Investigation of the Mechanical Response of the Anterior and Posterior Cervical and Lumbar Disc Bulge

The spine is an important structure that provides support, flexibility, range of motion and protection. Neck and lower back pain are significant problems in the aging population. In this dissertation the cervical and lumbar intervertebral disc bulge response to compressive forces will be analyzed. Eleven cervical specimens and seven lumbar specimens are compressed in a series of three cycles with increasing loads to 550 N. The vertical deformation and anterior bulge is measured in multiple configurations including intact, laminectomy, and facetectomy the posterior bulge is also measured in the latter two configurations. The changes in the bulging patterns are compared and analyzed. It is shown that as the cervical specimens were compressed stiffening affect in the anterior bulge occurs that did not appear in the vertical deformation response. Upon further investigation, using the laminectomy configuration to gain access to the posterior Intervertebral Disc (IVD) region, it was found that the posterior bulge did not experience a stiffening effect. Additionally, when the articular facets were removed to assess the changes that the articular facets impose on the anterior and posterior disc bulge, it was shown that a translation of the vertebral bodies occurs in the cervical and lumbar regions but in opposite directions suggesting that the orientation of the articular facets may play a role in the deformation response of the IVD. The results from this study can be used as a basis for further studies to develop diagnostic techniques for spinal injuries and ailments like herniation, spondylolisthesis, among others.