颈伸肌群对颈椎间盘和小关节内压力变化的影响

Role of cervical extensor muscles in pressure alterations of intervertebral disc and facet joints

目的：颈椎周围肌群是维系颈椎关节稳定和功能的动力系统，其性能改变对颈椎病发生发展具有重要意义。实验拟观察新鲜颈椎标本椎间盘和小关节内压力变化，探讨颈周肌群在颈椎发病机制中的作用。方法：①实验材料：实验于2005-03／07在上海中医药大学附属岳阳中西医结合医院推拿生物力学实验室完成。5具新鲜尸体颈椎结构标本由原解放军第一军医大学提供。②实验方法：将C3-4、C4-5、C5-6、C6-7，的颈椎间盘前缘和关节突关节C3-4、C4-5、C5-6、C6-7等处同时埋置8个微型压力传感器，并应用模拟颈伸肌正常生理段性能的弹簧。③实验评估：观察颈椎结构包括颈伸肌等在颈椎活动时的压力变化情况。结果：随前屈角度的增加，颈椎间盘内的压力和颈伸肌的拉力明显增加。而随后伸角度的增加，小关节内的压力明显增加。加载模拟伸肌后，椎间盘和小关节的压力明显减低。结论：颈伸肌群分担了一部分颈椎载荷，屈颈几率和强度的增加是颈椎病发生发展的关键因素。

AIM： Cervical muscles are power system for neck physiologic function and structure stabilization, and their pathological changes or dysfunction may result in cervical spondylosis. This study investigated the role of cervical muscles in cervical spondylosis by observing the alterations of fresh cervical vertebrae intervertebral cartilage and facet joint intra-articular pressure. METHODS： （1）The experiment was performed at Laboratory of Biomechanics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine from March to July 2005. Five samples of fresh cadaver cervical vertebrae were provided by previous First Military Medical University of Chinese PLA. （2）Eight micro-pressure transducers were embedded in the intervertebral disc and facet joints of C3-4, C45, C5-6, and C6-7. A spring was simulated as cervical extension muscles and the strength was measured when it was pulled. （3）Pressure changes were measured. RESULTS： The stress in the intervertebral discs of C3-4, C45, C5-6, C6-7 cervical spine increased obviously with the increasing of flexion degree. The pressure in the intervertebral facet joints in C3-4, C4-5, C5-6, C6-7 of cervical vertebrae increased remarkably with the increasing of extension degree. The pressure in intervertebral discs and facet joints significantly decreased under simulated extensor. CONCLUSION： Cervical extensor muscles share partial load of cervical vertebrae. Neck flexion rate and increase in strength are key factors for the prevalence of cervical spondylosis.