Background: Adolescent idiopathic scoliosis (AIS) is abnormal spinal alignment in 3 planes: the coronal, sagittal and rotational planes, and one of the methods used for its treatment is surgical correction. In the present day, the most common
surgical techniques used to correct spinal alignment are simple rod derotation and direct vertebral derotation.
Objective: To compare spinal alignment results after surgical correction with simple rod derotation and direct vertebral
derotation.
Material and Method: We retrospectively enrolled 29 AIS patients who had undergone surgical correction using simple rod
derotation or direct vertebral derotation at Rajavithi Hospital, Bangkok, Thailand between January 2012 and December 2014. This study was conducted by a single surgeon, and the surgical technique was chosen according tothe surgeon’s preference. X-ray and CT scan of whole spine were used by an interobserver to measure parameters such as apical vertebral rotation angle, coronal and sagittal vertebral alignment, lower instrument vertebral tilt and shoulder balance,and to compare the results of the two groups.
Results: There was a significant improvement in overall spinal alignment parameters postoperatively in both groups, but there was no significant difference in apical vertebral rotation or thoracic kyphosis in the simple rod derotation group. There
was no significant difference between overall spinal alignment of the two groups.
Conclusion: Both surgical techniques showed improvement in overall spinal alignment; however, no significant difference
between these improvements was found in the two groups.

Keywords: Adolescent idiopathic scoliosis, Surgical correction, Simple rod derotation, Direct vertebral rotation