Risk of osteoradionecrosis (ORN) is directly related to radiation dose and volume of tissue irradiated. The unilateral vascular supply to each half of the mandible results in postradiation ORN most frequently involving the mandible, compared with the maxilla. Presenting clinical features include:
- Diminished or complete loss of sensation.
Pathologic fracture can occur because the compromised bone is unable to appropriately undergo repair at the involved sites. Risk of tissue necrosis is in part related to trauma or oral infection; however, idiopathic cases can also occur. Patients who have received high-dose radiation to the head and neck are at lifelong risk for ORN, with an overall risk of approximately 15%.
Ideally, postradiation management or ORN is based on prevention that begins with comprehensive oral and dental care before radiation therapy begins. The dentition, periodontium, periapices, and mucosa should be thoroughly examined to identify oral disease, which could lead to serious odontogenic, periodontal, or mucosal infections that could necessitate surgical therapy postradiation. Oral disease should be eliminated pretreatment. Dentition that exhibits poor prognosis and is within high-dose fields should be extracted before radiation therapy begins. Ideally, at least 7 to 14 days should be allowed for healing before initiation of radiation; some have suggested allowing up to 21 days. Surgical technique should be as atraumatic as possible and use primary wound closure.
Patients who develop ORN should be comprehensively managed to:
- Eliminate trauma.
- Avoid removable dental prosthesis if the denture-bearing area is within the osteonecrotic field.
- Ensure adequate nutritional intake.
- Discontinue tobacco and alcohol use.
Topical antibiotics (e.g., tetracycline) or antiseptics (e.g., chlorhexidine) may contribute to wound resolution. Wherever possible, coverage of the exposed bone with mucosa should be achieved. Analgesics for pain control are often effective. Local resection of bone sequestra may be possible.
Hyperbaric oxygen therapy (HBO) is recommended for management of ORN, although it has not been universally accepted. HBO has been reported to increase oxygenation of irradiated tissue, promote angiogenesis, and enhance osteoblast repopulation and fibroblast function. HBO is usually prescribed as 20 to 30 dives at 100% oxygen and 2 to 2.5 atmospheres of pressure. If surgery is needed, ten dives of postsurgical HBO are recommended. Unfortunately, HBO technology is not always accessible to patients who might otherwise benefit because of lack of available units and the high price of care.