[A biomechanical study on cervical spinal posture and prior loading history affecting spinal compressive strength].
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 (C3,4 and C5,6). 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.


CONCLUSIONS
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.
Ma
Xun
X
Department of Orthopaedics, Second Hospital, Shanxi Medical University, Taiyuan 030001, China.
Li
Qin-liang
QL
Fan
Yong-gui
YG
D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000293:injuries / Q000502:physiology*; D019245:Compressive Strength; D006801:Humans; D066298:In Vitro Techniques; D011187:Posture; D016474:Weight-Bearing