An anterior instrumentation method of treating spinal deformities involves a combination of a spinal rod anterior system and one or two spinal plates fixed on the cephalad and caudal end vertebrae of the instrumented segment. Deformities are treated by the anterior rod system through compression, distraction and derotation. Two spinal plates are fixed to the cephalad and caudal end vertebrae respectively to prevent the end vertebrae from rotating into kyphosis. A number of cancellous screws are inserted into the cephalad and caudal end vertebrae and their adjacent vertebrae through the spinal plate to provide several points of fixation on the end vertebrae to prevent implant failure and loss of correction.