Stress management...mechanics and mechanobiology of the intervertebral disc

The intervertebral disc (IVD) plays a central role in spinal function, serving as a unique joint that cushions loads and simultaneously enables flexibility and stabilizes motion segments. In healthy discs, the chief mechanism for fulfilling this role is through pressurization of the nucleus pulposus (NP), which consequently places the annulus fibrosus (AF) in tension. Cellular and biochemical changes that occur during aging compromise NP function and lead to greater susceptibility to degenerative disc disease (DDD). Although it is believed that spinal loading has at least a contributory, if not pivotal, influence on aging and disease, the precise role of mechanical stress is not yet clear. One area on which we have focused our efforts has been to examine how hypothetical variations in daily loading might influence the IVD, from both mechanical and mechanobiologic perspectives. Using a combination of computational, analytical, and experimental techniques, we have demonstrated that load history of the IVD plays a critical role in intradiscal pressure generation. Based on these findings, we have developed a theoretical framework to guide our current in vivo and in vitro studies toward non-invasive and biologics-oriented interventional therapies against DDD.