title: How to determine the upper level of instrumentation in Lenke types 1 and 2 adolescent idiopathic scoliosis: a prospective study of 132 patients.
abstract: BACKGROUND
  The selection of fusion levels continues to be controversial in adolescent idiopathic scoliosis (AIS). The classifications of King and Lenke remain the most widely used, but recent studies have demonstrated their shortcomings, including poor interobserver reproducibility. We propose a method of preoperative planning that is independent of anatomical classifications, based on the anticipated effect of curve reduction. The objectives of this preoperative strategy are (1) to achieve satisfactory T1 tilt and shoulder balance and (2) to restore balance in the coronal and sagittal planes. The purpose of the present study was to evaluate the results of our strategy of deciding the proximal level of arthrodesis in Lenke types 1 and 2 AIS.
  
  
  METHODS
  We included 132 adolescents operated on for thoracic AIS by posterior instrumentation. The choice of the proximal fusion level was based on preoperative analysis of the rigidity of the proximal curvature, T1 tilt, and shoulder balance. The preoperative, postoperative, and last follow-up radiographs were digitized then analyzed using computer software. Radiological parameters were compared using paired t tests.
  
  
  RESULTS
  Average age at the time of surgery was 15.2 years (SD, 1.7 years). Mean follow-up was 30.2 months. The clavicle angle and T1 tilt were significantly improved in both Lenke types 1 and 2 curves. No correlation was found between T1 tilt and shoulder balance. At last follow-up, 89% of the patients satisfied all criteria for balance.
  
  
  CONCLUSIONS
  The results of the present preoperative strategy, to which we adhered in 97% of cases, are encouraging and show that the systematic instrumentation of the entire proximal curvature is not justified in Lenke type 2 curves. However, long-term consequences of the residual T1 tilt need to be studied further.
authors.affiliation: Department of Pediatric Orthopaedic, Robert Debré Hospital, Paris 7 University, Paris, France. i_brice@hotmail.com
authors.forename: Brice
authors.initials: B
authors.lastname: Ilharreborde
authors.forename: Julien
authors.initials: J
authors.lastname: Even
authors.forename: Yan
authors.initials: Y
authors.lastname: Lefevre
authors.forename: Franck
authors.initials: F
authors.lastname: Fitoussi
authors.forename: Ana
authors.initials: A
authors.lastname: Presedo
authors.forename: Philippe
authors.initials: P
authors.lastname: Souchet
authors.forename: Georges-François
authors.initials: GF
authors.lastname: Penneçot
authors.forename: Keyvan
authors.initials: K
authors.lastname: Mazda
mesh_terms: D000293:Adolescent; D002968:Clavicle / Q000000981:diagnostic imaging; D020878:Device Removal / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D004856:Postural Balance; D011446:Prospective Studies; D011859:Radiography; D012600:Scoliosis / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery*; D012782:Shoulder / Q000000981:diagnostic imaging; D012984:Software; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome