Histopathologic effects of discitis on neural tissues: an experimental study.

To determine the cause of neurologic symptoms and signs seen in discitis, the neural histopathologic effects of discitis were investigated in an experimental study carried out on rats. Groups of seven rats each had their intervertebral discs inoculated with either Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, or a control solution. Histopathologic examinations of the spinal cord and nerve roots were performed after 3 weeks. On histopathologic examination, vacuolar myelopathy in the spinal cord and vacuolar neuropathy within the nerve roots near the junction with the spinal cord were found. The severity and form of vacuolar myelopathy varied according to the bacteria used for inoculation. The myelopathy and neuropathy seen in this rat model of bacterial discitis might be the result of an immunologic mechanism and could be responsible for the neurologic signs and symptoms of discitis in patients.