title: T1 slope and degenerative cervical spondylolisthesis.
abstract: METHODS
  Retrospective analysis.
  
  
  OBJECTIVE
  The main objectives of this study were to analyze and compare cervical sagittal parameters, including the T1 slope, in a population of 45 patients with degenerative cervical spondylolisthesis (DCS) and to compare these patients with a control group of asymptomatic population.
  
  
  BACKGROUND
  Sagittal balance in the cervical spine is as important as the pelvic incidence and is related to the concept of T1 slope. Compared with degenerative lumbar spondylolisthesis, there are few studies evaluating DCS, and characteristic changes of the cervical sagittal parameters (including T1 slope) in patients with DCS are not well studied.
  
  
  METHODS
  We identified 45 patients with DCS (5.8%) from a database of 767 patients, using cervical radiograph in a standing position. All had radiograph and computed tomographic scan at the same time. Cervical sagittal parameters were analyzed on computed tomographic scan in a standardized supine position. The following cervical sagittal parameters were measured: T1 slope, neck tilt, thoracic inlet angle, and cervical lordosis (C2-C7 angle). The DCS group was compared with a control group of 45 asymptomatic age- and sex-matched adults to the DCS group, who were studied in a recently published study.
  
  
  RESULTS
  Of our initial group of 767 patients, 45 with anterolisthesis (5.8%) were included for this study. The T1 slope was significantly greater for DCS (26.06° ± 7.3°) compared with the control group (22.32° ± 7.0°). No significant difference of the neck tilt, thoracic inlet angle, and C2-C7 angle was seen between the DSC group and the control group. Therefore, the T1 slope of the DSC group was significantly greater than that of the control group (P < 0.005).
  
  
  CONCLUSIONS
  The DCS group was characterized by a greater T1 slope than the control group; therefore, we suggest that a high T1 slope may be a predisposing factor in developing DCS.
  
  
  METHODS
  3.
authors.affiliation: Department of *Neurosurgery and †Orthopedics, Hallym University Sacred Heart Hospital, Anyang, Korea.
authors.forename: Hyo Sub
authors.initials: HS
authors.lastname: Jun
authors.forename: Ji Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Jun Hyong
authors.initials: JH
authors.lastname: Ahn
authors.forename: In Bok
authors.initials: IB
authors.lastname: Chang
authors.forename: Joon Ho
authors.initials: JH
authors.lastname: Song
authors.forename: Tae Hwan
authors.initials: TH
authors.lastname: Kim
authors.forename: Moon Soo
authors.initials: MS
authors.lastname: Park
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Kim
authors.forename: Seok Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Jae Keun
authors.initials: JK
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D011859:Radiography; D012189:Retrospective Studies; D013168:Spondylolisthesis / Q000000981:diagnostic imaging*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging*; D055815:Young Adult