Slosar P J, Patwardhan A G, Lorenz M, Havey R, Sartori M
Department of Orthopaedic Surgery, Loyola University Medical Center, Maywood, Illinois, USA.
Spine (Phila Pa 1976). 1995 Jul 1;20(13):1452-61. doi: 10.1097/00007632-199507000-00003.
This study analyzed the changes in the load-displacement behavior of lumbar spine segments caused by burst fractures that were experimentally produced in fresh human cadaveric spines. The effect of three transpedicular surgical constructs on stability was investigated in each specimen.
To quantify the loss of mechanical stiffness caused by the injury, and to evaluate the stiffness of three transpedicular surgical constructs.
Although various investigators have studied the biomechanical characteristics of the burst fracture and surgical stabilization techniques, few have reported quantitative data on the three-dimensional biomechanical instability of these fractures.
Load-displacement data were acquired in flexion, lateral bending, and axial rotation for intact specimens, after the L1 burst fracture was created and after the T12-L2 segments were stabilized using Luque plates, VSP plates, and Isola rods with one transverse connector.
Spines with burst fractures showed a bilinear load-displacement behavior with significant instability (loss of stiffness relative to intact) at low loads (up to 3 N.m) in flexion, lateral bending, and axial rotation. The loss of stiffness was greatest in axial rotation over the entire load range (up to 10 N.m). If posterior element injury also was present, a significantly larger loss of stiffness was observed in flexion and axial rotation. The three transpedicular constructs improved the stability of the injured spine beyond that of the intact spine in flexion and lateral bending at low loads. At high loads, they restored the stiffness to intact levels. However, in axial rotation they did not restore the stiffness to pre-injury level, particularly when the posterior column was disrupted.
Reduction of the burst fracture returns the spine to its position of greatest inherent instability, essentially requiring the transpedicular instrumentation to be load bearing. To enhance mechanical stability, it may be necessary to augment the transpedicular construct, particularly when the posterior column is disrupted.
本研究分析了新鲜人尸体腰椎因爆裂骨折导致的节段性载荷-位移行为变化。在每个标本中研究了三种经椎弓根手术固定结构对稳定性的影响。
量化损伤导致的机械刚度损失，并评估三种经椎弓根手术固定结构的刚度。
尽管众多研究者已对爆裂骨折的生物力学特性及手术稳定技术进行了研究，但很少有人报告这些骨折三维生物力学不稳定性的定量数据。
在完整标本、制造L1爆裂骨折后以及使用Luque钢板、VSP钢板和带有一个横向连接器的Isola棒对T12-L2节段进行固定后，分别采集其在屈曲、侧弯和轴向旋转时的载荷-位移数据。
患有爆裂骨折的脊柱在屈曲、侧弯和轴向旋转时呈现双线性载荷-位移行为，在低载荷（高达3 N·m）时具有明显的不稳定性（相对于完整脊柱刚度损失）。在整个载荷范围（高达10 N·m）内，轴向旋转时的刚度损失最大。如果同时存在后部结构损伤，则在屈曲和轴向旋转时观察到刚度损失明显更大。三种经椎弓根固定结构在低载荷下的屈曲和侧弯时，改善了损伤脊柱的稳定性，使其超过完整脊柱。在高载荷下，它们将刚度恢复到完整水平。然而，在轴向旋转时，它们并未将刚度恢复到损伤前水平，尤其是当后柱受损时。
爆裂骨折复位使脊柱回到其固有不稳定性最大的位置，本质上需要经椎弓根器械承受载荷。为增强机械稳定性，可能有必要加强经椎弓根固定结构，尤其是当后柱受损时。
