The mechanism of low back pain is believed to involve a mechanical component. However, there is an incomplete understanding of the local mechanical response of neural tissue and no defined threshold of mechanical loading of individual tissue structures for pain onset and maintenance. While animal models are presently used to examine radiculopathy, the extent of damage to the lumbar nerve roots, dorsal root ganglia ~ nerves in these models remains solely qualitative in nature. It is the broad aim of this work to examine mechanical factors influencing local tissue injury in a rat model of lumbar radiculopathy by (1) characterizing the time course of local tissue mechanics and the associated pain response for loading to the lumbar nerve root, dorsal root ganglion, and spinal nerve, (2) quantifying the differences in mechanical and physiologic responses for ligation of the lumbar nerve root using loose, tight, and chromic gut sutures, (3) determining compression load thresholds for onset and maintenance of a pain response. Mechanical tissue deformation data will be acquired by imaging at the time of injury and at time points following surgery. age analysis will be used to determine the local strain tensor for particular tissue components. Tissue bins will be correlated with mechanical allodynia and neuroimmune mediators of persistent pain.
