Image-guided percutaneous bone biopsy for pediatric osteomyelitis: correlating MRI findings, tissue pathology and culture, and effect on clinical management.

Bone biopsy remains the gold standard for diagnosis of osteomyelitis while MRI results in a radiologic diagnosis that generally precedes biopsy. This study's purpose is to examine the diagnostic yield and effect of biopsy results on clinical management in children with suspected osteomyelitis and positive MRI findings. A retrospective review was performed at a tertiary care children's hospital. Search of the EMR and radiology PACS identified patients below 18 years who underwent bone biopsy with interventional radiology for osteomyelitis and had positive MRI findings for osteomyelitis prior to biopsy. Data was collected on patient demographics, MRI findings, biopsy procedural details, tissue culture, histopathology results, and clinical management before and after biopsy. Changes in management were categorized as antibiotic type/quantity, duration, or diagnosis. A total of 82 biopsies in 79 patients with suspicion for osteomyelitis and positive MRIs prior to biopsy were performed over 5 years from 2014 to 2019. All biopsies were successful and sent for tissue culture. 22/82 biopsies (27%) yielded positive cultures. Of those with tissue cultures, 16/22 (72%) resulted in change in clinical management. Of all biopsies, 18/82 (22%) resulted in a change in management (15 antibiotic, 1 duration, 2 diagnosis). The 2 changes in diagnosis included one biopsy done which was positive for cancer and a second which was found to not demonstrate osteomyelitis on histology. In the pediatric population, bone biopsy is a reasonably low morbidity procedure. However, there is a relatively low rate of positive tissue cultures even with MRI findings suspicious for osteomyelitis. Approximately 1 in 5 biopsies resulted in a change in clinical management, mostly in antibiotic selection. Bone biopsy may have a higher clinical impact in pre-specified circumstances.