Comparative study of postoperative and spontaneous pyogenic spondylodiscitis

Postoperative spondylodiscitis (POS) is poorly characterized, partly owing to its rarity. The aim of this prospective study was to compare the clinical, biological, bacteriological, and imaging features of postoperative and spontaneous spondylodiscitis (SS).

A multidisciplinary spondylodiscitis cohort follow-up study was conducted between February 1999 and June 2003 in a 500-bed teaching hospital. All patients hospitalized in internal medicine, orthopedic, and neurosurgery wards with a culture-proven diagnosis of pyogenic spondylodiscitis were included. Clinical and bacteriological data were collected. All patients underwent computed tomography and/or magnetic resonance imaging of the spine.

Sixteen patients had SS and 7 patients had POS. Patients with POS tended to be younger (52 versus 69 years), with less frequent underlying diseases (29 versus 75%) and a more prolonged interval between symptom onset and diagnosis (16 versus 3.4 weeks) than patients with SS. Blood cultures were positive in 14 and 81% of cases in the POS and SS groups, respectively, and invasive diagnostic procedures were necessary in 86% of patients with POS and 19% of patients with SS ( P = 0.005). Staphylococci were the more frequent isolates in both groups but were more frequently coagulase-negative in POS patients than in patients with SS ( P = 0.01). Vertebral edema tended to be more frequent in POS and was located more posteriorly than in SS ( P = 0.023).

POS is associated with specific clinical, microbiological, and imaging features possibly related to pathophysiologic characteristics. Knowledge of these characteristics should help reduce the current delay in the diagnosis of POS.