Disch Alexander C, Schmoelz Werner
*Center for Musculoskeletal Surgery, Spine Unit, CHARITÉ University Hospital, Berlin, Germany; and †Department of Trauma Surgery, Laboratory for Biomechanics, Medical University Innsbruck, Austria.
Spine (Phila Pa 1976). 2014 Sep 1;39(19):E1147-53. doi: 10.1097/BRS.0000000000000470.
In vitro biomechanical investigation.
To assess differences in kyphosis after balloon kyphoplasty (BKP) or vertebral body stenting (VBS).
Cement augmentation techniques allow early mobilization in patients with osteoporotic thoracolumbar fractures. Biomechanically, the grade of reduction and preservation are as important as in nonosteoporotic fractures. With BKP, negative effects of balloon deflation on the reduction and whether specific combinations of materials may preserve the reduction are as yet unclear.
Twelve bisegmental human thoracolumbar specimens (6×T12-L2, 6×L3-L5; age at death, 76.3 yr; range, 63-89 yr; female:male ratio, 3:3; bone mineral density, 68.1 g/cm; mean, 12.9 g/cm) were tested in a spine simulator with pure moments of 7.5 Nm to assess primary and secondary stability. After flexibility testing of the intact specimens, an eccentric compression force induced standardized fractures, which were reduced using either BKP or VBS against a flexional moment of 2.5 Nm. Primary and secondary stability were assessed using range of motion in a spine tester. The specimens were tested after each of 3 periods of cyclic flexion loading. The kyphotic angle of the index vertebra was measured radiographically.
The 2 techniques achieved comparable reduction against a relatively high bending moment in this model. Neither technique restored the stability of the intact state; with increasing loads, the range of motion continuously increased to the level of fractured specimen to the level of the fractured specimen. Although the deflation effect on the kyphotic angle was lower with VBS (P≤0.05), there were no significant differences between the techniques relative to angle restoration.
Both augmentation techniques are able to restore vertebral body height after thoracolumbar fractures. The deflation effect on the kyphotic angle was less with VBS than with BKP. High flexion moments during implantation limit the effectiveness of reduction using cement augmentation methods.
N/A.
体外生物力学研究。
评估球囊后凸成形术（BKP）或椎体支架置入术（VBS）后脊柱后凸的差异。
骨水泥强化技术可使骨质疏松性胸腰椎骨折患者早期活动。在生物力学方面，复位程度和维持情况与非骨质疏松性骨折同样重要。对于BKP，球囊放气对复位的负面影响以及特定材料组合是否能维持复位尚不清楚。
选取12个双节段人体胸腰椎标本（6个为T12 - L2，6个为L3 - L5；死亡年龄76.3岁，范围63 - 89岁；男女比例3:3；骨密度68.1 g/cm，平均12.9 g/cm），在脊柱模拟器中施加7.5 Nm的纯力矩进行测试，以评估初次和二次稳定性。在对完整标本进行柔韧性测试后，施加偏心压缩力诱导标准化骨折，然后使用BKP或VBS对抗2.5 Nm的弯曲力矩进行复位。使用脊柱测试仪中的活动范围评估初次和二次稳定性。在3个周期的循环屈曲加载的每个阶段后对标本进行测试。通过X线测量指标椎体的后凸角度。
在该模型中，这两种技术在对抗相对较高的弯曲力矩时实现了相当的复位。两种技术均未恢复到完整状态的稳定性；随着负荷增加，活动范围持续增加至骨折标本的水平。尽管VBS对后凸角度的放气效应较低（P≤0.05），但在角度恢复方面，两种技术之间无显著差异。
两种强化技术均能够恢复胸腰椎骨折后的椎体高度。VBS对后凸角度的放气效应小于BKP。植入过程中的高弯曲力矩限制了使用骨水泥强化方法进行复位的效果。
无。
