比格犬颈前路涂层螺钉的生物力学稳定性研究

目的 了解钛涂层、羟基磷灰石(hydroxyapatite,HA)涂层和钛+HA复合涂层螺钉置入体内后早期的生物力学稳定性。方法 选取成年比格犬32只平均分为4组:普通螺钉对照组(对照组)、HA涂层螺钉组(HA组)、钛涂层螺钉组(钛组)、钛+HA复合涂层螺钉组(复合组)。每组4只用该组相应螺钉固定于C_2~7作为无应力螺钉测试组(无应力组),共测试32枚螺钉,其中16枚螺钉作旋出扭矩测试,16枚螺钉作拔出力测试。记录旋出扭矩峰值、拔出力峰值和拔出能量。每组另4只作C₄/C₅椎间融合后采用该组螺钉+钛板固定于C_4,5椎体上作为应力螺钉测试组(应力组)。每组16枚螺钉作抗拔出力测试。记录螺钉的拔出力峰值和拔出能量。结果 在应力及非应力条件下,各组螺钉旋出扭矩峰值、拔出力峰值、断裂能量比较, HA组>复合组>钛组>对照组。结论 螺钉表面涂层能提高螺钉-骨组织界面的结合力。HA涂层螺钉的生物力学稳定性最好,钛涂层+HA复合涂层其次,提示HA的生物活性在置入早期可能对螺钉的生物力学稳定性起重要作用。

Biomechanical stability of coating screws in cervical vertebrae of beagle dogs

Objective To investigate the biomechanical stability of titanium coating screw, hydroxyapatite(HA) coating screw, and titanium+HA coating screw at 3 month after implantation in vivo study. Methods The 32 beagle dogs were divided into 4 groups: normal screws group(Control group), HA coating screw group(HA group), Titanium coating screw group (Titanium group), Titanium+HA coating screw group(Titanium+HA group).The designated screws were implanted in the cervical vertebra (C_2-7) of beagle dogs in every 4 dogs in each group as non-stress group. Extraction torque tests were carried out in 16 out of 32 screws. The pull-out resistance tests were carried out in the other 16 screws.The peak torque and the peak pull-out resistance were recorded. The other 4 dogs were designated as stress-group, anterior cervical fusion were performed at the C₄/C₅ level, screws were incerted with anterior plated at the C_4,5. The pull-out resistance tests were carried out in the these 16 screws. The peak pull-out resistance and energy were recorded. Results In both stress group and non-stress group, the peak torque, the peak pull-out resistance and energy were compared, HA group> Titanium+HA group>Titanium group>Control group. Conclusion The HA coating screw has the best biomechanical results at 3 months after implantation in vivo study.