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[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.