应用自制异种骨椎间融合器行颈椎前路椎体间融合的生物力学评价:即刻稳定效果及自身强度

Biomechanical evaluation on anterior approach for cervical intervertebral fusion by self-made heterologous bone fusion cages:Immediate stability and self-strength

目的：自体髂骨移植与钛合金Cage在颈椎椎体间融合手术中的应用存在较多并发症,为弥补其不足,自行研制出一种并发症少的生物型融合器,通过在成人新鲜颈椎标本上模拟临床术式放置异种骨椎间融合器,验证其置入后的稳定性及自身强度。方法：实验于2005-06/2006-07在吉林大学机械科学与工程学院力学实验室完成。取16具新鲜成年男性C1～7颈椎标本,分为3组：①正常组：完整C1～7。②对照1组：模拟前路间盘C5～6摘除置1枚融合器。③对照2组：模拟前路间盘C5～6、C6～7摘除置2枚融合器。3组均进行稳定性实验和黏弹性实验,观察在不同应力下前屈、后伸、垂直压缩、扭转时位移距离,颈椎移位时融合器最大拔出力,脊柱压缩应力与时间,脊柱施加应力后时间与应变量。结果：①在颈椎前屈及后伸状态下对照1,2组较正常组位移小但差异不显著（P〉0.05）。②垂直压缩实验结果显示在最大载荷为500N力作用下对照1,2组位移较正常组小,但差异不显著（P〉0.05）。③颈椎移位时拔出力实验结果表明,植入椎间的融合器最大拔出力为1.85kN。④在200N·cm扭矩作用下,对照1,2组扭转角较正常组小,但差异不显著（P〉0.05）。⑤对照1,2组7200s,应力松弛量和蠕变量小于正常组,但差异不显著（P〉0.05）。结论：自制异种骨椎间融合器具有足够的支撑、抗滑、维持或增加椎间隙高度的功能,符合生物力学及临床要求。

AIM： Autologous lilac bone transplantation and titanium alloy can induce many complications of cervical intervertebral fusion operation, thus a biological fusion cage is made to imitate the heterologous bone fusion cage in adult fresh cervical vertebra, and the immediate stable effects and self-strength of the heterologous bone fusion cages are verified. METHODS： The experiment was carried out in the Laboratory of Mechanics, Mechanical Science and Engineering Institute of Jilin University from June 2005 to July 2006. The cervical vertebrae C1_7 were obtained from sixteen fresh adult male corpse and divided into three groups： ①normal group： intact C1-7 cervical vertebrae. ②A control group： C5-6 intervertebral disc were imitated to be removed through anterior approach and placed with a fusion cage. ③B control group： C5-6 and C6-7 intervertebral discs were imitated to be removed through anterior approach and placed with two fusion cages. Stability test and visco-elasticity test were all performed in three groups, then the dislocation distance of anterior flexion, backward extension, left and right torsion and axial compression under different stresses were measured. The maximum pull strength of fusion cage at vertical dislocation, the stress and time of spinal compression, and the time and dependent variable after spinal stress were also assayed. RESULTS： ①The dislocation of fusion cages were slighter than that of normal group, no matter implanting one or two fusion cages when the cervical vertebrae were at anterior flexion or backward extension, but the difference was not significant （P 〉 0.05）. ②The result of vertical compression showed that, the dislocation of control groups was less than that of normal group under the maximum loading of 500 N, but the difference was not significant （P 〉 0.05）.③The result of cervical vertebrae pull test showed that, the maximum pull strength was 1.85 kN when the fusion cage was implanted in the vertebrae at dislocation. ④The torsion angle of control groups was smaller than that of normal group when the torsion strength was 200 N.cm, but the difference was not significant （P〉 0.05）. ⑤Compared with normal group, the stress relaxation and creep functions of control groups at 7 200 S were decreased, but no significant difference was found （P 〉 0.05）. CONCLUSION： Heterologous bone fusion cages can provide enough support and anti-sliding ability, remain or increase the height of intervertebral spaces. It completely consistents with clinical and biomechanical requirements.