MRgFUS treatment of superficial osteoid osteomas of the lower limbs

Background/introduction Osteoid osteoma (OO) is a relatively common benign bone tumor (2-3% of all bone tumors, 10% of benign bone tumors) usually developing in children and young adults. It is quite painful and patients typically complain of localized pain that is worse at night and characteristically relieved by non-steroid anti-inflammatory drugs (NSAIDs). Conventional treatment options include surgery, systemic drugs administration, and imaging guided percutaneous procedures. Minimally invasive procedures are considered of primary importance, and this is even enhanced considering the benign nature of the lesion and the young age of the affected population. CT guided radiofrequency ablation (CTgRFA) is the most popular percutaneous technique with clinical success rate reported between 85% and 98%. However, CTgRFA is still rather invasive, and it requires CT-guidance, with obvious concerns linked to radiosensitivity especially of young patients. MR guided focused ultrasound surgery (MRgFUS) is a minimally invasive procedure that can be performed relatively fast, in a single session and with limited amount of energy deposition and no use of ionizing radiation.