Osteoradionecrosis - A quick notes

Osteoradionecrosis is defined as “necrosis of bone due to obstruction of its blood supply.” It is the late effect of radiation therapy which results in irreversible tissue death and clinically observed as bony exposure for more than 3 months duration. Mandible is mostly affected and most often body of the mandible more than 60 Gy exposure. Additional clinical consequences of radiation include taste loss or altered taste sensation, changes to the periodontium and trismus 

The diagnosis of osteoradionecrosis is based on a history of radiation and clinical signs of severely painful, nonhealing exposed bone in the treatment area. Fistulae, sequestra, and pathologic fracture are other complications seen with osteoradionecrosis 

Risk Factors for Oseoradionecrosis

• Primary site of the tumor is primary radiation field 
• Nutritional status 
• Acute trauma  
• Ill-fitting tissue borne prosthesis 
• Concomitant chemo-radiation 
• Poor oral hygiene 
• Brachytherapy 
• Extraction of teeth in the area to be irradiated or already irradiated is considered to be the main risk factor in the development of osteoradionecrosis 
• Studies show an increased risk of osteoradionecrosis development when extractions are performed before radiotherapy 

Pathophysiology of Osteoradionecrosis

• Ewing in 1926 - Bone changes are associated with radiation therapy and described this disease state “radiation osteitis” 
• Watson and Scarborough in 1938 -  Radiation osteitis- caused by radiation, trauma and infection 
• Marx in 1980 - RT induces endarteritis that results in 3H – hypovascularity, hypoxia, hypocellularity 

Fibroatrophic Theory

By  Delanian and Lefaix 

Fibroblast proliferation undergoes total cellular depletion in response to radiation exposure aand shows reduced ability to produce and secrete collagen into the surrounding tissue. 

Patient related facts - (age, obesity) 

                                     - comorbidities (hypertension, diabetes) 

                                     - surgery in irradiated site 

                                     - chemotherapy and concomitant RT may intensify the acute and delayed reaction to RIF(Radiation induced Fibrosis) 

Medication-Related Osteonecrosis of the Jaw (MRONJ) can develop in a small subset of these patients.

Classically three criteria :

• Exposed oral bone where gingival or alveolar mucosa normally occurs 
• No history of head and neck radiation 
• Lasting for more than eight weeks 

Patients with MRONJ should be managed by professionals with experience in managing such lesions 

Precautions :

• 3D conformational radiation therapy 
• Intensity modulated radio therapy 
• Prophylactic oral care 

Preventive management for osteoradionecrosis

• Pre-radiation protocol 
• Intra-radiation protocol 
• Post-radiation protocol 

Therapeutic management of osteoradionecrosis

• Long-term antibiotics 
• Local wound irrigation 
• Debridement 
• Supportive treatment 
• Hyperbaric oxygen therapy 
• Home oral hygiene maintenance is essential; utilize oral rinses with chlorhexidine as needed 

 Recent developments

• Vascular directed therapy 
• Pentoxifylline and antioxidant therapy alpha - tocopherol (vitamin E) pentoxyfilline (PENTO) 
• Therapeutic ultrasound, bFGF, BMP-1 & BMP-2, distraction osteogenesis are also used in the management of ORN 

 Article by Dr. Siri P.B.