SEPTIC AND ASEPTIC POSTOPERATIVE DISCITIS IN THE LUMBAR SPINE - EVALUATION BY MR-IMAGING

Purpose: The aim of this study was to determine whether it was possibl e to differentiate septic from aseptic post-operative discitis in the lumbar spine by means of MR imaging. Material and Methods: The study w as a retrospective evaluation of 12 patients with prior lumbar discect omy and suspected post-operative discitis displaying low-back pain and typical MR findings. Six patients had elevated serum C-reactive prote in (CRP) (septic) and 6 had normal CRP (aseptic). We used MR imaging t o assess the distribution and degree of changes in the disc, in adjace nt bone marrow, and in surrounding soft tissue. Results: Of the 6 pati ents with increased CRP levels, 3 had extensive MR changes typical of septic post-operative discitis: 1 found soon after surgery; 2 found la ter. The other 3 patients with septic discitis, who were examined in t he early post-operative period, showed MR changes similar to those in the 6 patients with aseptic discitis. Conclusion: Suspicion of septic post-operative discitis should be confirmed by MR imaging, serum CRP, and disc puncture. MR imaging is not reliable as the sole method for d istinguishing septic from aseptic discitis in the early postoperative stage.