Spine
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The possibility to prevent nucleus pulposus-induced functional and structural nerve root injury by selective tumor necrosis factor-alpha inhibition was assessed in an experimental model in the pig spine. ⋯ The data clearly indicate that tumor necrosis factor-alpha is involved in the basic pathophysiologic events leading to nerve root structural and functional changes after local application of nucleus pulposus. The study therefore provides a basic scientific platform with potential clinical implications regarding the use of anti-tumor necrosis factor-alpha medication as treatment in patients with disc herniation and sciatica.
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An experimental study to clarify the effects of pentoxifylline, as an anti-tumor necrosis factor-alpha therapy on endoneurial fluid pressure in the dorsal root ganglion using an animal model of herniated nucleus pulposus. ⋯ Pentoxifylline, an anti-tumor necrosis factor-alpha drug, prevented the dorsal root ganglion compartment syndrome caused by topical application of nucleus pulposus. Anti-inflammatory cytokine therapy may become an effective treatment of sciatica due to disc herniation.
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The levels of dorsal root ganglions (DRGs) innervating the dorsal portion of the lumbar intervertebral discs from L1-L2 to L4-L5 were investigated in rats by the retrograde transport method. The pathways and functions of nerve fibers supplying the dorsal portion of the discs were investigated by denervation and immuno-histochemistry. ⋯ The dorsal portion of the lumbar discs from L1-L2 to L4-L5 is multisegmentally innervated by the T11 through L5 dorsal root ganglions. Sensory fibers from the upper dorsal root ganglions innervate the dorsal portion of the discs via the paravertebral sympathetic trunks, although those from the lower dorsal root ganglions innervate via the sinuvertebral nerves. Furthermore, sensory nerve fibers enter the paravertebral sympathetic trunks through the corresponding ramus communicans and reach the dorsal root ganglions via each ramus communicans at the L2 and/or more cranial levels.
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This study was designed to investigate, using neurophysiologic techniques in an in vivo rat model, the effect of application of nucleus pulposus to the nerve root on the neural activity of the dorsal root ganglion and the corresponding receptive fields. ⋯ After application of nucleus pulposus to the nerve root, the dorsal root ganglion demonstrated increased excitability and mechanical hypersensitivity. These results suggest that nucleus pulposus causes excitatory changes in the dorsal root ganglion.
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It is always gratifying to be acknowledged by a colleague and asked to give a talk in a faraway land about a topic of one's particular interest. To be invited, however, to give the Harry Farfan Presidential Lecture at the 27th Meeting of the International Society for the Study of the Lumbar Spine is, for me, a special honor and privilege. Too many years ago, when I was a very junior faculty member at the School of Physical and Occupational Therapy at McGill University in Montreal, Canada, we offered our students a course in Orthopedic Conditions. ⋯ Harry Farfan graciously agreed and provided several lectures for our students. He told them about the surgical management of problems of the lumbar spine and the necessity of treating the "whole" patient, as well as about his theory as to the cause of low back pain. At that point in time, we were not talking about quality of life as an outcome of care for our patients, but I cannot help but believe that he would keenly approve of the subject of this presentation.