Tai Ching-Lung, Hsieh Pang-Hsing, Chen Weng-Pin, Chen Lih-Huei, Chen Wen-Jer, Lai Po-Liang
Graduate Institute of Medical Mechatronics, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan.
BMC Musculoskelet Disord. 2008 Jun 11;9:84. doi: 10.1186/1471-2474-9-84.
The association of lumbar spine instability between laminectomy and laminotomy has been clinically studied, but the corresponding in vitro biomechanical studies have not been reported. We investigated the hypothesis that the integrity of the posterior complex (spinous process-interspinous ligament-spinous process) plays an important role on the postoperative spinal stability in decompressive surgery.
Eight porcine lumbar spine specimens were studied. Each specimen was tested intact and after two decompression procedures. All posterior components were preserved in Group A (Intact). In Group B (Bilateral laminotomy), the inferior margin of L4 lamina and superior margin of L5 lamina were removed, but the L4-L5 supraspinous ligament was preserved. Fenestrations were made on both sides. In Group C (Laminectomy) the lamina and spinous processes of lower L4 and upper L5 were removed. Ligamentum flavum and supraspinous ligament of L4-L5 were removed. A hydraulic testing machine was used to generate an increasing moment up to 8400 N-mm in flexion and extension. Intervertebral displacement at decompressive level L4-L5 was measured by extensometer
The results indicated that, under extension motion, intervertebral displacement between the specimen in intact form and at two different decompression levels did not significantly differ (P > 0.05). However, under flexion motion, intervertebral displacement of the laminectomy specimens at decompression level L4-L5 was statistically greater than in intact or bilateral laminotomy specimens (P = 0.0000963 and P = 0.000418, respectively). No difference was found between intact and bilateral laminotomy groups. (P > 0.05).
We concluded that a lumbar spine with posterior complex integrity is less likely to develop segment instability than a lumbar spine with a destroyed anchoring point for supraspinous ligament.
椎板切除术和椎板切开术之间腰椎不稳的关联已进行了临床研究，但相应的体外生物力学研究尚未见报道。我们研究了以下假设：后复合体（棘突-棘间韧带-棘突）的完整性在减压手术的术后脊柱稳定性中起重要作用。
对8个猪腰椎标本进行研究。每个标本在完整状态下以及经过两种减压手术后进行测试。A组（完整组）保留所有后部结构。B组（双侧椎板切开术组）切除L4椎板下缘和L5椎板上缘，但保留L4-L5棘上韧带。两侧开窗。C组（椎板切除术组）切除下L4和上L5的椎板和棘突。切除L4-L5的黄韧带和棘上韧带。使用液压试验机在屈伸过程中产生逐渐增加至8400 N-mm的力矩。通过引伸计测量减压水平L4-L5处的椎间位移。
结果表明，在伸展运动下，完整状态的标本与两个不同减压水平的标本之间的椎间位移无显著差异（P>0.05）。然而，在屈曲运动下，减压水平L4-L5的椎板切除术标本的椎间位移在统计学上大于完整或双侧椎板切开术标本（分别为P = 0.0000963和P = 0.000418）。完整组和双侧椎板切开术组之间未发现差异（P>0.05）。
我们得出结论，与棘上韧带锚固点被破坏的腰椎相比，后复合体完整的腰椎发生节段性不稳的可能性较小。
