Diptheroids and associated infections as a cause of failed instrument stabilization procedures in the lumbar spine.

Between February 1985 and October 1987, the authors identified seven patients with occult lumbar spine infections associated with the presence of spinal fixation hardware. Six of these infections were with organisms of low virulence; four of the seven patients had polymicrobial infections. All of the polymicrobial infections contained a Diptheroid as one of the isolates. Two of the seven patients studied had normal sedimentation rates. All had white blood cell counts less than 12,000 cells. Imaging studies were not helpful with the exception of one case with a positive gallium scan. The diagnoses were supported by clinical presentation, pathologic tissue changes, positive cultures, and response to therapy. Successful therapy was obtained by removal of hardware and treatment with antibiotics.