A bicentric propensity score matching study comparing percutaneous computed tomography-guided radiofrequency Ablation to Magnetic Resonance-guided Focused Ultrasounds for the treatment of osteoid osteoma.

PURPOSE To assess safety and efficacy of CT-guided radio frequency ablation (RFA) and Magnetic Resonance guided Focused Ultrasounds (MRgFUS) in the treatment of osteoid osteoma with a long-term follow-up study (mean follow-up time longer than 2 years). MATERIALS AND METHODS Database research was carried out in two different centres with experience in musculoskeletal interventions. Both centres, one performing RFA, the other MRgFUS, identified 116 patients, who were submitted to either RFA or MRgFUS for the treatment of symptomatic osteoid osteoma and retrospectively evaluated data regarding pain scores (using a visual analogue scale). Complications were recorded according to the CIRSE classification system. Propensity score matching for multiple variables was performed. Pre- and post-therapy pain scores were compared. RESULTS Out of the 116 patients treated, 61 underwent RFA and 55 MRgFUS. The mean values of pre-treatment pain in the two groups were 9.1±0.88 (RFA) and 8.7±0.73 (MRgFUS) VAS units. Post- treatment statistically significant (p<0.00001) overall reduction in pain symptomatology was recorded. No statistically significant difference was observed between the post-treatment mean values of both groups (p=0.256). Four cases of relapse (1 RFA; 3 MRgFUS) and one complication (RFA) were observed. The analysis from propensity score matching that identified a matched cohort of 48 patients showed similar results. CONCLUSIONS Both techniques for the treatment of osteoid osteoma seem to ensure a similar pain relief. The presence of thick cortical bone over the nidus can of reduce the effectiveness of MRgFUS.