title: Convex-Rod Derotation Maneuver on Lenke Type I Adolescent Idiopathic Scoliosis.
abstract: BACKGROUND
  Convex-rod derotation may have potential advantages for adolescent idiopathic scoliosis (AIS) correction; however, study of this technique has been limited.
  
  
  OBJECTIVE
  To compare the radiographic outcomes of Lenke type I AIS patients treated by the convex- or concave-rod derotation maneuvers.
  
  
  METHODS
  A retrospective study was designed to compare 2 cohorts, including 81 Lenke type I AIS patients treated with convex-rod derotation (n = 38) or concave-rod derotation (n = 43), between July 2008 and September 2012. All patients had complete clinical records and radiographic data, which were collected and compared between groups.
  
  
  RESULTS
  In comparing 9 radiographic parameters, significant differences were found in the incidence of screw misplacement, the postoperative main-curve angle, and the corrective rate between groups. The major-curve angles in both the convex- and the concave-rod derotation groups were corrected from 54.0° ± 10.6° and 53.0° ± 11.1° preoperatively, to 8.5° ± 6.9° and 12.9° ± 6.8° postoperatively, with corrective rates of 85.3% and 76.0%, respectively (P = .001). Final T5-T12 kyphosis and appropriate coronal-to-sagittal balance were achieved in both groups. The incidence of screw misplacement in the convex and concave sides of all patients was 1.8% and 3.7%, respectively (P = .047), and 1.8% and 3.6%, respectively, in the convex- and the concave-rod derotation groups (P = .044).
  
  
  CONCLUSIONS
  Compared with concave-rod derotation, convex-rod derotation can potentially improve the major-curve corrective rate and tends to reduce the risk of pedicle breach in Lenke type I AIS patients.
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Huang
authors.initials: H
authors.lastname: Zifang
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Hengwei
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Deng
authors.initials: D
authors.lastname: Yaolong
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Sui
authors.initials: S
authors.lastname: Wenyuan
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Qifei
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Cao
authors.initials: C
authors.lastname: Lei
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Fobao
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Spine Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Junlin
mesh_terms: D000293:Adolescent; D001863:Bone Screws / Q000009:adverse effects; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000601:surgery; D008297:Male; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000453:epidemiology; D011184:Postoperative Period; D012189:Retrospective Studies; D012600:Scoliosis / Q000601:surgery*; D013131:Spine / Q000601:surgery*
keywords: Concave-rod derotation; Convex-rod derotation; Correction; Kyphosis; Scoliosis