【摘要】 目的:比较两种胸椎椎弓根根外固定方法与经椎弓根固定方法的螺钉拔出强度,评价胸椎椎弓根根外固定的生物力学效果。方法:新鲜胸椎标本4具,共32个肋骨-椎骨序列,根据螺钉固定方法不同分为3组,A组采用经椎弓根固定,B组采用经横突-椎体固定,C组采用经改良肋横突法固定。根据所用螺钉规格不同将其分为4种不同测试条件:D1,螺钉直径5.5mm,长度40mm;D2,螺钉直径5.5mm,长度45mm;D3,螺钉直径6.5mm,长度45mm;D4,螺钉直径6.5mm,长度50mm。测试3种固定方法下的螺钉拔出力,并做统计学分析对比。结果:D1条件下A组拔出力为787.0±119.3N,B组为706.2±109.4N,C组为616.1±82.3N,3组间比较有显著性差异(P<0.01);D2条件下A组拔出力为862.3±128.7N,B组为811.4±113.6N,C组为655.1±92.2N,A、B组间比较无显著性差异(P>0.05),A、B组与C组比较有显著性差异(P<0.01);D3条件下,A组拔出力为855.3±117.1N,B组为938.0±131.5N,C组为861.3±117.8N,A、C组间比较无显著性差异(P>0.05),A、C组与B组比较有显著性差异(P<0.01);D4条件下A组拔出力为864.3±120.9N,B组为959.6±135.2N,C组为941.2±115.4N,A组与B、C组比较均有显著性差异(P<0.01),B、C组间比较无显著性差异(P>0.05)。结论:使用直径6.5mm、长度45～50mm的螺钉固定时,胸椎椎弓根根外固定螺钉拔出力优于椎弓根固定,有较好的生物力学效果。更多还原

【Abstract】 Objective:To compare the screw pull-out strength between two extrapedicular instrumentations and transpedicular instrumentation and to evaluate their biomechanical effect.Method:Four fresh thoracic specimens with a total of 32 rib-pedicle units were divided into three groups according to different fixation:transpedicular technique(group A),the transverse process-vertebra(group B),modified costre-transverse process(group C).4 conditions defined as:group D1 with the screw diameter of 5.5mm and length of 40mm;group D2 with screw diameter of 5.5mm and length of 45mm;group D3 with screw diameter of 6.5mm and length of 45mm;group D4 with screw diameter of 6.5mm and length of 50mm were added in each group,the pull out forces of the screws in three different techniques(group A,B and C) were tested and compared separately.Result:Under D1 condition,the transpedicular technique(group A) had the higest pullout force of 787.0±119.3N,significant difference was found between transpedicular group and the two extrapedicular groups(P<0.01).Under D2 condition,the group A has the highest pullout force of 862.3±128.7N,but no significant difference was found in three methods(P>0.05).Under D3 condition,group B had the highest pullout force of 938.0±131.5N,group A had the minimum pullout force of 855.3±117.1N,and significant difference was found between them(P<0.05).Under D4 condition,the two extrapedicular methods had the highest pullout force,and significant difference was found in extrapedicular and transpedicular methods(P<0.05).Conclusion:With the screw of 6.5mm in diameter and 45mm or 50mm in length,the extrapedicular method has the higher screw pullout force than transpedicular method can supply.更多还原