金属橡胶角度人工颈椎间盘植入后颈椎的稳定性变化

Cervical stability changes following metal rubber cervical disc replacement

背景:前期实验设计和制作了钛合金金属橡胶角度人工颈椎间盘假体,于试图复制椎间盘在运动及应力分布这两方面的作用上进行了可行性研究。目的:进一步观察金属橡胶角度人工颈椎间盘植入后山羊颈椎的稳定性变化。方法:将9只山羊随机分为手术组(n=6)和正常对照组(n=3),手术组在C4/5节段植入金属橡胶角度人工颈椎间盘,正常对照组不予任何处理。分别于术前,术后即刻、4周、8周、12周行X射线正侧位、过伸过屈位,测量C4/5节段椎间隙高度、活动度及椎间角度,并进行手术节段硬组织切片包埋,苦味酸品红骨染色和扫描电镜观察。结果与结论:手术组术后不同时间点C4/5节段椎间隙高度、脊柱活动度与术前及正常对照组比较差异无显著性意义;手术组术后即刻、4周、8周C4/5节段椎间角度高于术前(P<0.05);手术组术后4,8,12周C4/5节段椎间角度与正常对照组比较差异无显著意义(P>0.05)。术后4周时,手术组骨尚未与假体边缘接触;8周时骨与假体边缘间隙缩小,假体边缘有少量新生骨附着;12周时,假体表面有少量骨细胞存在,假体内部已有新生骨组织长入。表明金属橡胶角度人工椎间盘植入椎间隙后短期可维持椎间隙高度和活动度,与椎体结合牢固。

BACKGROUND： Previous studies designed and made titanium metal rubber cervical disc prosthesis, and performed feasible studies on its effect on movement and stress distribution by replicating intervertebral discs. OBJECTIVE： To further observe the changes in the stability of goat cervical vertebra after metal rubber cervical disc replacement. METHODS： Nine goats were randomly divided into experimental group （n=6） and normal control group （n=3）. Goats in the experimental group received metal rubber cervical disc replacement at C4/5 segment. Goats in the normal control group did not receive any treatment. Radiographic data at anteroposterior and lateral position, hyperextension and excessive flexion were taken to measure intervertebral height, range of motion and intervertebral angle at C4/5 segment before operation, immediately, 4, 8, 12 weeks after operation. Subsequently slicing and embedding of hard tissue at surgical segment, picric acid-acid fuchsin staining and scanning electron microscopy were conducted.RESULTS AND CONCLUSION： No significant difference in the intervertebral height and spinal range of motion at C4/5 segment at different time points was detected between postoperative results in the experimental group and preoperative results in the experimental group, normal control group. The intervertebral height at C4/5 segment was higher immediately 4 and 8 weeks after surgery than preoperative result in the experimental group （P 〈 0.05）. No significant difference in intervertebral angle at C4/5 segment was detectable between 4, 8 and 12 weeks postoperatively in the experimental group and normal control group （P 〈 0.05）. At 4 weeks after surgery, bone did not contact with the edge of the prosthesis in the experimental group. At 8 weeks, the gap between bone and the prosthesis became small, and some new bone attached to the edge of the prosthesis. At 12 weeks, a few osteoblasts were observed on the surface of the prosthesis. New osteogenic tissue grew into the prosthesis. Results suggested that metal rubber cervical disc replacement in the intervertebral space could maintain intervertebral height and range of motion in a short period, and tightly bind to the vertebral body.