The Comparison of Strain Distribution on Thai Scoliosis and Thai Scoliosis Adjust by Screw Fixation System

The secondary curve (S-shape) is one of the scoliosis deformity types. Scoliosis usually occurs in the thoracolumbar region of the adolescents, adulthood and the elderly. If the patient is not advised and treated by the surgeon, the patient will be in more pain and the curvature of scoliosis will be increased. The screw fixation system or pedicle screw system is popular in the treatment of spinal deformity. Because the surgical treatment is highly considered as successful, the postoperative of the pedicle screw system will become virtual homogeneous vertebral and movement together; however, there are few studies reporting the post-operative results in Thai scoliosis surgery. Therefore, this study aims to analyse the strain of Thai scoliosis (S-shape) as compared with normal Thai spine and Thai scoliosis adjusted by screw fixation system under the compressive load with a finite element method. The results showed the maximum strain occurred on Thai scoliosis, normal Thai spine and Thai scoliosis adjusted by screw fixation system respectively. It appeared that the strain occurred on the model of scoliosis adjusted by screw fixation system were more decreased/reduced than the scoliosis model and it is reasonable if compared with the normal model, due to the pedicle screw fixation system could be absorbed the strain occurred on the spinal very well. The center of scoliosis pre-operative was at T7 and L1 levels which had the maximum displacement before being adjusted by screw fixation system. It affects the strain occurred on the models by the reaction force. As mentioned above, the patient should be advised and treated by the surgeon as quick as possible in order to return to daily activities better than before the surgery.