山羊可动人工腰椎复合体研制及在体生物力学研究

目的：研制适用于山羊腰椎次全切除术后重建的可动人工腰椎复合体（mobile artificial lumbar complex,MALC），测试MALC的稳定性及术后腰椎节段运动功能。方法：选取18只1～2岁雄性波尔山羊（体重35～45 kg），将其分为对照组、融合组、非融合组，每组6只。根据术前腰椎X线片、CT及MRI检查，针对非融合组设计个体化山羊MALC，并进行3D打印制作。分别对3组进行手术，对照组仅显露椎体及椎间盘；融合组切除L4部分椎体及上下完整椎间盘组织，进行钛网植骨腰椎接骨板固定手术；非融合组同法切除椎体及椎间盘，植入MALC。术后6个月拍摄山羊腰椎正侧位X线片了解内植物有无脱位、移位及断裂，并在力学测试仪上对标本进行生物力学试验，测量L2,3、L3,4、L4,5椎间隙的运动范围（range of motion,ROM）和L2-5整体腰椎ROM。结果：设计MALC进行3D打印，制造其组件人工椎体及上下人工终板，半球体结构采用高交联聚乙烯材料应用精密车床加工而成，并完成假体组装。术后6个月腰椎正侧位X线片示腰椎融合内植物及MALC植入位置良好，未见移位脱位。腰椎标本体外生...

Development and in vivo biomechanics of goat mobile artificial lumbar spine complex

Objective Mobile artificial lumbar complex (MALC) which suitable for reconstruction after subtotal lumbar resection in goats was developed,and to test stability of the complex and postoperative lumbar segmental motor function. Methods Eighteen male boer goats aged from 1 to 2 years old (weighted from 35 to 45 kg) were selected and divided into control group,fusion group and non-fusion group,with 6 goats in each group. According to preoperative CT scans and MRI examinations of lumbar,the goat MALC was designed and performed by 3D printed for non-fusion group. Operation was performed on three groups respectively,and only vertebral body and disc were exposed in control group. In fusion group,L₄ part of vertebral body and the upper and lower complete disc tissues were removed,and the lumbar spine bone plate fixation was performed with titanium mesh bone grafting. In non-fusion group,vertebral body and disc were removed in the same way,and MALC was implanted. AP and lateral X-rays of lumbar vertebrae in goat were taken at 6 months after surgery,in order to understand whether the plant was dislocated,displaced and fractured. Biomechanical tests were performed on the specimens by mechanical instrument to measure range of motion (ROM) of L_2,3,L_3,4,L_4,5 intervertebral space and the overall ROM of L_2-5 lumbar vertebrae. Results MALC of lumbar vertebra was designed by 3D printing,and its component artificial vertebrae and upper and lower artificial end plates were manufactured. The semi-spherical structure was fabricated by precision lathe using high-crosslinked polyethylene material,and the prosthesis was assembled. Postoperative AP and lateral X-rays of lumbar vertebra at 6 months showed the implant position of implant and MALC were good without displacement and dislocation. In vitro biomechanical test of lumbar vertebrae specimens:(1) There were no statistical significance in ROM of lumbar intervertebral space flexion and extension,lateral flexion and rotation on L_3,4 and L_4,5,between non-fusion group and control group (P>0.05),while ROM of fusion group was significantly reduced compared with the other two groups (P<0.05). There were no significant difference in ROM of L_2,3 intervertebral flexion and extension,lateral flexion and rotation between non-fusion group and control group (P>0.05),while fusion group was significantly increased compared with the other two groups (P<0.001). (2) There was no significant difference in overall lumbar ROM of L_2-5 (P> 0.05). Conclusion The individual MALC could restore intervertebral height of lumbar vertebra while maintaining the stability of lumbar vertebra and re-establishing motor function of lumbar space.