EFFECTS OF BONE-MINERAL DENSITY ON PEDICLE SCREW FIXATION
EFFECTS OF BONE-MINERAL DENSITY ON PEDICLE SCREW FIXATION
复制标题
DOI：
10.1097/00007632-199411000-00008
复制
发表时间：
1994-11-01
期刊：
影响因子：
3
通讯作者：
COOK, SD
中科院分区：
文献类型：
--
作者：
HALVORSON, TL;KELLEY, LA;COOK, SD
研究设计。为了评价骨密度对腰椎椎弓根螺钉固定质量的影响，我们测定并比较了正常腰椎和骨质疏松症患者腰椎的轴向拔出力。对四种螺钉孔制备工艺进行了评价。我们还评估了两种椎弓根螺钉/偏置椎板钩结构，以确定椎板钩的辅助固定是否能将固定质量提高到足以用于骨质疏松症腰椎的水平。采用其中一种技术将椎弓根螺钉插入新鲜冷冻的尸体脊柱。然后在单轴试验架上通过拉拔来评估固定强度。骨矿物质密度对轴向拔出力有很大影响。在正常骨中，螺钉孔准备方法对固定质量无明显影响。然而，在骨质疏松的脊柱中，未使用螺钉孔或用5.5 mm螺钉攻螺钉孔均可提高拔出力，统计学意义显著（P < 0.003）。此外，在相邻的两个节段使用带偏移钩的椎弓根螺钉可显著改善固定效果，将拔出力提高到预期值的两倍。椎弓根螺钉拔出强度与骨密度高度相关。用神经节刀进行5.5毫米的敲击或准备，可提高拉拔强度。椎弓根螺钉与两节段椎板钩联合使用可提高拉出强度。
Study Design. In an attempt to evaluate the effects of bone mineral density on the quality of fixation of pedicle screws in the lumbar spine, the axial pullout force was determined and compared in normal and osteoporotic human lumbar spines.Objectives. Four techniques of screw hole preparation were evaluated. Two pedicle screw/offset laminar hook constructs also were evaluated to determine whether the adjunct fixation of the laminar hooks would improve quality of fixation to a level sufficient to allow their use in the osteoporotic lumbar spine.Methods. Pedicle screws were inserted by one of the listed techniques into fresh frozen cadaveric human spines. The fixation strength then was evaluated by pullout on a uniaxial testing frame.Results. Bone mineral density was a strong influence on axial pullout force. In normal bone, the method of screw hole preparation did not significantly affect the quality of fixation. However, in the osteoporotic spine, either an untapped screw hole or the tapping of a screw hole with a 5.5 mm tap improved the pullout force a statistically significant amount (P < 0.003). Also, a pedicle screw with offset hooks at two adjacent levels improved the fixation significantly, increasing the pullout force to twice the expected value.Conclusion. Pedicle screw pullout strength was highly correlated with bone mineral density. A 5.5 mm tap or preparation with a ganglion knife improved pullout strength. Use of pedicle screws in conjunction with laminar hooks at two levels improved pullout strength.