Fuller Amy M, Chui Jennifer M, Cook Daniel J, Yeager Matthew S, Gladowski David A, Cheng Boyle C
Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, PA.
Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, PA ; Department of Neurosurgery, Drexel University College of Medicine, Pittsburgh, PA.
Int J Spine Surg. 2012 Dec 1;6:1-7. doi: 10.1016/j.ijsp.2011.12.001. eCollection 2012.
Pure moment testing is a common method used in cadaveric spine testing. The fundamental basis for the widespread acceptance of applying a pure moment is uniform loading along the column of the spine. To our knowledge, this protocol has not been experimentally verified on a multi-degree of freedom testing apparatus. Given its ubiquitous use in spine biomechanics laboratories, confirmation of this comparative cadaveric test protocol is paramount.
Group A specimens (n =13) were used to test the pure moment protocol, by use of 3 constructs that changed the number of involved vertebrae, orientation, and rigidity of the spine construct. Group B specimens (n = 6) were used to determine whether potting orientation, testing order, or degradation affected the range of motion (ROM) by use of 8 constructs. Each group was subjected to 3 cycles of flexion-extension, lateral bending, and axial torsion. The data from the third cycle were used to calculate the ROM for each method.
Group A testing resulted in significant differences in ROM across the 3 constructs for lateral bending and axial torsion (P < .02) and trended toward a difference for flexion-extension (P = .055). Group B testing showed an increase in ROM across 8 constructs (P < .04) but no significant difference due to the orientation change.
The increased ROM across constructs observed in both groups indicates that the cause is likely the testing order or degradation of the specimens, with orientation having no observed effect. The data do not invalidate pure moment testing, and its use should persist.
纯力矩测试是尸体脊柱测试中常用的方法。纯力矩应用被广泛接受的基本依据是沿脊柱柱体的均匀加载。据我们所知，该方案尚未在多自由度测试设备上进行实验验证。鉴于其在脊柱生物力学实验室中的普遍使用，确认这种比较性尸体测试方案至关重要。
A组标本（n = 13）用于测试纯力矩方案，使用了3种改变脊柱结构中受累椎体数量、方向和刚度的结构。B组标本（n = 6）用于通过使用8种结构来确定灌封方向、测试顺序或降解是否会影响运动范围（ROM）。每组均进行3个周期的屈伸、侧弯和轴向扭转。来自第三个周期的数据用于计算每种方法的ROM。
A组测试结果显示，在3种结构中，侧弯和轴向扭转的ROM存在显著差异（P < .02），屈伸的ROM有差异趋势（P = .055）。B组测试显示，8种结构的ROM均增加（P < .04），但因方向改变无显著差异。
两组中观察到的各结构ROM增加表明，原因可能是测试顺序或标本降解，方向未观察到有影响。这些数据并未使纯力矩测试无效，其应用应继续。
