title: Key Vertebral Pedicle Screw Strategy for the Correction of Flexible Lenke Type 1 Adolescent Idiopathic Scoliosis: A Preliminary Study of a 5-year Minimum Radiographic Follow-up.
abstract: METHODS
  A retrospective clinical and radiographic study.
  
  
  OBJECTIVE
  The aim of this study was to evaluate outcomes of the key vertebral pedicle screw strategy (KVPSS) for the correction of flexible Lenke type 1 adolescent idiopathic scoliosis (AIS) with a minimum follow-up of 5 years.
  
  
  BACKGROUND
  The KVPSS has been described as an alternative screw placement strategy for surgically treating the main thoracic curve in AIS patients. However, there have been no long-term, three-dimensional correction studies of selective thoracic fusion using the KVPSS in Lenke type 1AIS.
  
  
  METHODS
  Twenty consecutive patients with Lenke type 1 main thoracic AIS underwent one-stage posterior correction and fusion using the KVPSS. Preoperative and postoperative radiographic and clinical parameters were analyzed.
  
  
  RESULTS
  The mean preoperative major thoracic curve was 47.4° ± 5.8°, and mean corrections of 67.0%, 63.4%, and 61.5% were observed at the immediate, 2-year postoperative, and final follow-ups, respectively. Thoracickyphosis decreased significantly from the preoperative period to the immediate postoperative period (P = 0.042) but did not change significantly from the 2-year postoperative follow-up to the final follow-up (P = 0.067). Apical vertebral rotation achieved 34.7% correction and exhibited correction loss of 8.2% at the final follow-up. The average intraoperative blood loss was 802.3 mL, and the mean operative time was 138.6 minutes. SRS-22 scores for self-image and satisfaction improved significantly from the preoperative period to the final follow-up. No neurologic or implant-associated complications were observed in this study.
  
  
  CONCLUSIONS
  The KVPSS is an effective method for correcting Lenke type 1 AIS and achieves satisfactory correction of the deformity. Relative to other approaches, the KVPSS can not only achieve a satisfactory and cost-effective clinical outcome but also reduce both operative time and intraoperative blood loss.
  
  
  METHODS
  4.
authors.affiliation: Department of Orthopaedic Surgery, the Affiliated Changhai Hospital of the Second Military Medical University, Shanghai, China.
authors.forename: Xian-Zhao
authors.initials: XZ
authors.lastname: Wei
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Zhou
authors.forename: Yi-Lin
authors.initials: YL
authors.lastname: Yang
authors.forename: Xi-Ming
authors.initials: XM
authors.lastname: Xu
authors.forename: Jing-Feng
authors.initials: JF
authors.lastname: Li
authors.forename: Yu-Shu
authors.initials: YS
authors.lastname: Bai
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Zhu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D016063:Blood Loss, Surgical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000473:pathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D065289:Pedicle Screws; D011183:Postoperative Complications; D011859:Radiography / Q000379:methods; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000601:surgery; D013123:Spinal Fusion / Q000379:methods; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D013997:Time Factors