A novel rodent neck pain model of facet-mediated behavioral hypersensitivity: implications for persistent pain and whiplash injury

Clinical, epidemiological, and biomechanical studies suggest involvement of cervical facet joint injuries in neck pain. While bony motions can cause injurious tensile facet joint loading, it remains speculative whether such injuries initiate pain. There is currently a paucity of data explicitly investigating the relationship between facet mechanics and pain physiology. A rodent model of tensile facet joint injury has been developed using a customized loading device to apply two separate tensile deformations ( low, high; n=5 each) across the C6/C7 joint, or sham ( n=6) with device attachment only. Microforceps were rigidly coupled to the vertebrae for distraction and joint motions tracked in vivo. Forepaw mechanical allodynia was measured postoperatively for 7 days as an indicator of behavioral sensitivity. Joint strains for high (33.6±3.1%) were significantly elevated ( P