人工髓核防滑脱装置的设计及生物力学评价

Design and biomechanics of artificial nucleus wrapping with fascia lata

背景:人工髓核置换治疗腰椎间盘病变能减轻或消除腰腿痛的临床症状、维持椎间盘高度、保留脊柱节段的稳定性和活动度,但因假体移位而再手术率较高。目的:设计人工髓核防滑脱装置(用阔筋膜包裹人工髓核)并进行生物力学评价。设计:自身对照,生物力学体外实验。材料:成年人新鲜尸体腰椎(L1～S1)标本3具;尸体大腿阔筋膜标本2片;人工髓核为自制,材料为聚甲基丙烯酸甲酯。方法:将3具腰椎标本制成6个运动节段的试验模型,L3～4及L4～5各3个,制成椎间盘髓核摘除后单纯人工髓核置入模型,施加前屈后伸、左右侧弯和左右轴向旋转6个方向6.0N·m的纯力偶矩疲劳实验。然后取出人工髓核,用备用的阔筋膜包裹缝合,制成椎间盘髓核摘除后用阔筋膜包裹人工髓核置入模型,进行相同的生物力学测试。主要观察指标:不同状态各个方向髓核假体移位的变化。结果:与单纯人工髓核置入相比较,阔筋膜包裹人工髓核置入在脊柱屈伸与旋转时髓核在水平方向上移位减小(P<005),在脊柱侧屈时髓核在水平方向上移位减小(P<001);而在脊柱屈伸、旋转或侧屈时人工髓核在冠状面和额状面上的成角移位均减小(P<001)。结论:阔筋膜包裹人工髓核置入在体外人体标本测试中能较好地减小或防止人工髓核假体移位。

BACKGROUND： Artificial nucleus replacement can alleviate or eliminate symptoms of back leg pain, maintain intervertebral height, and retain stability and activity range of spinal segments in treating intervertebral disc disorder. However, the re-surgery rate is high due to prosthesis displacement. OBJECTIVE： To design artificial nucleus wrapping with fascia lata and to evaluate its biomechanical properties. DESIGN： Self-control and biomechanical experiment. MATERIALS： Three fresh adult cadaveric specimens （lumber vertebrae of L1-S1）; two samples of thigh fascia lata from cadaver; self-made artificial nucleus by polymethyl methacrylate. METHODS： The lumber vertebrae of L1-S1 were used to establish 6 trial models （3 models each of L3-4 and L4-5）. Following nucleotomy, artificial nucleus alone replacement was performed and the models were exposed to moment of couple test of 6.0 N · m at forward flexion, backward extension, left and right lateral bending and left and right axial rotation. The artificial nucleus was removed, and replaced with nucleus wrapping with fascia lata, followed by the same biomechanical tests. MAIN OUTCOME MEASURES： Prosthesis displacement at different directions. RESULTS： The displacement of nucleus in nucleus wrapping group was much less than nucleus alone group at flexion/extension and rotation （P 〈 0.05）, and at horizontal levels （P 〈 0.01）. In addition, nucleus wrapping group showed a significant reduction in angle-formation with both the frontal and coronal planes at flexion, extension, lateral bending or rotation （P 〈 0.01）. CONCLUSION： Artificial nucleus wrapping with fascia lata is an effective method in reducing or preventing nucleus from displacement after artificial nucleus replacement.