Osteoradionecrosis

ORN is an inflammatory condition of bone that occurs after the bone has been exposed to therapeutic doses of radiation usually given for a malignancies.

1. Good morning

2. Osteoradionecrosis Guided by : Dr. Krushna pateria, Dr. Pooja wankhade Presented by : Mohammad Naved

3. Contents : Introduction Definition Etiology Clinical features Radiographic examination & features Differential diagnosis Management Prevention

4. Introduction This is inflammatory condition of bone. The high doses of radiation used in radiotherapy reduce drastically the vascularity and reparative powers of bone. The mandible is particularly susceptible. Subsequent trauma (e.g. tooth extraction) or infection may produce osteomyelitis with rapid destruction of the irradiated bone, sequestra formation and poor healing.

5. It is characterized by presence of exposed bone for a period of at least 3 months occurring at any time after delivery of the radiation therapy.

6. Definition Osteoradionecrosis refers to an inflammatory condition of bone (osteomyelitis) that occurs after the bone has been exposed to therapeutic doses of radiation usually given for a malignancy of the head and neck region.

7. Etiology Doses above 50 Gy usually are required to cause this irreversible damage. Bone that has been irradiated is hypocellular and hypovascular. Dental extraction and denture trauma after radiation therapy.

8. Clinical features Mandible is commonly affected than maxilla due to microanatomy & less vasculature. Posterior mandible is commonly affected than anterior portion because of radiation treatment for tumors in this region.

9. Loss of mucosal covering & exposed bone are hallmark of Osteoradionecrosis. Pain may or may not be present with swelling and drainage extraorally .. The exposed bone become necrotic as result of loss of vascularity from periosteum & sequestra.

10. Radiographic Features CT imaging is modality of choice. Early changes in bone: is well defined area of bone resorption within the outer cortical plate of mandible.

11. Later changes: lytic or sclerotic or mixture Location : Commonly posterior mandible Periphery : ill defined Internal structure : A range of bone formation and resorption occur. The bone pattern is granular.

12. Effects on surrounding structures : in rare cases stimulated periosteal bone formation resulting in bone formation on outer cortex. In the alveolar processes of maxilla and mandible there is irregular widening of periodontal membrane space .

13. EARLY LATER

14. Differential diagnosis Bone resorption stimulated by high level irradiation : Differentiated by absence of exposed bone. Chronic osteomyelitis : history of radiation therapy.

15. Management Conservative approach to maintain the integrity of inferior border of mandible, keeping the site free of infection , and patient free of pain is more successful. Adminstration of Antibiotics , rinisng Sequestrectomy, local debridement Use of narcotic analgesics , hydration, nutrition Ultrasound therapy can be used.

16. 2. Radical method HBO therapy Local debridement , sequestrectomy Mouth rinsing

17. Hyperbaric O2 therapy : breathing 100 % oxygen through facemask at 2.4 absolute atmospheric pressure for 90 minutes 5 days week. HBO reduced the hypoxia and increase healing by increase in arterial and venous O2 tension.

18. Prevention of ORN Pre irradiation care : Extraction of periodontally compromised tooth which is in direct beam of radiation. During therapy : mouth rinse with 0.2 % chlorhexidine. Post irradiation care : Avoidance of denture use. Use of salivary substitutes.

19. Summary Osteoradionecrosis is caused by bone exposed to irradiation therapy above 50 Gy. It is a radiation induced, non healing, hypoxic wound. Its prevention and treatment are possible. HBO therapy , Sequestrectomy are some methods of treatment.

20. References White and pharoh Rajiv M borle . Textbook of oral and maxillofacial surgery. Jaypee . 1 st edition 2014.

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