Osteoradionecrosis induced or exacerbated by dental infection. Report of a case

Osteoradionecrosis is one of the most serious complications after radiotherapy for head and neck neoplasms. Total radiation dose, dental status and anatomic location of tumors have been recognized as risk factors for the occurrence of osteoradionecrosis. Recently, some papers stressed the importance of pre- and postradiation oral care that might be effective in preventing and/or alleviating radiation complications. In this paper, We reported a case of osteoradionecrosis of mandible supposed to be induced and exacerbated by poor oral hygiene and dental infection. A 61-year-old male with an oral cancer (squamous cell carcinoma, T4NOMO) was treated with external irradiation (6MeV lineac total 56Gy) and interstitial irradiation (198Au grain from 60 Gy to 70Gy). Oral care started two years after the termination of radiotherapy but, oral hygiene had maintained inadequately for various reasons. At ten months thereafter, osteoradiomyelitis occurred in the molar region of the left mandible. It was treated with antibiotics but became chronic. Six months later a defect of the mucous membrane and exposure of the bone were noted in the same region where osteoradiomyelitis had developed previously. A CT scan revealed a wide range of osteomyelitis and a massive sequestrum in left mandible. We administered conservative therapy, because surgical intervention was refused by the patient. In this case, teoradionecrosis was thought to be induced and exacerbated by dental infection. Therefore, we feel it should be stressed that effective pre- and postradiation oral care should be provided to prevent and/or to alleviate osteoradionecrosis.放射線障害の最も重名篤なものとして放射線性骨壊死がある｡発症要因は照射線量、歯牙状態、腫瘍と顎骨との位置関係であり最近予防、緩和のために治療前後の口腔内管理の重要性が言われている｡今回、口腔内管理がうまく行かず臨床、画像的に歯性感染が誘因もしくは増悪因子と考えられた放射線性骨壊死の1症例を経験したので報告する｡症例は61歳男性、臨床診断は軟口蓋から口腔底に及ぶ扁平上皮癌(T4NOMO)、治療は6MeV lineacによる外照射56Gy、198Au grainによる組織内照射 60-75Gy相当を投入された。口腔内管理は放射線治療約2年後から行われたがその後も適切な管理が行えなかった｡管理開始から約10ヶ月後下顎左側臼歯部を中心とする放射線性骨髄炎を発症、抗生剤投与にて慢性化した｡骨髄炎発症から約1年6ヶ月後同部を中心とする粘膜欠損と骨壊死を発症し局所洗浄にて慢性化した。慢性化してから約6ヶ月後再び急性化、CTにて下顎左側臼歯部を中心とする下顎半側の広範な骨髄炎と腐骨像を認めた｡外科的処置を勧めたが本人の希望により行わず現在、慢性化している｡本症例は歯牙状態、骨変化の状態、粘膜障害と骨障害の重症度から歯性感染が放射線性骨壊死の誘因ないし増悪因子であると考えられた｡それ故に放射線治療前後の口腔内管理の重要性を痛感した