颈脊柱姿势及预负荷史对压缩强度影响的生物力学研究

A biomechanical study on cervical spinal posture and prior loading history affecting spinal compressive strength

目的研究颈脊柱姿势及预负荷对颈脊柱压缩强度的影响。方法选用12具成人健康新鲜尸体颈段脊柱,解剖出C3,4、C5,6共24个运动单位(包括上下两个椎体和椎间盘)。施以压缩负荷,观察两种预负荷状态(脱水和高度水化状态)和两种姿势(中立位和屈曲位)下,颈段脊柱的极限压缩强度。通过解剖和x线检查来明确颈椎的损伤。结果标本屈曲位时极限压缩强度比中立位时小(P<0001),在中立位损伤负荷下,高度水化状态标本的极限压缩强度比脱水状态标本低29%(P<001)。结论晨起椎间盘高度水化状态下以及颈脊柱屈曲位时,受到外伤负荷颈脊柱更易损伤。

Objective The purpose of this study is to investigate the effect of cervical spinal posture and prior loading history on spinal compressive strength. Methods Twelve human cadaver cervical spines were harvested and dissected into 24 motion segments containing 2 vertebrae and the intervertebral discs (C 3,4 and C 5,6 ). Compressive loads were applied on so that the effects of 2 loading conditions (dehydrated, superhydrated) and 2 postures (neutral trunk, flexed) could be examined. Dissection techniques and X rays were used to determine the tissue injuries. Results Specimens had a lower ultimate compressive strength ( P <0 001) in flexed posture than in neutral trunk posture. Under the injury loading in neutral trunk posture, superhydrated specimens had a lower strength (29%, P <0 01) than dehydrated specimens did. Conclusion The spine may be more prone to injury early in the morning when the discs are at highest level of hydration and the cervical spine is in fully flexed posture.