Characteristics and predictors of outcome of spontaneous spinal epidural abscesses treated conservatively: A retrospective cohort study in a referral center.

OBJECTIVE: Recent studies have shown that in carefully selected patients, conservative treatment alone can be an option in the management of spinal epidural abscess (SEA). The aim of this study was to identify prognostic factors of outcome in patients with spontaneous SEA treated conservatively.

PATIENTS AND METHODS: A retrospective cohort study of all patients with spontaneous SEA treated with antibiotics alone from January 2012 to December 2015 was conducted in a 1200-bed tertiary referral center. Demographic, clinical, microbiological, and radiological characteristics were analyzed. Failure of medical treatment was defined as the need for delayed surgical intervention, no neurological improvement or deterioration, death due to the infection, or relapse after hospital discharge.

RESULTS: We identified 21 patients diagnosed with spontaneous SEA treated conservatively. Median age was 72 years and 10 patients were male. Eleven patients presented with radicular weakness and/or radicular sensory deficit, or incomplete cord injury. Inflammatory markers were markedly elevated in all patients. Thirteen patients were successfully treated with conservative treatment, while among 8 patients with treatment failure, 1 died due to the infection. Presence of serious neurological deficits and infection due to methicillin-resistant S. aureus (MRSA) were associated with failure of conservative treatment. Notably, neither the extension nor the location of the abscess on magnetic resonance imaging (MRI) was associated with failed medical management.

CONCLUSIONS: A significant proportion of patients with spontaneous SEA can respond to antibiotic treatment alone. However, in patients with infection due to MRSA or with severe neurological impairment, conservative management has an increased risk of failure.