Management Outcomes after Image-Guided Percutaneous Biopsy for Suspected Vertebral Osteomyelitis-Discitis

BACKGROUND AND PURPOSE: Studies show a modest yield for image-guided biopsy of suspected vertebral osteomyelitis-discitis. Many studies evaluate factors to improve diagnostic yield, and few studies assess how biopsy results impact clinical management. We aim to evaluate the impact of biopsy results on clinical management in suspected vertebral osteomyelitis-discitis.

MATERIALS AND METHODS: We performed a retrospective study of patients who underwent image-guided biopsy for suspected vertebral osteomyelitis-discitis. Data collected included risk factors, imaging findings, laboratory values, antibiotics, biopsy procedure details, microbiology and pathology results, and clinical course. Factors assessed for management change included whether biopsy results affected antibiotic type or course, decision to start or stop antibiotics, surgical decisions, or if an alternate diagnosis was determined.

RESULTS: Three hundred ten biopsies were included. Biopsy yield with true-positive culture results was 34% (104/310) and similar for patients on antibiotics (36%, 34/94) and off antibiotics (32%, 66/204). Yield was greater when disc was sampled (36%, 82/228) versus bone only (8%, 2/24) and with aspiration of disc and/or bone (42%, 39/92) versus core only (29%, 56/193). With positive blood cultures before biopsy, biopsy yield was 50% (22/44) with concordance and discordance rates of 75% (18/24) and 17% (4/24), respectively, and 8% (2/24) of positive biopsy results deemed contaminants. Management was affected in 36% (113/310) of all biopsies and in 78% (81/104) of biopsies with a positive culture result. No management change occurred in 57% (177/310) of biopsies. Management change was unclear in 6% (20/310). Biopsy results changed antibiotics in 27% (85/310). Management change occurred in 23% (10/44) of cases with prior positive blood culture compared with 41% (93/233) without a prior culture source (P = .024). Negative culture results influenced management in 16% (32/194).

CONCLUSIONS: Image-guided biopsy for vertebral osteomyelitis-discitis has a meaningful impact on management despite modest yield. Greatest management impact is seen with positive culture results, no prior culture source, and patients not on antibiotics at the time of biopsy. Biopsy culture yield is not affected by preceding antibiotics, and yield is greater with disc sampling and aspiration.