[Percutaneous radiofrequency ablation of osteoid osteoma: results from 9 years of experience in a third-level center.]

Introduction: Osteoid osteoma is a benign bone tumor that accounts for roughly 2-3% of primary bone tumors and up to 10-12% of benigns bone neoplasms. It is most commonly seen in young adults, and shows male predominance. Over the last years, minimally invasive thermal ablation techniques such as radiofrequency ablation have gained popularity over classical surgery. In this study we evaluate results and complications of CT guided osteoid osteoma radiofrequency ablation.

Materials and methods: In this retrospective cohort study all patients that were diagnosed with osteoid osteoma and treated using radiofrequency ablation between January 2014 and December 2022 were included. Pain was assessed using Visual Analog Scale (VAS) pre and post procedure. Technical success was established as positioning of the radiofrequency electrode in the nidus. Primary clinical success was defined as absence of pain after one radiofrequency session. All patients that required a second radiofrequency ablation were included in the overall clinical success group.

Results: During the studied period, 61 osteoid osteoma radiofrequency ablations were performed. Fiftyseven of them were included in this study, 32 were men and 25 female. Pre procedure median pain was 9 according to VAS score. Only 23 patients were treated as outpatient, the rest stayed in hospital for 24 hours. Median follow up time was 21,7 months (SD 8,3). Biopsy was performed in 52 patients. Technical success was accomplished in 57 patients (100%). Primary clinical success was 80,7% (46 patients). Those who continued with pain or had recurrence after a symptoms free period (11 patients), were treated with a second radiofrequency ablation, achieving an overall success rate of 94,7%. Only one patient suffered a minor complication (1,7%).

Conclusion: CT guided osteoid osteoma radiofrequency ablation is a safe, effective and low complication rate procedure, that can be performed on an outpatient basis. We believe it should be considered as a first line treatment option for osteoid osteoma.