title: Trabecular bone structure in lumbosacral transitional vertebrae: distribution and densities across sagittal vertebral body segments.
abstract: BACKGROUND
  Lumbosacral transitional vertebrae (LSTV) are associated with altered articular morphology at the L5-S1 junction. Studies related to lumbo-sacral trabecular architecture in LSTV are few. Altered lumbosacral load bearing at these anomalous junctions possibly results in changes in the number, density, and trajectory of the trabecular bone in transitional lumbosacral vertebral bodies.
  
  
  OBJECTIVE
  To investigate the pattern, distribution, and density of trabecular bone in the terminal lumbar vertebrae and the first sacral segments in LSTV-affected spines. Measurements were compared with those obtained from normal lumbosacral specimens.
  
  
  METHODS
  Observational and descriptive human cadaveric study of vertebral trabecular architecture.
  
  
  METHODS
  Blocks of tissues were obtained from normal (n=20) and LSTV cadaveric specimens (n=16) by sectioning vertically through the fifth lumbar and the first sacral vertebra on either side of the midsagittal plane. Photographs of the cut surfaces were computationally enlarged and mapped for vertical and transverse trabecular numbers and surface areas using the software Image J. All parameters including the trabecular density were computed for anterior, middle, and posterior segments of each of the vertebral elements.
  
  
  RESULTS
  The anterior and the posterior segments showed greater number of trabeculae across all LSTV subtypes in both the terminal lumbar and first sacral vertebrae in comparison with the middle segment. L5 exhibited greater number of vertical trabeculae, whereas the first sacral segments demonstrated greater number and densities of transverse trabeculae. Transition-associated vertebrae showed overall reduced number of the lumbar trabeculae but relatively compact sacral posterior segments with greater number of horizontal trabeculae.
  
  
  CONCLUSIONS
  Findings suggest that some of these variations have overall reduced number of trabeculae across lumbo-sacral vertebrae in LSTV. Screw placements and subsequent pullouts in LSTV may be reviewed in light of different trabecular patterns as reported in this study.
authors.affiliation: Department of Anatomy, SRM Medical College, Kattankulathur, Kanchipuram District, Tamil Nadu 603203, India. mahatonk@yahoo.co.in
authors.forename: Niladri Kumar
authors.initials: NK
authors.lastname: Mahato
mesh_terms: D015519:Bone Density / Q000502:physiology*; D001863:Bone Screws; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D008161:Lumbosacral Region / Q000502:physiology*; D012447:Sacrum / Q000502:physiology*
keywords: Load transmission; Low back pain; Trabeculae