title: The Position of the Aorta Relative to the Vertebrae in Patients With Lenke Type 1 Adolescent Idiopathic Scoliosis.
abstract: METHODS
  A computed tomography study.
  
  
  OBJECTIVE
  The aim of the study was to clarify the position of the aorta relative to the spine in patients with Lenke type 1 adolescent idiopathic scoliosis.
  
  
  BACKGROUND
  Several authors have examined the position of the aorta in patients with scoliosis; however, their analysis included several types of curve. There is a possibility that the position of the aorta differs according to the scoliosis curve type.
  
  
  METHODS
  Thirty-eight patients with Lenke type 1 were analyzed. The angle (left pedicle aorta [LtP-Ao] angle) and distance (LtP-Ao distance) from the insertion point of the left pedicle screw to the aorta were measured from T4 through L2. The measured data were evaluated from 4 levels above to 4 levels below the apical vertebra. The difference between lumbar modifiers A and C was examined. Dangerous pedicles, which were defined as those in which the aorta entered the expected area based on the screw direction error and length, were counted from T10 to L2.
  
  
  RESULTS
  The aorta was located posterolaterally and adjacent to the vertebra at the middle thoracic level, and anteromedially and distant at the thoracolumbar level. LtP-Ao angle was largest at 1 level above the apical vertebra, and LtP-Ao distance was shortest at 2 levels above. LtP-Ao angle of Lenke 1A was significantly larger than 1C from T11 to L2, and LtP-Ao distance of 1A was significantly shorter than 1C from T11 to L1. When the screw length was 40 mm and the direction error was within 10°, there were a large number of dangerous pedicles at T11, regardless of the lumbar modifier.
  
  
  CONCLUSIONS
  The direction error has a potential risk of injuring the aorta around the apical vertebra. The selection of screws of the proper length is necessary to avoid a breach of the anterior vertebral wall at thoracolumbar level, especially at T11.
  
  
  METHODS
  3.
authors.affiliation: *Graduate School of Medical Sciences, Department of Orthopaedic Surgery, Kyushu University, Fukuoka †Department of Orthopaedic Surgery, Kyushu University Beppu Hospital, Oita, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Bekki
authors.forename: Katsumi
authors.initials: K
authors.lastname: Harimaya
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Hayashida
authors.forename: Seiji
authors.initials: S
authors.lastname: Okada
authors.forename: Toshio
authors.initials: T
authors.lastname: Doi
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D065289:Pedicle Screws; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000601:surgery; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult