牵引对颈椎稳定性影响的生物力学研究

目的：探讨不同牵引重量对颈椎稳定性的影响。方法：采用五具意外伤亡的新鲜尸体颈椎标本（Ｃ１～７）先后制成正常和Ｃ５－６椎间盘部分切除的颈椎生物力学模型，运用生物力学电测技术观察不同牵引重量对颈椎稳定时的总体位移和椎间盘位移的影响。结果：７５Ｎ压缩载荷下，切除组比正常组的压缩载荷－位移增加２７％（Ｐ＜０．０１），椎间盘膨出位移增加５９％（Ｐ＜０．０１）。牵引下颈椎压缩载荷－位移转向拉伸载荷－位移，其在两组中均随着牵引量的增加而增加。前屈１５度４，６，８ｋｇ牵引下，切除组比正常组的位移分别增加２２％，７％，１７％（Ｐ＜０．０５），椎间盘位移也呈类似变化。牵引后的二种位移增加幅度以４～６ｋｇ时较适度。结论：椎间盘急慢性损伤后，颈椎稳定性下降，对部分颈椎病患者采用轻度前屈位４～６ｋｇ的牵引方法，符合颈椎的生物力学原理。

Biomechanical study on stability of cervical spine by cervical traction

Objective:To experimentally study the effect of cervical traction with different forces on cervical stability.Mehtods:The cervical biomechanical models of normal spines and spines with discoidectomy(of C5-6) were made from sample of C1-7 in 5 fresh cadavers of accidental death.The effect of cervical traction with different forces on whole spine displacement and disc displacement was determined with electric biomechanics measure technique.Results:Under 75 N compression,the compression-displacement and disc bulging-displacement of the spine with discoidectomy was respectively increased by 27% and 59% when compared with those of normal spine.The value of spine compression-displacement turned to stretch-displacement was enhanced with the increase of traction force in both groups.Under the 4,6,8kg traction with forward flexion,the displacement of spine with discoidectomy was respectively increased by 22%,7%,17%(P<0.05),compared with the normal spines;while the bulging-displacement of disc was also similar.Conclusion:It is indicated when the disc is suffering from injuries either acute or chronic stage, the cervical stability is reduced.To some patients,the cervical traction with 4-6kg and small forward flexion is more suitable to the principle of biomechanics of human cervical spines.