Department of Orthopaedic and Trauma Surgery, Cologne University, Joseph-Stelzmann Street 9, 50924 Cologne, Germany.
Arch Orthop Trauma Surg. 2010 Feb;130(2):285-92. doi: 10.1007/s00402-009-1002-x.
When decompression of the lumbar spinal canal is performed, segmental stability might be affected. Exactly which anatomical structures can thereby be resected without interfering with stability, and when, respectively how, additional stabilization is essential, has not been adequately investigated so far. The present investigation describes kinetic changes in a surgically treated motion segment as well as in its adjacent segments.
Segmental biomechanical examination of nine human lumbar cadaver spines (L1 to L5) was performed without preload in a spine-testing apparatus by means of a precise, ultrasound-guided measuring system. Thus, samples consisting of four free motion segments were made available. Besides measurements in the native (untreated) spine specimen further measurements were done after progressive resection of dorsal elements like lig. flavum, hemilaminectomy, laminectomy and facetectomy. The segment was then stabilised by means of a rigid system (ART((R))) and by means of a dynamic, transpedicularly fixed system (Dynesys((R))).
For the analysis, range of motion (ROM) values and separately viewed data of the respective direction of motion were considered in equal measure. A very high reproducibility of the individual measurements could be verified. In the sagittal and frontal plane, flavectomy and hemilaminectomy did not achieve any relevant change in the ROM in both directions. This applies to the segment operated on as well as to the adjacent segments examined. Resection of the facet likewise does not lead to any distinct increase of mobility in the operated segment as far as flexion and right/left bending is concerned. In extension a striking increase in mobility of more than 1degree compared to the native value can be perceived in the operated segment. Stabilization with the rigid and dynamic system effect an almost equal reduction of flexion/extension and right/left bending. In the adjacent segments, a slightly higher mobility is to be noted for rigid stabilization than for dynamic stabilisation. A linear regression analysis shows that in flexion/extension monosegmental rigid stabilisation is compensated predominantly in the first cranial adjacent segment. In case of a dynamic stabilisation the compensation is distributed among the first and second cranial, and by 20% in the caudal adjacent segment.
Monosegmental decompression of the lumbar spinal canal does not essentially destabilise the motion segment during in vitro conditions. Regarding rigid or dynamic stabilisation, the ROM does not differ within the operated segment, but the distribution of the compensatory movement is different.
当对腰椎椎管进行减压时，节段稳定性可能会受到影响。究竟可以切除哪些解剖结构而不会干扰稳定性，以及分别在何时以及如何进行额外的稳定化，到目前为止还没有得到充分的研究。本研究描述了手术治疗的运动节段及其相邻节段的运动变化。
在脊柱测试装置中，通过精确的超声引导测量系统，对 9 个人体腰椎尸体标本（L1 至 L5）进行无预载的节段生物力学检查，从而获得由四个自由运动节段组成的样本。除了在原生（未经处理）脊柱标本中的测量外，还在逐步切除背侧结构（如黄韧带、半椎板切除术、椎板切除术和小关节切除术）后进行了进一步的测量。然后通过刚性系统（ART（R））和通过经皮固定的动态系统（Dynesys（R））对节段进行稳定化。
在分析中，等距测量了运动范围（ROM）值和分别观察到的各个运动方向的数据。可以验证各个测量的高度可重复性。在矢状面和额状面，黄韧带切除术和半椎板切除术在两个方向上均不会导致 ROM 的任何明显变化。这适用于手术节段和检查的相邻节段。小关节切除同样不会导致操作节段的活动度明显增加，就屈曲和左右弯曲而言。在伸展方面，与原生值相比，操作节段的活动度可增加 1 度以上。刚性和动态系统的稳定化作用几乎相等地降低了屈曲/伸展和左右弯曲。在相邻节段中，刚性稳定化的活动度略高于动态稳定化。线性回归分析表明，在屈伸时，单节段刚性稳定化主要在第一个颅侧相邻节段得到补偿。在动态稳定化的情况下，补偿分布在第一个和第二个颅侧，20%分布在尾侧相邻节段。
在体外条件下，腰椎椎管的单节段减压不会使运动节段基本不稳定。关于刚性或动态稳定化，ROM 在操作节段内没有差异，但补偿运动的分布不同。
