Wittenberg R H, Shea M, Hayes W C
Department of Orthopedic Surgery, Charles A. Dana Research Institute, Harvard-Thorndike Laboratory, Beth Israel Hospital, Boston, Massachusetts, USA.
Spine (Phila Pa 1976). 1995 Jun 1;20(11):1227-32. doi: 10.1097/00007632-199506000-00003.
In human lumbosacral spines, the flexibility and intersegmental distraction allowed by four monosegmental and bisegmental intrapedicular devices during compression and flexion/compression loading were investigated.
To compare the flexibility and intersegmental distraction allowed by four monosegmental and bisegmental intrapedicular, lumbosacral fixation devices applied to destabilized cadaveric spines, and to determine the effect of each device on the flexibility and intersegmental distraction of the motion segment above each fused segment.
The lumbosacral segment is the most mobile region in the lumbar spine, exhibiting the highest range of motion in both flexion and extension. Therefore, the fixation of this and the adjacent segment is of special clinical interest.
L5-S1 facetectomy or L5 laminectomy procedures were performed on cadaveric human lumbosacral spines. Fixation devices then were applied across one or two levels, and intersegmental motion under flexion/compression or under pure compression loads was monitored.
The flexibility and posterior strain allowed by the four implants did not differ significantly between implants. The strain across the stabilized site (monosegmental and bisegmental) was below 10% for all devices tested. The flexibility and distraction were reduced to levels below intact after the fixators were applied. The distraction across the segment above the fusion was not increased because of fixation with these four fixators.
Angular stable fixation devices, such as those described here, provide adequate stabilization of the posteriorly destabilized spine.
在人体腰骶椎中，研究了四种单节段和双节段椎弓根内固定装置在压缩及屈曲/压缩载荷下所允许的灵活性和节段间撑开情况。
比较应用于不稳定尸体脊柱的四种单节段和双节段腰骶椎弓根内固定装置所允许的灵活性和节段间撑开情况，并确定每种装置对每个融合节段上方运动节段的灵活性和节段间撑开的影响。
腰骶段是腰椎中活动度最大的区域，在屈曲和伸展时均表现出最大的活动范围。因此，该节段及相邻节段的固定具有特殊的临床意义。
对尸体腰骶椎进行L5 - S1小关节切除术或L5椎板切除术。然后在一个或两个节段应用固定装置，并监测屈曲/压缩或纯压缩载荷下的节段间运动。
四种植入物所允许的灵活性和后伸应变在植入物之间无显著差异。所有测试装置在稳定部位（单节段和双节段）的应变均低于10%。应用固定器后，灵活性和撑开程度降低至低于完整状态的水平。由于使用这四种固定器进行固定，融合节段上方节段的撑开并未增加。
如本文所述的角度稳定固定装置可为后部不稳定的脊柱提供充分的稳定作用。
