Delayed Post-Traumatic Osteonecrosis of the Vertebral Body (Kummell's Disease)

Pathogenesis: vascular watershed area involving the anterior vertebral body

Patient: middle-aged or elderly

Usual location: lower thoracic or lumbar vertebra

Clinical features:

(1) delayed onset after trauma, which may have seemed minor at the time

(2) painful angular kyphosis

(3) avascular necrosis of the anterior vertebral body

(4) MRI changes, including the vacuum cleft phenomenon and "double line" sign

(5) exclusion of other causes

Osteoporotic compression fractures need to be distinguished from Kummell's disease, but both can be present in the same patient.