Osteoradionecrosis is the death of bone due to radiation. The bone dies because of damage to its blood vessels caused by the radiation.
Osteoradionecrosis is a rare late effect that occurs after radiation therapy has ended. The lower jaw (mandible) is the most common bone affected. The lower jaw is at risk of osteoradionecrosis because of its limited blood supply. Very rarely, osteoradionecrosis can start in the upper jaw (maxilla).
Osteoradionecrosis may be described by 3 categories:
- grade I – there is exposed bone due to the death of soft tissue covering the bone
- grade II – osteoradionecrosis that has not responded to treatment
- grade III – osteoradionecrosis that involves the whole thickness of the bone, has caused a fracture or both
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Causes
Osteoradionecrosis may be caused by radiation to the bone. It may develop years after radiation therapy for head and neck cancers.
The risk of developing osteoradionecrosis may increase when:
- The person had poor oral hygiene or did not receive a dental evaluation and dental repair before radiation treatment was begun.
- Chemotherapy was given along with radiation therapy (chemoradiation).
- The dose of radiation received was greater than 70 grays (gray is the unit used to describe the amount of radiation absorbed).
- There is damage or trauma to the jaw after radiation therapy has finished, especially within the first year after treatment:
- tooth extraction
- cancer surgery or biopsy
- denture irritation
- accidents
- A person experiences dry mouth after radiation therapy for head and neck cancer.
- A person has poor oral hygiene after treatment has been completed.
- The risk of developing osteoradionecrosis can be reduced with good oral health care.
Spontaneous osteoradionecrosis may rarely occur without any trauma or damage to the mouth, teeth or jaw.
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Symptoms
Symptoms of osteoradionecrosis include:
- pain
- swelling
- a sore or ulcer in the mouth or on the jaw
- inability to open the mouth (trismus)
- exposed bone inside the mouth or protruding through the skin (sequestrum)
- a sequestrum is most commonly found under the jaw
- jaw fracture not related to an accident or other trauma
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Diagnosis
Diagnostic tests will be done if the signs and symptoms of osteoradionecrosis are present or if the doctor suspects osteoradionecrosis. Tests may include:
- physical examination, including a complete head and neck exam
- a special x-ray of the whole jaw called a Panorex
- computed tomography (CT) scan
- biopsy of the area – to rule out a recurrence of the cancer or a second cancer
A person's medical record may also be examined to find out the total dose of radiation that was received during radiation therapy, the radiation techniques used and the area that was treated.
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Management
Osteoradionecrosis may be managed by the following.
Surgery
The types of surgery that may be used are:
- surgical debridement
- removal of all the dead, infected tissue around the soft tissue wound, leaving a margin of healthy tissue
- sequestrectomy
- removal of dead (necrotic) bone
- microvascular reconstructive surgery
- bone grafts to replace the sections of the jawbone that have been removed
- soft tissue grafts to replace muscle and other tissues that have been removed
Antibiotics
Antibiotics may be given if there is an infection.
Hyperbaric oxygen therapy
Hyperbaric oxygen therapy is done with a special pressure chamber. A person sits in the chamber, and the pressure inside is increased above the normal pressure of the atmosphere. At higher pressure, more oxygen gets into a person's blood. Higher levels of oxygen can improve healing of damaged and infected tissues.
Hyperbaric oxygen therapy is used in combination with wound care and surgery. The most common way of giving hyperbaric oxygen therapy is the Marx protocol:
- 20 treatments in the hyperbaric chamber before surgery
- surgery (debridement, sequestrectomy and/or reconstructive surgery)
- 10 more treatments after surgery
This treatment plan may be adjusted for the person's situation and how well the osteoradionecrosis responds to the hyperbaric oxygen therapy.
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Follow-up
People who have had radiation therapy for head and neck cancers are at an increased risk of developing osteoradionecrosis for the rest of their lives. It is important to practise good oral health care and report any signs and symptoms of osteoradionecrosis to the dentist or oncologist.
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