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Inflammatory mechanisms have been suggested to be involved in the basic pathophysiologic events leading to nerve root injury after local application of nucleus pulposus. To assess if these nucleus pulposus-induced effects could be blocked by anti-inflammatory treatment, 41 dogs were exposed to either incision of the L6-7 disc to induce experimental disc herniation with (n=12) or without (n=14) indomethacin treatment per os (5 mg/kg per day), and no incision with (n=5) or without (n=10) indomethacin. Intraneural blood flow and nerve conduction velocity were assessed after 7 days to evaluate the degree of nerve injury. Disc incision induced a reduction in nerve root and dorsal ganglion blood flow as well as nerve function, similarly to previous studies. However, simultaneous treatment with indomethacin efficiently blocked the negative effects on both blood flow and nerve conduction but had no effects per se. The present study thus indicates that inflammatory mechanisms may be of relevance in the pathophysiology of nucleus pulposus-induced nerve root injury and thereby also for sciatica. [ABSTRACT FROM AUTHOR]

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A rodent model has been developed to explore intramedullary osseointegration and the phenomena of osseoperception. Osseointegration with endosseous titanium implants is frequently used in oral surgery. More recently, intramedullary osseointegration has been used for direct skeletal anchoring of amputation prostheses, a procedure that provides for a stable prosthesis with improved perception. Experimental, commercially pure titanium rods with threaded ends were surgically implanted in the intramedullary space of 18 rat femurs, and were left in place for 8 wk. Microscopic and immunohistochemical observation of the titanium/bone interface at this time-point indicated successful osseointegration with normal remodeled bone adjacent to the fixture. Calcitonin gene-related peptide activity was upregulated during the process of bone remodeling, and there was no significant inflammatory reaction. There was new, normal bone adjacent to and fully occupying the space between fixture threads. Innervation also appeared normal in remodeled bone, as indicated by immunohistochemical observation of small nerve fibers with the antibody Protein Gene Product 9.5 (PGP 9.5). The model will be used further to explore intramedullary osseointegration and osseoperception in connection to clinical applications. [ABSTRACT FROM AUTHOR]