FRI0437 CT GUIDED NEEDLE BIOPSY IN VERTEBRAL OSTEOMYELITIS: RELIABILITY ANALYSIS AND STUDY OF WHICH FACTORS COULD INFLUENCE ON THE RESULT
Authors: J. J. Fragio-Gil, R. Gonzalez Mazario, E. Grau García, M. De la Rubia Navarro, C. Pávez Perales, S. Leal Rodriguez, J. Ivorra Cortés, L. Gonzalez Puig, R. Negueroles Albuixech, I. Martínez Cordellat, I. Chalmeta Verdejo, J. E. Oller Rodríguez, C. Alcañiz Escandell, E. Vicens Bernabeu, F. M. Ortiz Sanjuan, C. Nájera Herranz, I. Cánovas Olmos, A. J. Cañada Martinez, M. Salavert Lleti, J. A. Román Ivorra
Journal: Annals of the Rheumatic Diseases (2020)

Background: Vertebral Osteomyelitis is an infectious disease of the vertebral body, also termed spondylodiscitis if the intervertebral disc is involved (which its avascular). Since the bacteriological characterization is in many times difficult and blood cultures are often negative, a bone biopsy is in most of the cases encouraged. Objectives: The aim of this study is to analyze which factors could influence on the result of a CT guided biopsy (CTGB) in vertebral spondylodiscitis patients. Methods: A retrospective observational study was performed including patients diagnosed of spondylodiscitis in a single center who underwent a CTGB. Demographic features and comorbidities, acute phase markers, microbiological results, radiological data, antibiotic exposure, medical complications and the clinical outcomes were also collected for analysis. Standard procedure in our center is performed by Musculoskeletal Specialized Radiologist under local anesthesia and CT control. Abscess sample is collected with a 18G needle with coaxial technique, trying to obtain at least 3 samples. For discal space, a thicker needle (13.5G-15G) is used. A logistic regression including cofounding factors was performed using R software. Results: A total of 86 were included with a mean age of 62.75 (14.98) years old and predominationg male sex (68.60%). 15 patients (17.44%) presented any kind of immunosuppression. Clinical data are summarized in Table 1. Blood cultures were positive in 39.71% and sample culture showed a reliability of 49%. Organism which grew were gram + (66.67%), gram – (12.70%), mycobacteria (12.7%) and fungi (7.94%). In only 16 cases (18.6%) there was isolated the same organism in blood and on biopsy culture. From admission to procedure, a mean of 6 days was observed. Antibiotic treatment had a median value of 2 days (0, 6) and its exposure did not modified the culture positivity (IC 95% [0.274-5.211] p=0.816). Detailed analysis was performed looking for the influence of the days of exposure, which also failed (IC 95% [0.939-1.101] p=0.747). The longer duration of the pain was related to a higher probability of obtaining a negative result on the biopsy (IC 95% [1.004-1.035] p=0.026) (graphic 1). Neither fever (p=0.303) or higher CRP (IC 95% [0.992-1.006] p=0.761) value modified the culture result. Table 1. Demographic and clinical characteristics. N=86 % Clinical history High blood pressure 42 48.84 Diabetes Mellitus 19 22.09 Liver cirrhosis 16 18.60 Chronic kidney failure 13 15.12 Active Systemic Malignancy* 2 2.33 Rheumatoid arthritis* 3 3.49 Spondyloarthritis* 1 1.16 HIV infection* 4 4.65 Solid organ transplant receptor* 3 3.49% Systemic Amyloidosis* 1 1.16 Splenectomy* 2 2.33 Previous spine pathology 50 58.14 Underlying/associated endocarditis 2 2.33% *Considered as immunosuppressed patients Conclusion: Even in cases under antibiotic treatment, CTGB displays an acceptable reliability. The longer the length of painful period before diagnosis was related to a higher chance of obtaining a negative result on culture. This result could be explained by a greater aggressiveness of pyogenic organisms that perhaps congregate in the lesser time span instead of non-pyogenic agents, that could deliver in more silent infection. References: [1]IDSA Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults Disclosure of Interests: None declared