Clinical observation was made on 131 cases of the unstable spine injury treated at the Orthopedic Surgery Department of Busan National University Hospital during the period from January 1974 to December 1981. The results obtained were as follows: 1. More than two-thirds of patients were between the age of 20 and 40, and the proportion of males to females showed a ratio of 5.9 to 1. The most common cause of injury was falling at an industrial area, rating 64.1% of all cases. 2. Fracture level was observed 31.3% in the first lumbar level, 24.4% in the twelfth thoracic vertebra, and 67.9% between the twelfth thoracic vertebra and the second lumbar vertebra. 3. Mechanisms of injury were 44.3% by pure flexion, 26.7% by flexion and rotation, 15.3% by direct shearing force, and 13.7% by vertical compression. 4. The fracture with lower extremity paralysis was due to the rotational fracture dislocation, which comprised 66% of all. 5. Kyphosis increased to the average of 10.6 degree in the case of decompressive laminectomy and of 3.4 degree in the case of spinal fusion. 6. The anatomical alignment and a definite stability could be obtained by the use of Harringtons rod in the cases of the unstable thoracolumbar fracture and fracture-dislocation. In 3 cases of all, we could get satisfactory results 1 month after the day injury occured. 7. In case of complete paralysis of lower extremity, it was found only 9.4% showed partial recovery, neurologically, and 61.9% of the patients with incomplete paralysis were also partly recovered. 8. The most common complication was urinary tract infection, which comprised 83% of the cases. With the use of intermittent urinary catheterization, the voiding reflex recovered within 4 months in most cases.