Target-specific yield rate and clinical utility of percutaneous tissue sampling in spinal infection

Percutaneous tissue sampling in spondylodiscitis is frequently performed but with highly variable yield in literature and unclear clinical impact. Factors that influence the culture success rate are not well established.

To determine target specific yield and clinical impact of percutaneous biopsy in clinically and imaging diagnosed spinal infection and factors that may influence the yield rate.

Institutional review board approved single center retrospective chart review from 2015 to 2019 analyzing imaging findings, clinical notes, procedural reports, and laboratory results on cases of concurrent imaging and clinically diagnosed spondylodiscitis that underwent percutaneous tissue sampling.

A total of 111 patients and 189 specimens were analyzed. The overall culture yield in spondylodiscitis was approximately 27%, 9% affecting management. Abscess/fluid and septic arthritis aspirations had higher yield rates compared to soft tissue/phlegmon aspirations. Core sampling of the bone and disc yielded positive culture 12% of the time, 2% resulted in change in management. Upper thoracic spine biopsies were more frequently positive and associated with change in management. Positive culture elsewhere in the body represented the major reason underlying lack of clinical impact. Lack of prior antibiotic treatment and diabetes mellitus demonstrated a trend toward higher culture positivity, although a larger sample size is needed to confirm these findings. No repeat biopsy yielded positive culture. Staphylococcus spp. accounted for approximately half of the microorganisms cultured. In positive biopsies where infection was also found elsewhere in the body, the organism was nearly always congruent (96%).