title: Importance of Distal Fusion Level in Major Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis Treated by Rod Derotation and Direct Vertebral Rotation Following Pedicle Screw Instrumentation.
abstract: METHODS
  A retrospective comparative study.
  
  
  OBJECTIVE
  The aim of this study was to analyze the exact distal fusion level in the treatment of major thoracolumbar and lumbar (TL/L) adolescent idiopathic scoliosis (AIS) using rod derotation (RD) and direct vertebral rotation (DVR) following pedicle screw instrumentation (PSI).
  
  
  BACKGROUND
  Proper determination of distal fusion level is a very important factor in deformity correction and preservation of motion segments in the treatment of major TL/L AIS.
  
  
  METHODS
  AIS patients with major TL/L curves (n = 64) treated by PSI with RD and DVR methods with a minimum 2-year follow-up were divided into AL3 (flexible) and BL3 (rigid) according to the flexibility and rotation by preoperative bending radiographs.
  
  
  RESULTS
  There was no significant difference in TL/L (major) curve between the AL3 and BL3 groups postoperatively (P = 0.933) and at the last follow-up (P = 0.144). In addition, there was no significant difference in thoracic (minor) and compensatory (caudal) curve postoperatively (thoracic curve: P = 0.828, compensatory curve: P = 0.976); however, there was a significant difference in compensatory (caudal) curve at the last follow-up (P = 0.041). The overall prevalence of unsatisfactory results was 28.1% (18/64 patients), and the prevalence was 15.2% (7/46) in the AL3 group and 61.1% (11/18) in the BL3 group, which was significantly different (P < 0.05).
  
  
  CONCLUSIONS
  Lowest instrumented vertebra (LIV) would be selected at L3 (EV) when the curve is flexible; L3 crosses CSVL with a rotation of less than grade II in preoperative bending radiographs. However, if the curve is rigid, LIV should be extended to L4 (EV + 1) in order to prevent the adding-on phenomenon in the treatment of major TL/L AIS using RD and DVR following PSI.
  
  
  METHODS
  4.
authors.affiliation: Department of Orthopaedic Surgery, Sanggye Paik Hospital, College of Medicine, The Inje University, Seoul, Korea.
authors.forename: Dong-Gune
authors.initials: DG
authors.lastname: Chang
authors.affiliation: Department of Orthopaedic Surgery, Korea University Guro-Hospital, College of Medicine, The Korea University, Seoul, Korea.
authors.forename: Jae Hyuk
authors.initials: JH
authors.lastname: Yang
authors.affiliation: Department of Orthopaedic Surgery, Sanggye Paik Hospital, College of Medicine, The Inje University, Seoul, Korea.
authors.forename: Se-Il
authors.initials: SI
authors.lastname: Suk
authors.affiliation: Department of Orthopaedic Surgery, Korea University Guro-Hospital, College of Medicine, The Korea University, Seoul, Korea.
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Suh
authors.affiliation: Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, The University Hospital for Albert Einstein, Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Woojin
authors.initials: W
authors.lastname: Cho
authors.affiliation: Department of Orthopaedic Surgery, Sanggye Paik Hospital, College of Medicine, The Inje University, Seoul, Korea.
authors.forename: Yeon-Seok
authors.initials: YS
authors.lastname: Jeong
authors.affiliation: Department of Orthopaedic Surgery, Sanggye Paik Hospital, College of Medicine, The Inje University, Seoul, Korea.
authors.forename: Jin-Hyok
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kee-Yong
authors.initials: KY
authors.lastname: Ha
authors.affiliation: Department of Orthopaedic Surgery, Kyung Hee Hospital, College of Medicine, The Kyung Hee University, Seoul, Korea.
authors.forename: Jung-Hee
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D065289:Pedicle Screws / Q000639:trends*; D012189:Retrospective Studies; D012399:Rotation; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation / Q000639:trends*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome