| Objective:To evaluate the effects of classification systems on the selection of thoracic curve fusion and lowest instrumented vertebrae(LIV) in the surgical treatment of adolescent idiopathic scoliosis(AIS) for Lenke type 1 curves.Methods:Fifty-two AIS patients with Lenke type 1 curves operated between 2002 and 2007 were included and classified retrospectively according to the King and Lenke classification systems among whom 41 were female and 11 were male.Their average age was 15.5 years(11-18 years) at operation.Preoperative standing posteroanterior(PA) and lateral radiographs,preoperative right and left supine bending radiographs,and the instant and latest postoperative standing PA and lateral radiographs were reviewed.Before operation,the Cobb angle of the thoracic curve was averaged 53°and the curve flexibility was averaged 40%.The Cobb angle of lumbar curve was averaged 35°and the curve flexibility was averaged 84%.All patients were operated with posterior-only approach among whom 23 curves were corrected by CD technique and 29 curves were corrected by thoracic pedicle screw technique.The LIV of each patient was identified with King and Lenke classification systems respectively.Results:With a follow-up of 12-38 months,the thoracic curves were corrected to an average of 20°(correction rate 64%) and the correction loss was an average of 2.7°at the final follow-up.The lumbar curves were corrected automatically to an average of 11°(correction rate 70%) and the correction loss was an average of 2.4°at the final follow-up.Compared with the King system,the LIVs recommended by Lenke system were more consistent with our actual LIVs.No spinal imbalance was clinically observed in all the patients.Conclusion:The rules recommended by Lenke system for selective fusion are more reliable.The rules used in this article for the selection of LIVs in Lenke type 1 patients help to obtain good results in the clinical operations. |
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