title: Cervical Sagittal Alignment in Scheuermann Disease.
abstract: METHODS
  Retrospective evaluation of radiographs.
  
  
  OBJECTIVE
  The aim of this study was to assess sagittal cervical balance in patients with the two types Scheuermann disease (SD).
  
  
  BACKGROUND
  The structural hyperkyphosis characterizing SD may be localized in the thoracic (SDT) or thoraco-lumbar (SDTL) spine segments. This may affect sagittal cervical balance.
  
  
  METHODS
  Seventy-one patients (41 males and 30 females), aged 16.3 ± 3.8 years with SD, were enrolled into the study. On standing lateral long-cassette radiographs, the following measurements were made: C0-2 angle, C2-7 angle (CL), C1-C2 angle, relative rotation angle (RRA)-measured at levels from C2 to C7, cervical tilt (CT), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), C0-angle, cranial offset (CO), and cranial tilt (CRT). Comparison with t test was performed with significance level P < 0.05.
  
  
  RESULTS
  There were 38 SDT and 33 SDTL patients. In SDT, the T1 slope was significantly greater than that in SDTL (38.1° vs. 28.9°; P = 0.0002), and consequently CL (-19.8° vs. -8.9°; P = 0.0160), CT (29.8° vs. 24.3°; P = 0.0190), and TIA (81.9° vs. 71.1°; P = 0.0022) in SDT were significantly greater as well. The difference in CL was expressed mainly in C6-C5 (-4.8° vs. -1.4°; P = 0.0146) and C5-C4 (-4.4°; vs. -1.5° P = 0.0464) segments. There were no significant differences in proximal cervical lordosis: C0-2 angle (-21.6° vs. -20.8°; P = 0.7597), C1-C2 angle (-30.8°vs. -27.5°; P = 0.1746), C3-C2 (-5.4° vs. -5.1°; P = 0.7976), and C4-C3 (3.5° vs. -1.5°; P = 0.1464) segments. There was no significant difference in cranial parameters C0-angle, CRT, and CO.
  
  
  CONCLUSIONS
  Scheuermann disease type has an influence on cervical sagittal balance. Localization of structural kyphosis affects the T1 slope as well as C2-C7 lordosis, cervical tilt, and thoracic inlet angle. Significant difference in C2-C7 lordosis in comparison to similar C0-2 lordosis demonstrates that compensation is present in subaxial cervical spine. Position of the head center of gravity is not dependent on the SD type.
  
  
  METHODS
  4.
authors.affiliation: *Department of Orthopaedic Surgery, University of Illinois at Chicago, Chicago, IL †Department of Orthopedics, Pediatric Orthopedics and Traumatology, The Centre of Postgraduate Medical Education in Warsaw, Poland ‡Spine Disorders and Pediatric Orthopedics Department, University of Medical Sciences, Poznan, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Janusz
authors.forename: Marcin
authors.initials: M
authors.lastname: Tyrakowski
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kotwicki
authors.forename: Kris
authors.initials: K
authors.lastname: Siemionow
mesh_terms: D000293:Adolescent; D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D008141:Lordosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D004856:Postural Balance; D011859:Radiography; D012189:Retrospective Studies; D012544:Scheuermann Disease / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D055815:Young Adult