Pain
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The basic pathophysiologic mechanisms related to disc herniation and sciatica are poorly understood. Recently it was demonstrated that nucleus pulposus from an intervertebral disc could induce structural and functional changes in adjacent nerve roots when applied epidurally, however, it is not known if such changes are painful. ⋯ However, the combination of disc puncture and displacement induced a reduction of the threshold for thermal stimulation, indicating hyperalgesia, that was present 2 days after surgery and gradually recovered during a 14-day period. These data and the associated description of this new model for experimental disc herniation may increase our understanding of the pathophysiologic events leading to sciatica and help in evaluating new modalities for diagnosis and treatment of disc herniation and sciatica.