胸腰椎骨质疏松性骨折自固化磷酸钙骨水泥椎体成形的实验研究

目的探讨自固化磷酸钙骨水泥(calciumphosphatecement,CPC)注射椎体成形术后对胸腰椎骨质疏松性骨折椎体的力学影响。方法自愿捐赠的4具甲醛固定的老年尸体,取胸腰椎骨质疏松标本,平均年龄69岁,男、女各2具。每具标本随机取6个椎体,制备24个单椎体标本,建立前屈方向加载单椎体骨折模型。将CPC粉末与固化液以2.5g∶1ml调和制备CPC骨水泥,对骨折标本行CPC成形强化,每个椎体注射CPC约4ml。分别进行骨折前、成形后屈曲压缩力学检测。结果骨质疏松椎体标本骨折前最大载荷为1954±46N,位移长度为5.60±0.70mm,刚度为349±18N/mm;骨折间隙CPC填塞成形后最大载荷为2285±34N,位移为5.35±0.60mm,刚度为427±10N/mm,各指标骨折前和成形后比较差异均有统计学意义(P<0.05)。CPC加强成形后单椎体的承载能力强度较骨折前提高16.92%,刚度较骨折前提高22.31%。结论椎体内注射CPC能明显恢复骨质疏松骨折椎体的力学性能。

BIOMECHANICAL INFLUENCE OF VERTEBROPLASTY WITH FILLING WITH AUTOSOLIDIFICATION CALCIUM PHOSPHATE CEMENT IN THORACOLUMBAR OSTEOPOROTIC FRACTURES

OBJECTIVE: To investigate the biomechanical influence of vertebroplasty using autosolidification calcium phosphate cement (CPC) on thoracolumbar osteoporotic fractures. METHODS: Four cadaver specimens with osteoporosis were applied to make spine unit. There were 2 females and 2 males, whose average age was 69 years. All underwent flexion-axial loading to result in vertebral body fracture. Following reduction, the middle fractured vertebral body were strengthened by the method of vertebroplasty, using CPC. Before fracture and after vertebroplasty, all were conducted biomechanical test. RESULTS: After being packed CPC to the space in the fractured vertebral body, the strength and stiffness in vertebroplastic group (2 285+/-34 N, 427+/- 10 N/mm) were significantly higher than that in osteoporotic group (1 954+/-46 N, 349+/-18 N/mm) (P<0.05). The vertebral height changing in vertebroplastic group (5.35+/-0.60 mm) were significantly lower than that in osteoporotic group (5.60+/-0.70 mm) (P<0.05). And the fractured body increases its strength and stiffness by 16.92% and 22.31% respectively in comparison with its initial situation. CONCLUSION: After being injected CPC into bone trabecular interspaces, the fractured vertebral bodies can restore its strength and stiffness markedly.