Predictors of microbiological yield in image-guided biopsy for spondylodiscitis: impact of prior antibiotic exposure and biopsy timing.

PURPOSE: Several factors influence the microbiological yield of image-guided biopsy for spondylodiscitis, yet the impact of prior antibiotic exposure remains controversial. Evidence on the effect of antibiotic interruption duration is limited and inconsistent. Although the 2015 Infectious Diseases Society of America guidelines suggest withholding antibiotics before biopsy when feasible, supporting evidence remains insufficient. In this study, we aimed to identify the predictors of microbiological yield, focusing on prior antibiotic exposure and interruption duration.

METHODS

We retrospectively reviewed 53 patients who underwent fluoroscopy- or computed tomography-guided biopsy for spondylodiscitis. Clinical and procedural variables were evaluated for associations with microbiological yield. Among patients receiving antibiotics prior to biopsy, yield was compared according to interruption duration (0-3 vs. ≥ 4 days).

RESULTS

Positive cultures were obtained in 28/53 patients (52.8%). Paravertebral abscess independently predicted positive biopsy yield (odds ratio [OR], 6.80; 95% confidence interval [CI], 1.73-33.62; p = 0.010). Prior antibiotic exposure (60.7% vs. 52%, p = 0.586) and antibiotic interruption (0-3 vs. ≥ 4 days: 66.7% vs. 41.7%, p = 0.264) did not significantly affect yield.

CONCLUSION

Presence of a paravertebral abscess was associated with higher microbiological yield in image-guided biopsy for spondylodiscitis. Yield was not significantly influenced by prior antibiotic exposure or interruption duration, suggesting that strict antibiotic withholding may not be necessary before biopsy.