Examining the current image-guided biopsy and empiric antibiotic paradigm for suspected spondylodiscitis

This study aims to identify factors associated with successful pathogen isolation via percutaneous image-guided biopsy (IGB) in suspected spondylodiscitis, compare diagnostic value between fluoroscopy and computed tomography (CT) guided IGB, evaluate the influence of empiric antibiotics prior to biopsy, and assess the impact of IGB results on clinical management and patient outcomes.

This retrospective study examined 81 IGBs (62 CT-guided, 19 fluoroscopy-guided) performed for suspected spondylodiscitis between March 2014 and February 2025. Retrospective diagnosis was determined using a composite of biopsy microbiology, clinical criteria, and radiologic findings. Primary analyses included IGB culture yield (procedural diagnostic return), as well as sensitivity, specificity, and diagnostic accuracy. Subgroup analyses included biopsy modality and prior antibiotic administration.

The overall culture yield was 37.0%, with a sensitivity of 44.4% and a specificity of 88.9%. Culture yield did not differ significantly among patients who received antibiotics prior to biopsy (36.4%) and those who did not (37.8%; P = 0.890). Similarly, no significant difference in yield was observed between CT-guided (38.7%) and fluoroscopic IGB (31.6%; P = 0.586). No significant difference was observed between the coaxial devices used for either transpedicular bone biopsy (P = 0.604) or disc biopsy/aspiration (P = 1.000). Excluding tuberculosis (TB) case, 97% of cultured organisms were susceptible to the institution's standard empiric antibiotic regimen of vancomycin and ceftriaxone.

In cases of suspected spondylodiscitis, IGB demonstrated low sensitivity and rarely altered clinical management during the study. Culture yield was not significantly diminished by prior antibiotic therapy, and 97% of cultured organisms (excluding TB) were susceptible to this institution's standard empiric antibiotics. Furthermore, the relative infrequency of positive cultures suggests that empiric antibiotic initiation should not be delayed solely for the purpose of biopsy in clinically stable patients with characteristic magnetic resonance imaging findings and elevated inflammatory markers. Although the findings in this single-center retrospective study support consideration of a more selective use of IGB, further multicenter studies and meta-analyses are warranted.

If additional larger studies corroborate these findings, this could result in a paradigm shift for the clinical management of suspected spondylodiscitis.