Purpose or Case Report: Bone biopsy for histopathology and tissue culture remains the gold standard for diagnosis of osteomyelitis. However, MRI often results in a radiologic diagnosis of osteomyelitis preceding biopsy. The purpose of this study is to examine the diagnostic yield of percutaneous bone biopsies and the effect of biopsy results on clinical management in children with suspected osteomyelitis and positive MRI findings.
Methods & Materials: An IRB-approved retrospective review was performed at a tertiary care children’s hospital. A search of the electronic medical record and radiology PACS identified patients less than 18 years of age who underwent percutaneous bone biopsy in the interventional radiology department for a primary indication of osteomyelitis and had positive MRI findings for osteomyelitis prior to biopsy. Data was collected on patient demographics, MRI findings, biopsy procedural details, tissue culture and histopathology results, and clinical management before and after biopsy. Changes in management were categorized as antibiotic type/quantity, duration, or diagnosis.
Results: A total of 82 bone biopsies in 79 patients with clinical suspicion for osteomyelitis and positive MRIs prior to biopsy were performed over a 5-year period from October 2014 to September 2019. All biopsies were successful, sent for tissue culture, and without associated complications. 22/82 biopsies (27%) yielded positive tissue cultures. Of those with positive tissue cultures, 16/22 (72%) resulted in a change in clinical management. Of all biopsies, 18/82 (22%) resulted in a change in clinical management (15 antibiotic, 1 duration, 2 diagnosis). In the two cases which had changes in management but negative tissue cultures, one had narrowing of antibiotics based on the negative culture result and the other was initiated on empiric antibiotics based on the histologic diagnosis of osteomyelitis.
Conclusions: In the pediatric population, percutaneous bone biopsy is a safe procedure with a high success rate. However, there is a relatively low rate of positive tissue cultures even with MRI findings suspicious for osteomyelitis (though rates are similar to those reported in adults). Approximately 1 in 5 biopsies resulted in a change in clinical management, mostly changes in antibiotic selection. Bone biopsy may have a higher clinical impact in certain circumstances, such as poor response to standard therapy, patients at risk for atypical infections, or inconclusive clinical/imaging findings.