Burst fractures typically occur at T12 or L1 and create a sagittal deformity by a compression mechanism. This posttraumatic kyphosis is evaluated preoperatively by measuring the sagittal index of Farcy. Posterior instrumentation using in situ contouring is based on a bilateral insertion of rods which take the shape of the spine first. The rods are placed in a perpendicular position to monoaxial pedicular screws and then bent in situ, which makes the spine follow the movements of the rods. This principle makes it possible to correct the posttraumatic kyphosis at the level of the fractured vertebra and the overlying disk, which will open progressively using a ligamentotaxis mechanism. An additional anterior approach is indicated if the sagittal correction through the disk represents less than 50% compared to the total correction (in other words, if the correction of the traumatic deformity is obtained more in the disk than in the bone (>50%), an additional anterior approach is performed: more through the disk than the vertebral body (>50%)). This reliable technique meets the requirements of sagittal posttraumatic kyphosis correction, and provides a solid construct which avoids bracing.