[Bacterial spondylodiskitis: pyogenic or tuberculous?]

We retrospectively studied the epidemiological, clinical, radiological and evolutive aspects of bacterial spondylodiskitis observed in 39 patients diagnosed from January 1989 to December 1998, in order to find criteria to distinguish between pyogenic spondylodiskitis (PS) and tuberculous spondylodiskitis (TS). During the study period, we collected 13 patients (33.3%) with PS and 26 patients (66.7%) with TS. The mean age was 44 years. The delay in diagnosis was much longer in TS (8.4 months) than in PS (2 months). Diagnosis was certain in 6 cases (46%) of PS and in 12 cases (46%) of TS. Clinically, paravertebral abscesses and neurologic complications were significantly more frequent in TS. The main causative agents in PS were staphylococci. Diagnosis of spondylodiskitis is based on the imaging techniques, especially magnetic resonance imaging which is more sensitive and specific than computed tomography. Except in patients with positive blood cultures or positive urine culture in PS, and isolation of Mycobacterium tuberculosis in another visceral foci in TS, bacteriologic diagnosis was based on discovertebral needle biopsy. The yield of this technique was poor in our study (12.5%), even if bacteriologic confirmation of spondylodiskitis was made in 15 patients (38.5%). In the other cases, diagnosis rested on a set of clinical, biological and radiological criteria.