Biomechanics of Human Cervical Spinal Column Under Physiologic Loads

Abstract

Abstract The determination of the biomechanics of the human cervical spinal column under physiologic loads was a focus of the present study. The effects of pre-load on the load carrying capacity of spine were investigated. Structural morphology was divided into young, representing normal/non-degenerated, and old, representing abnormal/degenerated spines. Intact human cadaver cervical spinal columns were carefully isolated by maintaining the integrity of the ligamentous soft tissues. Fat and surrounding musculature were dissected. Radiographs of the specimens were obtained before the test. At each level of the cervical column, retroreflective targets were inserted into the bony articulations. Kinematic information was obtained from these targets. Principles of continuous motion analysis were used to determine the kinematics of the cervical column. A six-axis load cell was attached at the inferior end of the specimen. Flexion, extension, axial rotation, and lateral bending moments were applied. The specimens were tested with and without pre-load conditions. Results are presented with regard to variations in angular stiffness values as function of applied moment, pre-load, and spine condition. This study emphasizes the differing roles contributed by the load vector and specimen morphology on cervical spine biomechanics.