In accidents, the spines are generally subjected to one of five types of violence; pure flexion, flexion and rotation, extention, vertical compression, or direct shearing force by Holdsworth's report. Flexion and rotational violence, so-called, unstable rotational fracture-dislocation results in paraplegia commonly. The treatment of the fracture-dislocations of the thoracic and lumbar spine had varied widely during the past 100 years, including conservative and operative treatment, but there is no definitive study that convincingly show the superiority of either operative or nonoperative treatment till now. Ten cases of the unstable thoracolumbar vertebral fracture or fracture-dislocations during the past two years were reported in this paper. In unstable types on the thoracolumbar vertebral fracture or fracture-dislocations, direct blow was the most common cause of injury and the thoracolumbar junction extending from T10 to L1 was the most common location of injury in this report. Three among four paraplegic patients were received flexion and rotational violence and the remaining one, direct shearing force. All four paraplegic parients were operated. Among them two cases, the one who was performed open reduction and simple wire fixation and the other open reduction and Harrington instrumentation, recovered almost completely except mild motor weakness of lower extremities. All cases complained of remaining back pain more or less without relation to the method of treatment.