699Long Term Outcome of Pyogenic Vertebral Osteomyelitis: A Cohort Study of 260 Patients

BACKGROUND The long-term outcome of patients with pyogenic vertebral osteomyelitis (PVO) has not been fully assessed. METHODS We conducted a retrospective cohort study to describe the long-term outcome of PVO and to assess risk factors for treatment failure in patients evaluated at our institution between 1994 and 2002. Patients were observed until July 1, 2013. RESULTS Two hundred sixty patients with PVO were included in this study. Twenty-seven percent (70) of patients developed their infection after an invasive spinal procedure. Staphylococcus aureus accounted for 40% (103) of infections. Forty-nine percent (128) of patients underwent spinal surgery as part of their initial therapy. The median duration of parenteral antimicrobial therapy was 42 days (interquartile range, 38-53). The estimated 2-, 5-, and 10-year cumulative probability of treatment failure-free survival was 72%, 69%, and 69%, respectively. Seventy-five percent of patients who developed treatment failure did so within 4.7 months of diagnosis. Residual neurological defects and persistent back pain were seen in 16% and 32% of patients, respectively. In a multivariate analysis, longer duration of symptoms before diagnosis and having an infection with S. aureus were associated with increased risk of treatment failure. CONCLUSIONS Increasing duration of symptoms and infection with S. aureus were associated with treatment failure in patients with PVO. Most treatment failures occurred early after initiation of treatment. Pyogenic vertebral osteomyelitis is associated with a high 2-year failure rate. Persistent neurological deficits and back pain are common after therapy.