椎间盘加融合组合（结构C）中，ALE与单节段融合相似。
总体而言，ProDisc-L在所有脊柱节段均保留了生理运动，而融合模拟导致了显著的ALE。
