preservation of thoracic kyphosis is critical to maintain lumbar lordosis in the surgical treatment of adolescent idiopathic scoliosis

restoration of the sagittal alignment is one of the fundamental goals in scoliosis correction surgery. having an increase in popularity of segmental spinal instrumentation, thoracic kyphosis (tk) is often sacrificed to achieve frontal and axial plane correction. patients with a lenke type 1 deformity underwent selective thoracic fusion (lowest instrumented vertebra of t12 or l1) using corrective segmental spinal instrumentation (hook-rod) and were followed up for 2 years. they were evaluated before and after operation for coronal and sagittal alignments using standing anteroposterior and lateral radiographs. there were 63 patients (21 male, 42 female) with a mean age of 15.8±2.1 years included to this study. tk reduction had significant correlation (p≤0.001) with lumbar lordosis (ll) decrease at preoperative (r=0.47), immediately postoperative (r=0.37) and at 2-year follow-up (r=0.5). the decrease in ll after 2-years was less than decrease in tk (4.5±8.5 vs 6±10, respectively).