Biomechanics of the cervical spine 4: major injuries.

This review presents considerations regarding major cervical spine injury, including some concepts that are presently undergoing evaluation and clarification. Correlation of certain biomechanical parameters and clinical factors associated with the causation and occurrence of traumatic cervical spine injuries assists in clarifying the pathogenesis and treatment of this diverse group of injuries. Instability of the cervical column based on clinical and mechanistic perspectives as well as the role of ligaments in determining instability is discussed. Patient variables such as pre-existing conditions (degenerative disease) and age that can influence the susceptibility or resistance to injury are reviewed. Radiological considerations of major injuries including dynamic films, CT and MRI are presented in the diagnosis and treatment of cervical trauma. Specific injury patterns of the cervical vertebral column are described including attention to the relative mechanisms of trauma. From a biomechanical perspective, quantification of injury tolerance is discussed in terms of external and human-related variables using laboratory-driven experimental models. This includes force vectors (type, magnitude, direction) responsible for injury causation, as well as potential influences of loading rate, gender, age, and type of injury.