髂骨垫片对髂骨螺钉疲劳载荷后下沉位移的影响  

Effect of an iliac bone plate on the subsidence of iliac screw after fatigue loading

作　　者：于滨生[1] 曾丽雯[1] 李泽民[1] 周治宇[1] 王丽冰[1] 

机构地区：[1]中山大学附属第一医院脊柱外科骨科研究所,广州市510700

出　　处：《中国脊柱脊髓杂志》2011年第7期588-591,共4页Chinese Journal of Spine and Spinal Cord

基　　金：广东省科技计划项目(编号:2008B050100012;2009B050700023)

摘　　要：目的：评价自主设计的髂骨垫片对髂骨螺钉疲劳载荷后下沉位移的影响。方法：6具成人新鲜尸体腰椎-骨盆标本用于实验。经双能X线吸收法测定L1L4平均骨密度后,随机将髂骨垫片放置在一侧髂骨进钉点处（A组）,另一侧无垫片作为对照（B组）。将直径7.5mm、长度70mm的髂骨螺钉分别置入左右侧髂骨,在MTS材料实验机上,向螺钉尾部施加100400N垂直循环载荷20000次,记录每5000次载荷后两侧髂骨螺钉的下沉位移并比较。结果：6具标本的腰椎骨密度为0.781.06g/cm2,平均0.89±0.06g/cm2。所有螺钉顺利承受20000次的垂直载荷。在第5000、10000、15000和20000次轴向压缩载荷点上,A组髂骨螺钉的下沉位移分别为0.28mm、0.36mm、0.48mm和0.66mm;B组髂骨螺钉的下沉位移分别为0.34mm、0.69mm、0.88mm和1.07mm。在第5000次载荷点上,A组和B组螺钉下沉位移的差异无显著性（P〉0.05）;在第10000、15000和20000次载荷点上,A组与B组螺钉下沉位移的差异均有显著性（P〈0.05）。20000次载荷后X线片发现A组无螺钉松动,B组5枚螺钉松动。结论：髂骨垫片可有效减少髂骨螺钉疲劳载荷后的下沉位移,防止髂骨螺钉松动。Objective：To evaluate the biomechanical effect of a self-designed iliac bone plate on the subsidence of iliac screw after fatigue loading.Method：Lumbo-pelvic specimens from 6 adult fresh cadavers were used in this study,their mean bone mineral densities（BMD） of L1-L4 were measured by using dual-energy radiograph absorptiometry.The iliac bone plate was randomly placed at the iliac screw entry point of one-side ilium（group A）,while the other side without iliac bone plate served as the control（group B）.Then,the iliac screws with 70mm length and 7.5mm diameter were inserted into the ilium bilaterally.On a MTS testing machine,a dynamic compressive loading of 100-400N was added to the screw head for 20000 cycles.The screw subsidence displacements following each 5000 cyclic loadings were measured and compared between two groups.Result：The average BMD value of 6 specimens was 0.89±0.06g/cm2,ranged from 0.78g/cm2 to 1.06g/cm2.All the screws passed the 20000 cyclic loadings smoothly.At the time-points of the 5000th,10000th,15000th,and 20000th cyclic loadings,the subsidence displacements of iliac screw in group A were 0.28mm,0.36mm,0.48mm and 0.66mm respectively;while those in group B were 0.34mm,0.69mm,0.88mm and 1.07mm respectively.After the first 5000 cyclic loadings,no significance with respect to subsidence displacement was detected between two groups（P〉0.05）.However,at the 10000th,15000th and 20000th cycles,significant difference was noted between two groups（P〈0.05）.After the 20000 cyclic loadings,no screw in group A and 5 screws in group B were found loosen under radiograph.Conclusion：The iliac bone plate can effectively resist the subsidence of iliac screw following fatigue loading and protect iliac screw against loosening.

关 键 词：脊柱-骨盆固定 髂骨螺钉 髂骨垫片 生物力学 

分 类 号：R318.01[医药卫生—生物医学工程]