Osteoradionecrosis of the craniotomy flap: a rare complication of stereotactic radiosurgery.

Osteoradionecrosis (ORN), ischemic necrosis of irradiated bone without evidence of persisting or recurrent tumor, is a known complication of radiation therapy. ORN of the skull has not been reported following stereotactic radiosurgery (SRS). We report two cases of ORN of the skull following SRS for recurrent meningiomas post-resection. Both patients developed ORN in their craniotomy flaps in areas that received high doses of radiation due to their proximity to the recurrent tumors. In each case, the ORN was asymptomatic and was detected on surveillance magnetic resonance imaging. Both patients were followed closely with imaging that ultimately revealed either stability or improvement in the ORN, confirming the diagnosis without the need for biopsy. The cases reveal a role for close imaging surveillance instead of immediate biopsy in patients with new enhancement involving bone in high-dose radiation treatment regions.