Osteoradionecrosis or osteonecrosis of the Temporal Bone
Osteoradionecrosis (ORN) of the temporal bone is the necrosis and exposure of the petrous temporal bone that does not heal for more than three months in patients with a history of radiation therapy.
Causes. The primary cause is high-dose radiotherapy or brachytherapy delivered around the petrous temporal bone for cancers of:
- Parotid gland
- External auditory canal
- Middle ear
- Maxilla
- Nasopharynx
- Pituitary gland
Pathogenesis. The petrous bone is dense and absorbs more radiation than soft tissues. It has a poor blood supply, particularly in the tympanic ring, making it vulnerable to necrosis. Radiation damages tissues by:
- Inhibiting mitosis and repair mechanisms
- Causing vasculitis of blood vessels
- Leading to avascular necrosis
Patients with microvascular diseases (e.g., atherosclerosis, diabetes) or trauma (e.g., dental extraction) are more susceptible.
Clinical Features. There are two types of osteoradionecrosis:
1. Localized Form
- Occurs when the petrous bone lies on the edge of the radiation field.
- Symptoms include mild ear pain (otalgia) and discharge (otorrhoea), with small areas of exposed bone in the external auditory canal.
- CT scans show small areas of bone sequestration.
2. Diffuse or Extensive Form
- This happens when radiation directly targets the petrous temporal bone.
- Symptoms are more severe, including intense pain and discharge.
- Complications include erosion of the facial canal, inner ear damage, and intracranial issues like brain abscesses, meningitis, or even death.
- CT scans reveal widespread bone destruction.
Management
1. Prevention
- Radiotherapy should be carefully planned.
- Surgical interventions should be scheduled before radiotherapy, allowing complete wound healing before radiation begins.
2. Treatment
Localized Form
- Managed conservatively by cleaning the ear and removing sequestra, local antibiotic application and analgesics for pain relief.
- Healing may take 1–4 years.
Diffuse or Extensive Form
- Requires radical surgical debridement and repair to prevent severe complications and promote healing.
- Hyperbaric oxygen therapy may be used, but its effectiveness is controversial.
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Osteonecrosis Best Lecture Notes Dr Rahul Bagla ENT Textbook
Reference Textbooks.
- Scott-Brown, Textbook of Otorhinolaryngology-Head and Neck Surgery.
- Glasscock-Shambaugh, Textbook of Surgery of the Ear.
- P L Dhingra, Textbook of Diseases of Ear, Nose and Throat.
- Hazarika P, Textbook of Ear Nose Throat And Head Neck Surgery Clinical Practical.
- Mohan Bansal, Textbook of Diseases of Ear, Nose and Throat Head and Neck Surgery
- Hans Behrbohm, Textbook of Ear, Nose, and Throat Diseases With Head and Neck Surgery.
- Salah Mansour, Middle Ear Diseases – Advances in Diagnosis and Management.
- Logan Turner, Textbook of Diseases of The Nose, Throat and Ear Head And Neck Surgery.
- Rob and smith, Textbook of Operative surgery.
- Anirban Biswas, Textbook of Clinical Audio-vestibulometry.
- Arnold, U. Ganzer, Textbook of Otorhinolaryngology, Head and Neck Surgery.
Author:
Dr. Rahul Bagla
MBBS (MAMC, Delhi) MS ENT (UCMS, Delhi)
Fellow Rhinoplasty & Facial Plastic Surgery.
Renowned Teaching Faculty
Mail: msrahulbagla@gmail.com
India
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