摘要
目的:探讨椎弓根内固定置钉方法改进后的生物力学性能。方法:实验于2001-12/2002-12在上海科技大学生物力学实验室完成。采集成人湿润固定的胸腰椎标本6具,12个功能节段,采用咬除进针点周围5mm的骨皮质和保留骨皮质,由开路器准备钉道两种方法。拔出试验中,实验组去皮质范围为约5mm,对照组为保留骨皮质。采用Magerl定位法,进针方向与矢状面呈5°～15°。然后,进行Steffee椎弓根器械内固定,采用直径为6mm的螺钉。用实验应力分析法比较其脊柱的强度和刚度等生物力学性能。测试仪器采用WD-5万能试验机和NT-100B扭转试验机。结果:对两类标本进行应变-强度分析,位移-刚度分析脊柱在轴向中心压缩、前屈、后伸、侧屈及扭转状态下系统分析结果表明:咬除进针点部分骨皮质,探明骨道,置钉准确,坚强有效的固定与未咬除骨皮质标本的强度和刚度差异无显著性意义(P>0.05)。试验中也看到,如果去皮质的范围过大,将会降低拔出力(P<0.05)。结论:进钉点咬除部分骨皮质行椎弓根内固定,对脊柱的强度和刚度无明显影响,手术方法安全,简单,实用,但应注意咬除皮质的范围不应超过螺钉的直径,否则会降低拔出力。
AIM:To investigate the biomechanical characteristics of hole preparation metho d for transpedical internal fixation. METHODS:The experiment was conducted in the Laboratory for Biomechanics,Shangh ai University of Science and Technology from December 2001 to December 2002.Twel ve functional spinal units were selected from thoracolumbar spine specimens of 6 adult cadavers fixed damply.The 12 functional spinal units were divided into tw o groups:5 mm of the posterior cortex was bitten away in the study group and the posterior cortex remained in the control group.The path opener was used to prep are the two methods for screw fixation.The screw was inserted with the method of Magerl localization in the 5-15°direction.Then,the bilateral Steffee instrume ntation with 6 mm diameter pedicle screws was implanted.Finally,the biomechanic al characteristics of strength and stiffness of spinal column were tested by exp erimental stress analysis with multipurpose WD 5 and NT 100B torsion tester. RESULTS:As shown in the analysis for strain strength of two specimens,and ana lysis for displacement stiffness in the spinal central axial direction,compress ion,anterior flexion,posterior bending,lateral bending,axial torsion,the strengt h and stiffness of spinal column between the posterior cortex bitten away and po sterior cortex remained had no significant difference after the correct path ope ning,exact screwing and effectively tough fixation(P >0.05).It was also found th at the pull out strength would be decreased if the bone cortex was removed more extensively(P< 0.05). CONCLUSION:The internal fixation for the bitten away insertion point of poste rior bone cortex has no effects on the strength and stiffness of spinal column.T he method for fixation is a safe,simple and practical method for stabilizing a s pinal motion segment,but it is noticed that the scope of biting away the posteri or cortex should not exceed the diameter of screw in order to avoid decreasing t he pullout force.
出处
《中国临床康复》
CSCD
北大核心
2005年第2期60-62,共3页
Chinese Journal of Clinical Rehabilitation
