Apical Wiring Technique in Surgical Treatment of Adolescent Idiopathic Scoliosis The Intermediate Outcomes Between Lenke Types

Study Design: Retrospective cohort study of apical wiring technique for surgical treatment of adolescent idiopathic scoliosis patients. Objective: To evaluate the intermediate outcome of adolescent idiopathic scoliosis patients treated with apical wiring technique. Summary of Background Data: Regarding surgical treatment for adolescent idiopathic scoliosis, there are reports of the superiority of coronal plane correction using all-screw constructs compared with all-hook or hybrid constructs. Major limitations of all-screw constructs are thoracic hypokyphosis and increased proximal junctional kyphosis. There are few reports about apical wiring technique outcomes and no reports of this surgical technique comparing Lenke types. Methods: Consecutive adolescent idiopathic scoliosis patients treated with apical wiring technique were analyzed. Inclusion criteria were patient 21 years old or younger, who underwent a posterior only surgical correction with a follow-up of at least 2 years. Radiographic data were analyzed according to the criteria given by Lenke and colleagues. The radiographic parameters included global balance, Cobb angle, curve flexibility, apical vertebral translation, tilt angle of lower instrumented vertebra, angle of caudal disk to the lower instrumented vertebra, thoracic kyphosis, lumbar lordosis, and proximal junctional angle pre-operatively and postoperatively. Results: There was a significant improvement of Cobb angle in every Lenke type with an average correction of 74.6%. At latest follow-up, the average loss of correction was 3.5% (1.9 degrees). The greatest loss of correction for the minor curve of Lenke 2 was 14.1% (5.8 degrees). There was an improvement of thoracic kyphosis in hypokyphosis group (1.9-21.1 degrees; P < 0.001) and hyperkyphosis group (49.8-33.2 degrees; P = 0.001). Thoracic normokyphosis alignment was also preserved. No cases of abnormal proximal junctional kyphosis were noted in this cohort. Conclusions: Apical wiring technique for surgical treatment of adolescent idiopathic scoliosis provides an average correction of 71.1% at 3.4 years of average follow-up with harmonious sagittal plane correction even with preexisting abnormal thoracic kyphosis.