Clinical features and outcome of vertebral osteomyelitis after spinal injection: is it worth the price?

PURPOSE

Spinal injections are increasingly used for back pain treatment. Vertebral osteomyelitis (VO) after spinal injection (SIVO) is rare, but patient characteristics and outcome have not been well characterized. The aim of this study was to assess patient characteristics of SIVO in comparison to patients with native vertebral osteomyelitis (NVO) and to determine predictors for 1-year survival.

METHODS

This is a single-center cohort study from a tertiary referral hospital. This is a retrospective analysis of Patients with VO who were prospectively enrolled into a spine registry from 2008 to 2019. Student's t-test, Kruskal-Wallis test or Chi-square test were applied for group comparisons. Survival analysis was performed using a log-rank test and a multivariable Cox regression model.

RESULTS

283 VO patients were enrolled in the study, of whom 44 (15.5%) had SIVO and 239 (84.5%) NVO. Patients with SIVO were significantly younger, had a lower Charlson comorbidity index and a shorter hospital stay compared to NVO. They also showed a higher rate of psoas abscesses and spinal empyema (38.6% [SIVO] vs. 20.9% [NVO]). Staphylococcus aureus (27%) and coagulase-negative staphylococci (CNS) (25%) were equally often detected in SIVO while S. aureus was more frequently than CNS in NVO (38.1% vs. 7.9%).Patients with SIVO (P = 0.04) had a higher 1-year survival rate (Fig. 1). After multivariate analysis, ASA score was associated with a lower 1-year survival in VO.

CONCLUSION

The results from this study emphasize unique clinical features of SIVO, which warrant that SIVO should be estimated as a separate entity of VO.