羟基磷灰石喷涂型椎间植入物与皮质骨界面的结合特性

Ingrowth characteristics of the interface between hydroxyapatite coated intervertebral implant and vertebral cortex

目的观察在生理负荷下羟基磷灰石表面喷涂型椎间植入物的界面介导皮质骨长入形成骨性结合的特性。方法建立直立动物椎间植入物-椎体皮质骨界面研究动物模型,制作猕猴型椎间植入物12个,金刚砂磨面(对照组)4个、羟基磷灰石表面喷涂(观察组)8个。取4只成年猕猴,分别在其L2,3、L3,4和L4,5椎间隙随机放置2个羟基磷灰石喷涂及1个金刚砂磨面植入物。于术后3、6、12、24、40周行X线摄片,40周非脱钙骨切片行骨界面形态计量学分析及组织学观察。结果术后第3天全部动物恢复站立,行走,步态正常。观察期间植入物无松动及移位。术后40周观察组骨界面主要以部分矿化的类骨质及钙化良好的成熟骨组织充填,单位视野成骨细胞和骨细胞数明显增多(t=16.983,P=0.000),矿化骨组织百分含量高于对照组(t=5.001,P=0.000)。羟基磷灰石涂层无碎裂及剥脱,与骨组织界面密合。结论羟基磷灰石与椎体皮质骨具有良好的组织相容性,在体内性质稳定,在椎间压应力生理负荷下,较金刚砂磨面能更好地介导椎体皮质骨组织长入骨界面,形成骨性结合。

Objective To observe the ingrowth characteristics of the interface between hydroxyapatite coated intervertebral implants and vertebral cortex loaded with physiological compressive stress. Methotis Twelve titanium alloy intervertebral implants special for macaque were prepared, 4 of which were coated with corundum （control group） and 8 of which were coated with hydroxyapatite （HA, observed group）. One control and two observed implants were randomly inserted into the intervertebral spaces of L2,3, L3,4 and L4,5 in each of 4 healthy homogenous adult macaques （2 males and 2 females）. Roentgenology was performed at 3, 6, 12, 24 and 40 weeks postoperatively. Histomorphometry as well as histology were also evaluated at 40 weeks postoperatively. Results All the animals recovered well from the operation. Three days after operation all the animals began to stand and walk with normal gait. Gross anatomy showed excellent healing in the annulus fibrous involved, and no implant loosening or migration was found. On 40 weeks postoperatively, the interface of the observed group were filled with calcified mature bone and partly-mineralized osteoid tissue, the content of calcified bone as well as the amount of osteoblasts and osteocytes were significantly higher in observed group, and the differences were of statistical significance （t=5.001, P=0.000 and t=16.983, P= 0.000）. A tight connection was observed between the vertebral bones and HA coating. The thickness of coating decreased form 130-150 μm to 100-130 μm. And no evident breakage or debris was found on the implant coating. Condusion HA coating was stable in vivo and had favorable biocompatibility with vertebral bone. It was more effective than corundum coating in inducing intervertebral cortical bone ingrowth under physical compressive loading.