The purposes of this study are to make an operative treatment option of thoracolumbar burst fractures by the degree of initial kyphotic deformity or by the degree of initial loss of anterior vertebral height. We analyzed sixty-three cases of one segmental thoracolumbar bursting fractures treated surgically by posterior or posterolateral fusion with short segmental transpedicular screws fixation method using Diapason or CD from January, 1992 to October, 1996. Indications of operative treatment were that the degree of initial kyphotic deformity was above 15degreesor initial loss of anterior vertebral height was above 30%. Minimum follow-up period was 12 months and the results were as follows : 1. Entirely, mean kyphotic angle was 21.6degreesinitially, 11.3degreespostoperatively and 14.2degrees at the end of follow-up. Mean anterior vertebral height was 59.6% initially, 83.8% postoperatively and 80.8% at the end of follow-up. So 10.3degrees , 24.2% was corrected postoperatively and loss of correction was 2.9degrees , 3% at the end of follow-up. 2. In the respect of the degree of initial kyphotic deformity, when compared above 30degrees with below 30degrees , loss of correction was 7.3degrees , 1.4degrees at the end of follow-up respectively and this result had significant difference between these two groups statistically. 3. In the respect of initial loss of anterior vertebral height, when compared above 55% with below 55%, loss of correction was 7.7%, 2.2% at the end of follow-up respectively and this result had significant difference between these two groups statistically. 4. In the respect of time interval from injury to operation, when compared within 2 weeks with after 2 weeks, respectively loss of correction was 1.7-2.2degrees , 3-3.9% and 4.1degrees , 6.7% at the end of follow-up and this results had significant difference between these two groups statistically. These data suggested if initial kyphotic angle is below 30degrees or initial loss of anterior vertebral height less than 55%, short segmental transpedicular screw fixation provide sufficient stability but if initial kyphotic angle is above 30degrees or initial loss of anterior vertebral height is above 55%,additional anterior interbody fusion may be considered.