Osteoradionecrosis

Osteoradionecrosis is bone death due to radiation. The bone dies because radiation damages its blood vessels.

Osteoradionecrosis is a rare side effect that develops some time after radiation therapy has ended. It usually occurs in the lower jaw, or mandible. The lower jaw is at risk of osteoradionecrosis because it has a limited blood supply. Very rarely, osteoradionecrosis can start in the upper jaw, or maxilla.

Doctors usually classify osteoradionecrosis based on what tissue it affects, if it responds to treatment and if it has caused a fracture. They give osteoradionecrosis a grade from 1 to 3, usually as a Roman numeral (I, II or III). They use these grades to plan treatment.

Osteoradionecrosis is caused by radiation therapy to the bone. It may develop years after radiation therapy for head and neck cancers.

The risk of developing osteoradionecrosis increases when the dose of radiation received is greater than 60 grays. It is also higher if the bone treated with radiation is exposed.

There is also a higher risk of developing osteoradionecrosis if a dental exam and necessary dental repairs aren’t done before radiation therapy. People with poor oral hygiene before or after radiation therapy are also at higher risk. So are people who develop dry mouth after radiation therapy.

Damage or trauma to the jaw after radiation therapy, especially within the first year after treatment, can also increase the risk for osteoradionecrosis. Damage or trauma can be caused by:

• tooth extraction
• cancer surgery or biopsy
• denture irritation
• accidents

In rare cases, osteoradionecrosis may develop even if there isn’t any trauma or damage to the mouth, teeth or jaw.

Symptoms can vary depending on the grade or extent of the osteoradionecrosis and include:

• pain
• swelling
• a sore, or ulcer, in the mouth or on the jaw
• difficulty opening the jaw, or trismus
• an abnormal opening, or fistula, between the jaw and the surface of the body
• less feeling in the mouth or jaw, or even a complete loss of sensation in the area
• infection
• teeth that aren’t aligned properly, which is called malocclusion
• jaw fracture not related to an accident or other trauma
• exposed bone inside the mouth
• bone sticking out through the skin, which is called sequestrum

Exposed bones and sequestrum are most often found under the jaw.

Report symptoms to your doctor or healthcare team as soon as possible.

Your doctor will try to find the cause of osteoradionecrosis. This usually includes doing a physical exam, including a complete head and neck exam. Your doctor may also review your medical records to find out the total dose of radiation you received and the area that was treated.

You may also need the following tests:

• x-ray of the whole jaw
• CT scan
• MRI
• biopsy of the area to check if the cancer has come back or a second cancer has developed

Find out more about these tests and procedures.

Your healthcare team will take steps to prevent osteoradionecrosis. The following measures should be taken before and after radiation therapy.

Visit your dentist for a thorough dental exam and teeth cleaning before you have radiation therapy. If you need to have any teeth removed or cavities filled, do so before radiation therapy.

You should also start using daily fluoride treatments. Talk to your dentist or healthcare team about these treatments.

Be sure to practise good oral care before and after treatment. Keeping the teeth and gums healthy is important for proper healing. Also eat a healthy diet, including foods and beverages that are low in sugar.

Have regular dental exams. Be sure to have any cavities filled or infections in the mouth treated as soon as possible. If a tooth needs to be removed, wait until after radiation therapy is complete.

Your dentist or healthcare team will recommend fluoride treatments to help prevent cavities. If you have dry mouth, they will also suggest ways to replace saliva and keep your mouth moist.

Once the extent of osteoradionecrosis is known, your healthcare team can suggest ways to treat it. You will also be given antibiotics if there is an infection in the bone. Other treatment options may include the following measures.

Your doctor may need to do surgical debridement. This means removing dead or infected tissue from around a wound. Dead, or necrotic, bone may also need to be removed. This is called sequestrectomy.

Depending on where osteoradionecrosis develops and how far it progresses, your doctor may need to do surgery to help restore the area. This may include microvascular reconstructive surgery to restore blood flow to the area. Bone grafts may be needed to replace the sections of the jawbone that are removed. Soft tissue grafts can be used to replace muscle and other tissues that have been removed. You may also need dental implants if teeth are removed.

Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room. It is done in a special chamber where the pressure inside is higher than the normal pressure of the atmosphere. The higher pressure allows more oxygen to get into your blood, which can help heal damaged and infected tissues.

Hyperbaric oxygen therapy is used in combination with wound care and surgery. The treatment plan often includes 20 treatments before surgery and 10 more treatments after surgery. This treatment plan may be adjusted based on your personal situation and how well the osteoradionecrosis responds to the hyperbaric oxygen therapy.

After you finish radiation therapy, your healthcare team may recommend that you have hyperbaric oxygen therapy before you have any teeth removed.

Hyperbaric oxygen therapy may not be available in all centres.