1426. Outcomes of Additional Instrumentation in Elderly Patients with Pyogenic Vertebral Osteomyelitis and Previous Spinal Instrumentation

BACKGROUND: In patients with pyogenic vertebral osteomyelitis (PVO) and previous instrumentation requiring surgical treatment, a decision must be made between a less invasive non-instrumented surgery, including retaining the previous instrumentation, or a more invasive additional instrumented surgery involving the complete removal of the infected tissue and firm re-stabilization. METHODS: A retrospective cohort study (case–control study) was planned to evaluate the clinical outcomes of using additional instrumentation in patients with PVO and previous instrumentation. Patients were divided into two groups (instrumented or non-instrumented) according to the presence or absence of additional instrumentation. The baseline characteristics, infection profile, and treatment outcomes were compared between the two groups, and a multivariate logistic regression analysis was performed to identify the risk factors for infection recurrence. RESULTS: A total of 187 postoperative patients with PVO and previous spinal instrumentation were included. There were no significant differences in the baseline characteristics except the presence of a titanium cage. Surgery for additional instrumentation in patients with PVO and previous instrumentation showed similar rates of infection recurrence and mortality compared with non-instrumented surgery despite a larger number of involved vertebral levels and greater incidence of epidural abscesses (Table 1). However, instrumented patients with PVO and previous instrumentation who experienced infection recurrence had worse clinical outcomes than those of the non-instrumented patients with PVO (Table 2). Severe medical comorbidities, the presence of a psoas abscess (Figures 1 and 2), and methicillin-resistant Staphylococcus aureus infection were associated with a higher risk of infection recurrence. CONCLUSION: Surgery for additional instrumentation in patients with PVO and previous instrumentation showed similar rates of infection recurrence and mortality to those who underwent non-instrumented surgery despite a larger number of involved vertebral levels and an increased frequency of epidural abscesses. [Image: see text] [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.