医用骨水泥对腰椎椎弓根钉固定的影响

目的探讨医用骨水泥对椎弓根钉固定强度的影响。方法24个新鲜冰冻尸体的腰椎椎体作为实验对象,随机分为3组,第1组为单纯钻孔组,第2组丝锥攻丝组,第3组为扩大钻孔组。每组8个椎体,每个椎体自身对照,两侧的固定方式一样,只是一侧在固定螺钉前加用骨水泥,另一侧不加骨水泥作为对照。固定后分别在万能机上进行轴向拉力测试,比较二者的差异。结果在第1组单纯钻孔组中,骨水泥固定侧拉力范围平均(1988±289)N,对照侧平均(1242±264)N,二者比较有显著差异(P<0001)。第2组丝锥攻丝组骨水泥固定侧拉力范围平均(4553±945)N,对照侧为平均(1303±138)N,二者比较有显著差异(P<0001)。第3组扩大钻孔组骨水泥固定侧拉力范围平均(4653±675)N,对照侧平均1213N,二者比较有显著差异(P<0001)。3组骨水泥固定侧的结果相比,第1组单纯钻孔组与第2组丝锥攻丝组、第3组扩大钻孔组之间有明显差异(P<0001),而第2组与第3组之间无差异(P>005)。结论骨水泥对椎弓根螺钉的固定有明显的增强作用。对于骨质疏松的患者或手术中椎弓根钉固定失败,或二次手术重新固定时,都可以采取骨水泥进行加强固定的方法,且强度可靠。

Effect of pedicle screw fixation with bone cement in lumbar

Objective To evaluate the strength of pedicle screw fixation with bone cement in human cadaveric lumbar vertebral bodies by using biomechanical test. Methods Twenty four fresh frozen cadaveric lumbar vertebral bodies were randomly divided into 3 groups, which each group had 8 bodies. The bodies in the first group were drilled only. The bodies in the second group were drilled with tap. The bodies in the third group were drilled and the holes were enlarged by borer. Each vertebral body was drilled in both right and left sides, which one side served as control with the pedicle screws fixation only and another side served as testing side with the pedicle screw fixation with bone cement. The pullout strength was tested on both sides by using borer. Result There was significant difference of manifestation of pull strength between the control side and the testing side in all groups ( P <0.001). For the manifestation of pull strength of testing side in different groups, which had pedicle screw fixation with bone cement, there was no significant difference between the second group and third group, however, the difference between the first group and the second group and between the first group and third group were significant. Conclusion The pedicle screws with bone cements could significantly enhance the strength of fixation in cadaveric lumbar compared with pedicle screws only.