Methods: We performed a retrospective evaluation of adults with vertebral infections at our institution during 2003-13. Patients were excluded if they had incomplete medical records. The following information was obtained: underlying diagnosis, demographics, Charlson Weighted Index of Comorbidity (CWIC), receipt of prior antibiotics within 72 hours of biopsy, and microbiology (blood, percutaneous and open biopsy culture results). Patients with biopsies were compared by whether or not they received pre-biopsy antibiotics using Chi square and a p<0.05 was considered statistically significant.
Results: A total of 144 patients met inclusion criteria, their mean age was 59.6 +/- 11.2 years and 64.6% (93/144) were male. The mean CWIC was 2.2 +/- 2.2. Patients had the following diagnoses: 124 (86.1%) vertebral osteomyelitis, 92 (63.9%) diskitis and 27 (18.8%) epidural abscess (patients may have more than one diagnosis). Among 138 with blood cultures performed, 90 (62.5%) were positive for pathogens. There were 57 patients who had percutaneous biopsies and 29 (50.9%) were positive. Among 56 with available data, there was no difference in the frequency of positive cultures whether or not the patients had received prior antibiotics (13/26 no antibiotics vs. 15/30, p=1.0). Open biopsies were performed on 51 (35.4%) and 31 (60.8%) were positive. Among 50 with available data, there was also no difference in the frequency of positive cultures based on receipt of prior antibiotics (7/10 no antibiotics vs. 24/40, p=0.56). In patients with prior antibiotics and positive microbiology from biopsies, 85.2% were effective antibiotics. There were 11 patients with both percutaneous and open biopsy including 8 with negative percutaneous cultures.
Conclusion: In patients with biopsies for vertebral infections, there was no effect of recent antibiotics on the yield of cultures. Larger studies should be performed to confirm this finding.
J. Fishbain, None
S. Szpunar, None
L. B. Johnson, None