Karataglis D, Kapetanos G, Lontos A, Christodoulou A, Christoforides J, Pournaras J
First Orthopaedic Department, Aristotelian University of Thessaloniki, G. Papanikolaou General Hospital, 57010 Exohi, Thessaloniki, Greece.
J Bone Joint Surg Br. 2006 May;88(5):692-5. doi: 10.1302/0301-620X.88B5.17422.
The aim of this biomechanical study was to investigate the role of the dorsal vertebral cortex in transpedicular screw fixation. Moss transpedicular screws were introduced into both pedicles of each vertebra in 25 human cadaver vertebrae. The dorsal vertebral cortex and subcortical bone corresponding to the entrance site of the screw were removed on one side and preserved on the other. Biomechanical testing showed that the mean peak pull-out strength for the inserted screws, following removal of the dorsal cortex, was 956.16 N. If the dorsal cortex was preserved, the mean peak pullout strength was 1295.64 N. The mean increase was 339.48 N (26.13%; p = 0.033). The bone mineral density correlated positively with peak pull-out strength. Preservation of the dorsal vertebral cortex at the site of insertion of the screw offers a significant increase in peak pull-out strength. This may result from engagement by the final screw threads in the denser bone of the dorsal cortex and the underlying subcortical area. Every effort should be made to preserve the dorsal vertebral cortex during insertion of transpedicular screws.
这项生物力学研究的目的是探讨椎体背侧皮质在椎弓根螺钉固定中的作用。将莫斯椎弓根螺钉植入25具人类尸体椎骨的每个椎体的双侧椎弓根。在一侧去除与螺钉入口部位对应的椎体背侧皮质和皮质下骨，另一侧予以保留。生物力学测试表明，去除背侧皮质后，植入螺钉的平均峰值拔出力为956.16N。若保留背侧皮质，平均峰值拔出力为1295.64N。平均增加量为339.48N（26.13%；p = 0.033）。骨密度与峰值拔出力呈正相关。在螺钉植入部位保留椎体背侧皮质可显著提高峰值拔出力。这可能是由于最终的螺钉螺纹与背侧皮质和下方皮质下区域的较致密骨啮合所致。在植入椎弓根螺钉时应尽一切努力保留椎体背侧皮质。
