Retrospective study on the osteoradionecrosis of our department

Sixty cases of osteoradionecrosis of the mandible were retrospectively studied. The primary sites of those were 37 tongue, 12 mouth floor, and 11 oropharynx. The majority of tongues were treated by combined 137Cs implant with 60Co external irradiation. Most mouth floors and all oropharynxes were irradiated by 60Co external irradiation. The average doses of irradiation were 89.5 Gy in the tongue, 61.1 Gy in the mouth floor, and 81.3 Gy in the oropharynx. The degree of disease in osteoradionecrosis was classified as follows, severe which had a skin fistula or a pathological fracture, mild which formed a sequester bone, slight which temporarily exposed bone. Of all cases, the most were severe and only one slight case. The mild cases of the tongue were as many as severe cases but the severe cases in both mouth floor and oropharynx were much more than the mild cases. The severe cases were mostly found in external irradiation and few in intestinal irradiation. It seems that the severity is related to the dose of external irradiation. There was the tendency for severe cases of the tongue with combined radiotherapy to be mostly found by dose more than 40 Gy of the external irradiation regardless of dose of intestinal irradiation. The severe and progressive cases were mostly recognized in external irradiated cases. (author)