title: Segmental variations of bone mineral density in the cervical spine.
abstract: METHODS
  This study assessed the variability of segmental bone mineral density in the lower cervical spine (C4 through C7). A mean segmental bone mineral density value at each level was determined for all specimens, and a mean coefficient of variation among the 17 specimens was calculated.
  
  
  OBJECTIVE
  To quantify the degree of intersegmental bone mineral density variations within cadaveric lower cervical spine segments.
  
  
  BACKGROUND
  Bone mineral density studies in the thoracic and lumbar spine have shown a high degree of variability between spinal segments; however, the extent of segmental bone mineral density variability in the cervical spine is unknown.
  
  
  METHODS
  Seventeen human cadaveric cervical spine specimens (C4 through C7) were scanned in a water bath using dual energy x-ray absorptiometry in a lateral direction. Segmental bone mineral density of the vertebral bodies of all specimens were analyzed with respect to differences between segments within each specimen.
  
  
  RESULTS
  The mean coefficient of segmental bone mineral density variations within each specimen for all spines was 14.8% (range, 5.8%-22.9%). Bone mineral density mean values and ranges at each level were as follows: C4, 0.720 g/cm2 (range, 0.367-1.161 g/cm2); C5, 0.784 g/cm2 (range, 0.348-1.268 g/cm2); C6, 0.735 g/cm2 (range 0.367-1.450 g/cm2); C7, 0.590 g/cm2 (range, 0.340-1.040 g/cm2). Paired analysis of difference between all levels for 16 specimens demonstrated the bone mineral density at the C7 level to be significantly lower than at all other levels (P < 0.05).
  
  
  CONCLUSIONS
  Our data show that significant interlevel bone mineral density variability exists in the lower cervical spine, and suggests that random single segment bone mineral density sampling or mean specimen bone mineral density values may not be relevant.
authors: Baylor College of Medicine, Department of Orthopedic Surgery, Houston, Texas, USA.
authors: L J
authors: LJ
authors: Curylo
authors: R W
authors: RW
authors: Lindsey
authors: B J
authors: BJ
authors: Doherty
authors: A
authors: A
authors: LeBlanc
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015519:Bone Density / Q000502:physiology*; D002574:Cervical Vertebrae / Q000737:chemistry* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results