One of the challenges in treating malignancies is the side effects of radiation therapy applied to control malignancy, and the most problematic of these consequences occur in head and neck malignancies affecting the mandible.

Tissue injuries following radiotherapy in head and neck surgery are divided into three categories:

• Acute complications: which usually improve on their own and require only symptomatic treatment.
• Subacute complications: lasting for months and most commonly manifested as pneumonitis and spinal cord injuries (Lhermitte's syndrome).
• Delayed side effects: which occur after 6 months or more which never improve.

Certainly, there will be a continuation of the discussion about the delayed effects of radiotherapy, which requires special attention and highly advanced supportive therapies.

Etiology of delayed side effects of radiation therapy:

These complications are manifested by vascular changes (capillaries) and obstructive lesions of the end vessels, which are accompanied by the release of bioactive substances that lead to the release of fibro-genic cytokines and cause progressive fibrosis at the site of radiation therapy. Preventive attention Using hyperbaric oxygen therapy (HBOT) during the pre-delay period can prevent or reduce the delayed effects of radiotherapy.

Effects of Hyperbaric Oxygen Therapy (HBOT) on tissues undergoing radiation therapy:

Most of the research on the effects of HBOT on tissues affected by radiation therapy has been done by Dr. R. E. Marx at the University of Miami (head and neck surgeon) and the following positive and effective results are the result of his research:

1- Neovascularization ← Creation of new vessels at the capillary level

2- Increased vascular and cell mass at the site of radiotherapy

In addition to the above, the research of Dr. S. R. Thom (Pennsylvania - Philadelphia) reports an increase in nitric oxygen due to hyperbaric oxygen at the site of radiation therapy, which leads to the migration of stem cells to the site of injury.

The beneficial effects of hyperbaric oxygen in the treatment of osteoradionecrosis include:

• Angiogenesis in areas with vascular and hypoxic damage

• Reduction of fibrosis in tissues affected by radiation therapy

• Movement and stimulation of stem cells to the site of injury caused by radiation therapy

The third part can be considered the most important therapeutic response.

In the first decade of the 21st century, about half of the patients treated with hyperbaric oxygen in the United States were admitted for the purpose of preventing and treating the complications of radiation therapy. HBOT has been used extensively in tooth extraction in patients who have previously undergone radiation therapy and have been treated with hyperbaric oxygen to prevent ORN in the mandible. Academic studies on the effectiveness of this treatment have been started since 1970. Mr. Bedwiner reported that at radiotherapy doses less than 6000 / cGy, the prevalence of mandibular osteoradionecrosis (M.ORN) was almost zero, and at doses between 6000-7000 / cGy, the prevalence of M.ORN reached 1.8% and at doses higher than 7000 / cGy The prevalence of M.ORN increases to 9% (cGy = centyGray). Depending on the amount of radiotherapy performed, approximately 85% of the cases, the complications have improved spontaneously or only need supportive treatment. According to Dr. Marx, osteoradionecrosis due to radiotherapy is the result of aseptic avascular necrosis of the mandible, which is classified according to the severity of the necrosis that has occurred, and treatment is recommended based on this classification.

Stage I ORN:

At this stage, the lower jaw is free of mucus and becomes revealing. Treatment is with 30 days of hyperbaric oxygen daily before debridement and 10 days of HBO after superficial mandibular debridement.

‏Stage II ORN

At this stage, the mandible requires extensive debridement, and for more than 30 days, hyperbaric oxygen will be required after mandibular debridement. Pre-debridement sessions require 30 days.

‏Stage III ORN

At this stage, pathological fractures of the mandible or oral fistulas to the skin or lytic lesions are evident. Therefore, it is necessary to remove parts of the mandible and bone graft.

Hyperbaric oxygen is required 30 days before surgery and 10 days or more after surgery. In all these stages, hyperbaric oxygen is given 30 days before surgery to increase vascularity and cellularity as well as stem cell migration. In addition, these sessions are performed after surgery to complete the above effects in mandibular healing with clinical monitoring.

Other Cases

• Laryngous necrosis
• Chest wall necrosis
• Radiation myelitis nerve damage
• Brain necrosis, which is very rare and very dangerous.

In a study by Cluba et al., 10 cases of brain necrosis were studied in children. Despite hyperbaric oxygen therapy, 4 died but 6 survived. The treatment requires 30 to 60 days, which requires these sessions to be under pressure of 2.0-2.5ATA and the duration between 90 to 120 minutes with 100% oxygen respiration.

Cost check

In the United States, about 600,000 people receive radiation therapy each year, with between 1-5% experiencing dangerous complications of radiotherapy, of which about 50% require surgery and subsequent treatment. Hyperbaric oxygen therapy reduces the human and financial costs of this process. According to a 1992 study by Dr. Marx, treatment for hyperbaric oxygen-free complications cost $ 140,000 per person, while hyperbaric oxygen reduced the cost to $ 42,000 per person.