Secondary atlanto-odontoid osteoarthritis with osteoradionecrosis of upper cervical spine mimicking metastasis.

Osteoradionecrosis (ORN) is a known entity in patients with head and neck malignancy treated by radiotherapy. Involvement of mandible (0.8-37%) and maxilla (2-11%) is quiet common but upper cervical spine involvement is rare. One needs to have a high index of suspicion for the diagnosis of ORN after radiotherapy in the head and neck region. It may mimic either metastasis or an infection and needs histopathology to make definitive diagnosis. We reported the successful treatment of a patient with ORN involving upper cervical spine by posterior decompression and stabilisation. In addition, a new technique of reaching the odontoid process from posterior aspect for biopsy has been described.