聚乙烯醇水凝胶人工髓核置入对腰椎运动影响的生物力学研究

目的：研究髓核摘除后聚乙烯醇水凝胶人工髓核置入对腰椎活动度和椎间隙高度的影响.方法：对7具新鲜成人尸体L4/5正常椎间隙、髓核摘除后和置入人工髓核后在8.0Nm扭矩下的屈伸、侧弯和旋转的活动度（ROM）、中性区（NZ）和椎间隙高度变化进行测试、比较.结果：髓核摘除后,L4/5椎间屈伸、侧弯、旋转的ROM和NZ较正常组显著增加（P＜0.05或0.01）,在0和200N的负荷下椎间隙高度较相同情况下正常组分别下降1.2mm和1.7mm;置入人工髓核后,相对于正常椎间隙,L4/5椎间屈伸、侧弯、旋转的ROM和NZ无明显差异,较髓核摘除组明显下降（P＜0.05或0.01）,在0N和200N的负荷下椎间隙高度较相同情况下髓核摘除组分别增加1.6mm和2.0mm.结论：聚乙烯醇水凝胶人工髓核置入椎间盘切除后的椎间隙可有效恢复椎间隙高度,维持腰椎节段正常的三维运动功能稳定性.

Biomechanical research of the effect of polyvinyl alcohol hydrogel prosthetic disc nucleus on lumbar kinematic behaviour

Objective:To study the effect of prosthetic disc nucleus on the three-dimensional kinematic behaviour and disc height of L4/5.Method:Seven adult human cadaveric lumbar motion segments were loaded with moments of 8.0Nm in flexion-extension,lateral bending,and axial rotation,changes of disc heigh,range of motion(ROM) and neutral zone(NZ) were measured at L4/5 lumbar spine following insertion of device and the results were compared with that under intact state.Under the preload of 200N,change of disc height from the intact state was measured after nucleotomy and device implantation.Statistical significance in ROM and NZ was determined using repeated measures analysis of variance(ANOVA) analysis.Result:The nucleotomy significantly increased ROM,NZ and reduced disc height compared with the intact state,the insertion of prosthetic disc nucleus restored the ROM,NZ to the intact.Original intact disc height was received after implantation of the device.Conclusion:The device can potentially restore the stability and disc height after nucleotomy and retain the motion segment of lumbar spine.