Radiofrequency ablation under 3D intraoperative Iso-C C- arm navigation for the treatment of osteoid osteomas

Objective: To evaluate the efficacy of intraoperative three-dimensional (3D) Iso-C C-arm- navigated percutaneous radiofrequency ablation (RFA) of osteoid osteomas.Methods: 35 patients (20 males and 15 females) with osteoid osteomas underwent treatment with intraoperative 3D Iso-C C-arm navigation-guided RFA. The tumour was first biopsied for pathological examination, the core needle was removed and the RFA needle was inserted into the nidus. Post-operative X-rays and CT scans were performed to evaluate the degree of ablation and to assess for recurrence at 3-month follow-up. Patients also completed a visual analogue scale (VAS) both pre-operatively and 3 days post-operatively to subjectively assess pain.Results: Pathological diagnosis confirmed osteoid osteoma in 19 cases. The other 16 cases were not pathologicallydiagnosed owing to inadequate biopsy specimens. In all cases, localized pain was immediately relieved following RFA. Patients reported significantly decreased pain, with mean pre- operative VAS scores of 3.4 reducing to 0.80 at 3 days post-operatively and further to 0.06 at 3-month follow-up (p ,0.05). The mean follow-up time was 15.5 months (range: 3–38 months).Conclusion: 3D Iso-C C-arm navigation-guided RFA is a safe and effective option for the treatment of osteoid osteomas and may be considered in place of intra-operative CT-guided and open resection.Advances in knowledge: C-arm image-guided percutaneous RFA mitigates the need for pre- operative CT as well as intraoperative scintigraphy, provides real-time imaging of the anatomy, facilitates accurate resection of the tumour and enables immediate confirmation of excision.