Radiation therapy for heterotopic ossification in a patient with traumaticbrain injury

Radiation therapy has been known to have a prophylactic effect for heteroto pic ossification (HO), but until now it has not been known to have a therap eutic effect for established HO. We report a case of established HO compoun ded with a sudden increase in activity, that was improved with radiation th erapy. A patient with traumatic brain injury had HO in both hips and thighs two months after the initial trauma. The existing level of HO activity sud denly increased seven months after the initial trauma, and was accompanied by severe pain that was refractory to indomethacin. We assumed chat the pai n was caused by the increased activity of HO on the basis of clinical sympt oms and laboratory results. Initially, che patient received radiation thera py to the left lower extremity, with a total dose of 20 Gy in ten tractions . Next, the patient received radiation therapy at the same dosage to the ri ght lower extremity, after which the pain and level of serum alkaline phosp hatase significantly decreased. The patient experienced a mild pancytopenia as a side effect of the radiation therapy, but it was not severe enough to stop the radiation therapy, given the patient's suffering from the increas ed HO activity.