Spinal epidural abscess: aetiology, predisponent factors and clinical outcomes in a 4-year prospective study.

Spinal epidural abscess (SEA) is a rare, but serious, condition with multiple causes. We prospectively studied the aetiology, predisposing factors, and clinical outcomes of SEA in all patients with SEA treated in our hospital's neurosurgical service from 2004 to 2008. For each patient, we recorded the medical history, comorbidities, focus of infection, pathogen(s), and outcome. The 36 patients (19 women and 17 men) ranged in age from 34 to 80 years old (mean 57; median 56). The SEA was primary (i.e., due to haematogenous spread) in 16 patients (44%); it was secondary to elective spinal procedures, either injections or surgery, in 20 patients (56%). The duration of follow-up was 12-60 months (mean 36; median 37.5). The most common pathogen, Staphylococcus aureus, was found in 18 patients (50%). Patients with primary SEA had different underlying diseases and a wider range of pathogens than those with secondary SEA. Only five patients (14%) had no major comorbidity; 16 of the 20 patients with secondary SEA (44% of the overall group) had undergone spinal surgery before developing the SEA; the treatment of the SEA involved multiple surgical operations in all 16 of these patients, and spinal instrumentation in 5 (14%); 22 patients (61% of the overall group) recovered fully.