The Utility of IR-Guided Biopsy in the Treatment of Pediatric Osteomyelitis

Background: Accurate and efficient diagnosis, as well as a consistent and effective treatment of acute hematogenous osteomyelitis, are paramount to ensure successful clinical outcomes. Noninvasive measures of isolating the causative pathogen from blood cultures have low sensitivity, with published rates often <50%. The use of interventional radiology (IR)-guided percutaneous biopsy has gained traction as a nonsurgical means of obtaining tissue cultures with a reported increased sensitivity of >90%. This study aims to determine the utility of IR-guided biopsy in the management of pediatric patients with acute hematogenous pediatric osteomyelitis (OM). Methods: An IRB-approved retrospective review was completed of children younger than 18 years admitted to a single institution for treatment of magnetic resonance imaging or culture/biopsy-proven acute hematogenous OM. Patients were excluded for the diagnosis of chronic recurrent multifocal OM, incomplete documentation, treatment initiation at an outside institution, open surgical debridement, and concomitant septic arthritis. Patients who underwent IR-guided biopsy were compared with those treated empirically without biopsy. Results: Fifty patients were included for analysis. Fifteen (30%) had IR-guided biopsies; 35 (70%) were treated empirically. The average age at diagnosis was 11.8 years old (SD: 4.9). Of the 15 patients who underwent IR-guided biopsy, a pathogen was identified in 12 cases (80%); 14 of these patients had concomitant blood cultures with only 1 (7%) positive result (P<0.01). Of the 11 patients with positive IR-guided biopsy results in the setting of negative blood cultures, 9 (82%) had alterations in their antibiotic regimen as a result of the biopsy. The average time from blood sample collection to definitive antibiotic initiation was nearly double that of time from IR-guided biopsy collection to definitive antibiotic initiation (70.8 vs. 36 h; P<0.01). Conclusion: IR-guided biopsy increased pathogen identification by 47% over blood cultures alone and decreased the time to definitive antibiotics. As such, IR-guided biopsy is an effective and safe diagnostic tool for pathogen identification and appropriate antibiotic selection. Orthopaedic surgeons are encouraged to incorporate IR-guided biopsy early in the treatment pathway for patients with acute OM without an indication for open surgical intervention. Level of Evidence: Level III; retrospective comparative study.