纳米羟基磷灰石/涂层双相磷酸钙人工骨移植脊柱后外侧融合:组合磁场的辅助作用

Nano-hydroxyapatite coated biphasic calcium phosphate for posterolateral lumbar fusion: combined magnetic field plays an auxiliary role

背景:自体骨移植是脊柱融合的主要方法,但其来源有限,而且伴有很多并发症的发生,人工合成材料已成为最有前途的骨移植替代材料。目的:观察组合磁场和纳米羟基磷灰石涂层对双相磷酸钙人工骨移植兔脊柱后外侧融合的影响。方法:制作48只兔双侧L5/6横突间融合模型,随机分成6组:G1组为组合磁场+自体髂骨;G2组为组合磁场+纳米羟基磷灰石/双相磷酸钙;G3组为组合磁场+双相磷酸钙;G4组为安慰剂+自体髂骨;G5组为安慰剂+纳米羟基磷灰石/双相磷酸钙;G6组为安慰剂+双相磷酸钙。术后1周开始组合磁场治疗,30 min/d,治疗8周后处死实验动物,分别进行触摸法、X射线、CT、组织学(脱钙和不脱钙骨)和生物力学评估脊柱融合效果。结果与结论:(1)触摸法、X射线法和组织学评估G2组脊柱融合率最高,G6组最低,差异有显著性意义(P<0.05)。G2组新生骨长入比显著高于G3,G5组和G6组(P<0.05);(2)X射线片显示融合区校正吸光度指数G2组显著高于其他各组(P<0.05);(3)CT和组织学可见新生骨小梁从自体骨长入人工骨孔隙内,与自体骨形成骨性结合;(4)生物力学结果显示,G2组脊柱弯曲刚度最高,显著高于其他各组(P<0.05);(5)析因分析结果显示,组合磁场治疗和纳米羟基磷灰石涂层可显著提高脊柱融合率、融合评分、骨长入比、融合区校正吸光度指数及脊柱融合弯曲刚度(P<0.05);(6)结果提示,组合磁场联合纳米羟基磷灰石/双相磷酸钙生物支架进行兔脊柱后外侧融合能够显著提高融合率,融合效果类似于单纯的自体骨融合,可作为脊柱融合的一种新方式。

BACKGROUND：Autologous bone is considered the main material for spinal fusion, while synthetic materials overcome the shortcomings caused by the autologous bone（complications and limited source） and become the most promising bone graft substitute materials. OBJECTIVE：To investigate the effects of nano-hydroxyapatite （nano-HA） coating and combined magnetic field （CMF） on the biphasic calcium phosphate （BCP） transplantation for rabbit posterolaterallumbar fusion. METHODS：Forty-eight rabbits underwent bilateral intertransverse processes fusion at the level of L5-6, and were then randomly divided into six groups： rabbits in group G1 received autologous iliac bone graft and CMF treatment; group G2wasgiven nano-HA/BCP and CMF treatment; group G3 received BCP and CMF treatment; group G4 received autologous iliac bone graft and placebo; group G5 underwent nano-HA/BCP and placebo; group G6 received BCP and placebo. CMF treatment was performed30 minutes each dayfor8 consecutive weeksbeginning at 1 week after surgery. These rabbits were euthanized at 9 weeks after surgery toevaluatespinal fusion effects throughpalpation, X-ray examination, CTexamination, histological analysis （decalcified and undecalcified sections） and biomechanical assessment. RESULTS AND CONCLUSION：The palpation, X-rayand histologicalexaminationsshowed that there was significant difference in the fusion rate between groupsG2 and G6, the highest in the group G2, and the lowest in the groupG6 （P〈 0.05）.The bone ingrowth rate in the group G2 was significantly higher than those in the groups G3, G4 and G6 （P〈0.05）. The normalized optical density index of fusion mass and bending stiffness in the group G2 were significantly higher than those in the other groups （P〈 0.05）. CT and histological observations found that new bone trabecula grew into the biological scaffold, exhibiting osseointegration. Factorial analysis showed that CMF and nano-HA coating could significantly improve the spinal fusion rate, fusion score, bone ingrowth rate and bending stiffness （P〈 0.05）. In conclusion, CMF combined with nano-HA/BCP for rabbitposterolaterallumbar fusion can significantlyamelioratethe fusion rate, which is analogous to the single autologous bone;therefore, it can be used as a new spinal fusion method.