经单侧椎弓根灌注固化磷酸钙骨水泥和聚甲基丙烯酸甲酯椎体成形的实验效果比较

Comparison of effects of unipedicular vertebroplasty between injection of autosetting calcium phosphate cement and injection of polymethylmethacrylate

目的比较经单侧椎弓根灌注自固化磷酸钙骨水泥(autosetting calcium phosphate cement,ACPC)和聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)椎体成形的效果。方法用离体连续三节胸腰椎标本共10个,分别测定中间椎体和相邻椎间盘非破坏性载荷下标本运动时的应力、应变和刚度值。造成中间椎体压缩骨折的同时测定其极限载荷和刚度值。然后标本随机分成2组,分别经单侧椎弓根灌注3mL ACPC和PMMA椎体成形后再同前测试。结果椎体成形术后,两组中间椎体扭转刚度较初始皆有下降,两组之间有显著性差异;两组中间椎体抗压极限载荷较初始都有显著性提高;ACPC组椎体极限刚度不能恢复;PMMA组相邻椎间盘应力显著增加21%左右。结论经单侧椎弓根灌注ACPC和PMMA都能较好恢复椎体的生物力学性能,但在扭转刚度和极限刚度的恢复上灌注PMMA稍好一些。灌注ACPC椎体成形后相邻椎间盘不出现高应力现象和载荷传递异常效应,有望降低相邻椎体继发骨折的发生率。

Purpose To compare effects of unipedicular vertebroplasty between injection of autosetring calcium phosphate cement（ACPC） and injection of polymethylmethacrylate（PMMA）. Methods Ten specimens consisting of continuous three thoracolumbar vertebae were obtained. Initial stress, strain and axial stiffness of middle vertebrae and adjacent intervertebral discs were determined during motion of specimens under nondestructive load. When flexional compression fractures were experimentally created in the middle vertebrae, their utmost strength and stiffness were measured. Then specimens were divided into two groups randomly. The middle vertebral bodies were then stabilized by unipedicular injection of 3mL ACPC or PMMA respectively. All the specimens were tested ibid. Results After vertebroplasty, torsion stiffness in both groups declined obviously compared with the initial and there was significant difference between them. Utmost strength significantly increased in both groups compared with the initial. Utmost stiffness in ACPC group couldn＇t restore. In PMMA group stress of adjacent intervertebral disc increased by 21%. Conclusions Unipedicular vertebroplasty injection of both cements can restore vertebral mechanical property of vertebra, but vertebroplasty injection of PMMA has a little superiority in respect of restoration of torsion stiffness and utmost stiffness. High stress and abnormity in load shift of adjacent intervertebral disc after vertebroplsty injection of ACPC didn＇t happen, which brought promise of lower rate of new fractures of adjacent vertebrae.