Osteoradionecrosis
Pronunciation: os-tee-oh-ray-dee-oh-neh-KROH-sis
Also written as: ORN — Osteoradionecrosis
A serious complication of radiotherapy in which irradiated bone — most commonly the mandible — undergoes avascular necrosis due to radiation-induced damage to the bone's vascular and cellular components.
Full Definition
Osteoradionecrosis (ORN) arises when bone that has received a significant radiation dose fails to heal following trauma, surgery, or spontaneously, due to hypovascularity, hypoxia, and hypocellularity induced by ionising radiation. The mandible is predominantly affected because of its relatively poor blood supply compared with the maxilla. ORN is staged using systems such as the Store classification. It is critically distinct from MRONJ (medication-related osteonecrosis of the jaw), which shares similar clinical features but has a different aetiology (bisphosphonate or antiangiogenic drug exposure). Editors must not conflate ORN with MRONJ in any clinical or medico-legal document, as the distinction affects treatment planning and liability.
Usage
Usage note: Expand 'ORN' on first use in all formal documents. Rigorously distinguish from 'MRONJ', which has a pharmacological rather than radiation aetiology.
In Context
- "The case report documented Stage III osteoradionecrosis of the mandible following post-ablative radiotherapy for squamous cell carcinoma." — Clinical Case Report
- "Editors must verify that 'osteoradionecrosis' is not abbreviated to ORN without definition on first use." — Journal Manuscript