CT-guided radiofrequency ablation of osteoid osteoma in the long bones of the lower extremity

Abstract

Aim: To present our initial experience with computed tomography guided radiofrequency ablation (RFA) of osteoid osteoma (OO) in our institution.

Methods: RFA was performed on eight patients (5 males and 3 females) with clinically and radiologically diagnosed OO (femoral neck, n = 4; femoral diaphysis, n = 2; tibial diaphysis, n = 1; fibular diaphysis, n = 1). Ablation was performed using an electrode with a 10-mm exposed tip for a total of 4-6 min at a targeted temperature of 90 degrees Celsius. No cooling system was used. The intervention was accepted as technically successful if the tip of the electrode could be placed within the center of the nidus. We defined clinical success as a disappearance within 2 wk after treatment of symptoms that had manifested at presentation.

Results: All procedures were technically successful. No major or immediate complications were observed. Clinical success was achieved in six of eight patients in the first procedure. A second procedure was performed for two patients who had recurrent or continued pain, and one of these cases was successfully treated. The overall rate of success was 87.5% (7/8). No complication was observed.

Conclusion: Our preliminary results indicate a favorable success rate and no complications and are compatible with the previous reports of RFA of OO.

Keywords: Ablation; Computed tomography; Osteoid osteoma.

Figure 1

Case 5: radiofrequency ablation for a 14-mm-diameter osteoid osteoma of the left femoral neck. A: A computed tomography (CT) image shows the medullary nidus surrounded by sclerosis (arrow); B, C: Axial (B) and coronal (C) CT images show the 10-mm cool-tip electrode at the center of the nidus. Ablation was performed only once. 4 mo after the procedure, the patient returned to our hospital due to recurrent pain. A second ablation was successfully performed.

Figure 2

Case 4: radiofrequency ablation for an 11-mm diameter Osteoid osteoma of the diaphysis of the left femur. A: A computed tomography (CT) image shows an ovoid lucent lesion with central mineralization (arrow); B, C: The radiofrequency ablation needle was placed at multiple positions.