• Age ≥5 years
• Subject able to give informed consent or subject assents with informed consent from parent or guardian
• Weight <140 kg (requirement to fit safely on top of the MRgFUS table and inside the MR magnet)
• Definitive radiographic and clinical presentation of an osteoid osteoma
o OR biopsy proven osteoid osteoma when clinical or imaging findings are inconclusive
• Pain specifically at the site of interest (target lesion)
• Pain intensity (for the target lesion) in the moderate to severe range as measured by age-appropriate validated pain assessment tools.
• Target lesion is uncomplicated (no fracture/spinal cord compression/cauda equina syndrome/soft tissue component)
• Target lesion maximum dimension ≤3 cm (otherwise lesion may not be an OO)
• Target lesion visible by noncontrast MRI
• Target lesion accessible for MRgFUS procedure
• MRgFUS treatment date ≥2 weeks from most recent surgical/radiologic treatment of osteoid osteoma
• Unable to characterize pain specifically at the site of interest (target lesion)
• Pregnant female
• Target lesion is complicated (presence of one of fracture/soft tissue component).
• Target lesion <1 cm away from the skin, neurovascular bundles, bowel, hollow viscera, or regions of cartilage/ bone growth plate
• Target lesion located in the skull and spine (excluding sacrum)
• Inability to position area of interest on the MRgFUS transducer
• Scar along proposed MRgFUS beam path or unable to exclude scar from path
• Orthopedic implant along proposed MRgFUS beam path or at site of target lesion
• Serious cardiovascular, neurological, renal, or hematological chronic disease
• Active infection
• Contraindication to deep sedation/general anesthesia or MRI
• Contraindication to gadolinium (nursing mothers, renal failure, etc.) is a relative contraindication to the procedure. MRgFUS can still be performed but perfusion information would not be obtained.