2. Definition of Radiation Necrosis of the Bone
● Radiation therapy is designed to target
and kill cancer cells. However, in the
process, it can also damage
surrounding healthy tissues, including
bone tissue.
● It's important to differentiate radiation
necrosis from other conditions, such
as infection or tumor recurrence, as
they may present with similar
symptoms.
3. Causes of Radiation Necrosis of the Bone
● Radiation necrosis occurs due to the
cumulative effect of radiation doses on bone
tissue. Over time, exposure to high doses of
radiation damages the DNA of bone cells,
leading to impaired cell function and cell death.
● The onset of radiation necrosis can vary from
months to years after radiation therapy,
depending on various factors such as the total
radiation dose and the sensitivity of the bone
tissue to radiation.
● The blood supply to the bone is also affected
by radiation therapy. Radiation can damage
the blood vessels, leading to decreased blood
flow and oxygenation of the bone tissue, which
further contributes to the development of
necrosis.
4. Common Symptoms
● Pain
○ typical symptom of radiation necrosis. The pain may worsen with movement or weight-bearing
activities.
● Swelling
○ localized edema and discomfort.
● Limited Range of Motion
○ stiffness and limited range of motion in the adjacent joints
● Fractures
○ Radiation-induced damage weakens the bone, making it more susceptible to fractures.
● Skin Changes
○ In some cases, changes in the overlying skin, such as redness, ulceration, or delayed wound
healing, may be observed.
● Neurological Symptoms
○ If radiation necrosis affects bones near nerves, it can lead to neurological symptoms such as
numbness, tingling, weakness, or difficulty in coordination.
● Infection
○ weakens the immune response and may increase the risk of developing infections
6. Treatment
● Conservative Management
○ NSAID, painkiller
○ Physical therapy
■ rehabilitation exercises can help improve range of motion, strengthen
muscles, and enhance overall function.
○ Assistive Devices
■ crutches, braces, or orthotics may be recommended to support the
affected bone and aid in mobility
● Debridement
● Stabilization
○ internal fixation
○ Bone grafting
● Joint Replacement
○ restore joint mobility
7. Prevention and Risk Reduction
● Proper Radiation Planning
○ Accurate and precise radiation planning is
crucial to minimize the risk of radiation
necrosis.
● Adherence to Treatment Guidelines
● Regular Follow-up and Monitoring
○ Close monitoring of the treated area,
prompt identification of any potential
complications or changes, and timely
intervention if necessary.
● Patient Education
○ Providing comprehensive education to
patients regarding the potential risks and
side effects of radiation therapy
9. Definition of MRONJ
● Medication-Related Osteonecrosis of the Jaw
(MRONJ) is a rare but serious condition
characterized by the death of bone tissue in
the jaw. It is primarily associated with the use
of certain medications, particularly
bisphosphonates and denosumab.
● MRONJ is characterized by the presence of
exposed bone in the oral cavity that fails to
heal. This can lead to pain, swelling, and
difficulty in performing everyday activities such
as chewing and speaking. The condition can
significantly impact a patient's quality of life
and require comprehensive management.
10. Medications cause MRONJ
● Bisphosphonates
○ A class of medications commonly prescribed to treat
conditions such as osteoporosis, bone metastases, and
other bone-related diseases.
○ Inhibiting bone breakdown and reducing the risk of
fractures.
○ Long-term use of bisphosphonates can lead to MRONJ.
○ Ex: alendronate, risedronate, ibandronate, zoledronic
acid
● Denosumab
○ A monoclonal antibody used in the treatment of
osteoporosis and bone-related malignancies.
○ Inhibiting the activity of cells that break down bone.
○ Increased risk of MRONJ
○ The risk of developing MRONJ is relatively low
11. Risk factors for MRONJ
● Prolonged use of medications
○ The risk of MRONJ tends to increase with the duration of treatment.
○ Long-term or high-dose use of bisphosphonates or denosumab
● High-dose or intravenous administration
○ Higher risk of MRONJ compared to oral forms
● Dental procedures
○ Dental extractions and invasive dental surgeries are potential triggers
for MRONJ.
● Poor oral hygiene
○ Contribute to the development and progression of MRONJ.
12. Symptoms of MRONJ
● Jaw pain and swelling
○ Persistent or worsening pain in the jaw is a significant symptom of MRONJ.
○ The pain may be localized to the affected area and can be continuous or
intermittent.
○ Swelling or inflammation in the jaw region may accompany the pain.
● Non-healing sores or exposed bone
○ MRONJ can cause non-healing sores or ulcers in the oral cavity, particularly in the gums or
jawbone.
● Loose teeth and difficulty in mouth opening
○ MRONJ can lead to loose teeth, which may cause discomfort or difficulties in
chewing and speaking.
○ Restricted mouth opening, known as trismus, can occur due to pain or
inflammation in the jaw area.
13. Diagnosis of MRONJ
● Clinical examination
○ The presence of exposed bone, non-healing sores, swelling, and signs of
infection are assessed.
● Patient history
○ Current and past medications, duration of treatment, and any dental
procedures performed, is crucial.
● Imaging techniques
○ X-rays
■ show areas of bone loss, changes in bone density, or the presence of
sequestra (dead bone fragments).
○ MRI
■ evaluate soft tissue involvement and detect any abscess formation
● Biopsy
