A Comparison of the Lumbar Intervertebral Disc Mechanical Response to Normal and Impact Loading Conditions.
J Biomech Eng. 2013 Jun 1;
Authors: Jamison Iv D, Cannella M, Pierce E, Marcolongo M
Thirty-four percent of high speed craft personnel in the US Navy suffer from a reported lower back injury and low back pain, compared with 15 to 20% of the general population. Many of these injuries are related specifically to the intervertebral disc, including discogenic pain and accelerated disc degeneration. Numerous studies have characterized the mechanical behavior of the disc under normal physiological loads, while several have also analyzed dynamic loading conditions. However, the effect of impact loads on the intervertebral disc – and their contribution to the high incidence of low back pain – is still not well understood. An ex-vivo study was performed to investigate the mechanical response of the lumbar intervertebral disc to impact loading conditions. Impacts of 80 ms in duration saw a 18-21% rise in stiffness and 3-7% drop in energy dissipation compared to the 1 s baseline, signaling an abrupt change in disc mechanics. This likely causes more load to be transferred directly to the endplates, vertebral bodies, and surrounding tissues, which could potentially be a cause of low back pain. Determination of a “safety range” for impacts could result in a better refinement of design criteria for shock mitigating devices on high-speed craft.
PMID: 23775506 [PubMed – as supplied by publisher]