Diagnostic yield of repeat CT-guided biopsy for suspected infectious spondylodiscitis.

OBJECTIVE: The purpose of this study was to examine the yield of repeat CT-guided biopsy in patients with suspected infectious spondylodiscitis following an initial biopsy with negative microbiology, and to identify factors associated with successful pathogen isolation. MATERIALS AND METHODS: In this retrospective study, 21 patients (12 men, 9 women; mean age, 52, range, 12-84) were identified with clinically and radiologically suspected infectious spondylodiscitis who underwent repeat biopsy following negative cultures from an initial biopsy. The microbe yield as well as demographic, clinical, and laboratory findings were reviewed and statistical analysis was performed. RESULTS: Repeat CT-guided biopsy isolated a causative microbe in 3/21 patients (14.3%). Younger age (p = 0.021) was significantly associated with successful microbe isolation. All three cases of successful microbe isolation occurred in patients not exposed to antibiotics (3/9 patients) whereas no successful microbe isolation occurred in patients who received antibiotics (0/12 patients); however, this difference did not reach statistical significance (p = 0.062). Gender, duration of symptoms, white blood cell count, biopsy interval, and biopsy site were not significantly associated with microbe isolation. CONCLUSIONS: Overall microbiologic yield of repeat CT-guided biopsy for patients with suspected infectious spondylodiscitis was low at 14.3%; however, a higher yield was identified in patients who were younger in age and not exposed to pre-biopsy antibiotics.