Arianna Reay, Aubrie Taylor, Brigham Young University
Degenerative Disc Disease is a common and even debilitating source of back pain. A common treatment for low back pain is spinal fusion, which involves two separate surgeriesÛÓone anterior, the other posteriorÛÓin which the patientÛªs degenerated disk is removed and replaced by bone graft. Current surgeries typically employ the use of thick screws, which are destructive to the vertebrae and must be installed posteriorly because they are unable to maintain stability in the mostly porous material of the vertebral body. Success and patient satisfaction rates with spinal fusion are comparatively low, and recent research suggests that after spinal fusion, neighboring spinal disks begin to degenerate more quickly. Our research involves the mechanical testing of a novel, compliant-mechanism vertebral clamp that would be used to attach anteriorly to the vertebral body, enabling a single surgery approach to spinal treatment that does not permanently damage the vertebrae. We hypothesize that the clamp can maintain secure fixation under the severe loading of the lumbar spine by attaching to the anterior side of the vertebral bodyÛªs sturdy cortical shell without penetrating the delicate, porous interior. Our research involves the mechanical testing of this clamp in the primary modes of spinal loading (compression, lateral bending, extension and flexion, and axial rotation). Loads are applied using a custom spine tester that maintains the segmental instantaneous screw axis and allows for the application of a compressive follower load to simulate the dynamic muscle forces and torso weight imposed upon lumbar spine during activities of daily living. The clamp will be tested in isolation to validate the analytical and numerical models used in its design. Subsequently, it will be tested when attached to a vertebrae to measure fixation strength during spinal motion. This work paves the way for future pre-clinical and clinical testing.