title: Effects of body position and clinical signs on L7-S1 intervertebral foraminal area and lumbosacral angle in dogs with lumbosacral disease as measured via computed tomography.
abstract: OBJECTIVE
  To measure effects of dog position on L7-S1 intervertebral foraminal area and lumbosacral (LS) angle by means of computed tomography (CT) and determine whether changes in values between positions are associated with clinical signs in dogs with LS disease.
  
  
  METHODS
  86 dogs examined via a positional CT protocol that included flexion and extension scans of L7-S1.
  
  
  METHODS
  Archived CT images and medical records were reviewed. Included dogs had good-quality flexion and extension CT scans of L7-S1 and no evidence of fractures, neoplasia, or previous LS surgery. One person who was unaware of CT findings recorded clinical status with regard to 3 signs of LS disease (right or left hind limb lameness and LS pain) at the time of CT evaluation. One person who was unaware of clinical findings measured L7-S1 foraminal areas and LS angles, with the aid of an image-analysis workstation and reformatted parasagittal planar CT images.
  
  
  RESULTS
  Intraobserver variation for measurements of L7-S1 foraminal area ranged from 6.4% to 6.6%. Mean foraminal area and LS angle were significantly smaller when vertebral columns were extended versus flexed. Percentage positional change in L7-S1 foraminal area or LS angle was not significantly different among dogs with versus without each clinical sign. There was a significant correlation between percentage positional change in L7-S1 foraminal area and LS angle in dogs with versus without ipsilateral hind limb lameness and LS pain.
  
  
  CONCLUSIONS
  Positional CT is a feasible technique for quantifying dynamic changes in L7-S1 intervertebral foraminal morphology in dogs with LS disease.
authors.affiliation: Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic and State University, Blacksburg, VA 24061-0442, USA.
authors.forename: Jeryl C
authors.initials: JC
authors.lastname: Jones
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Davies
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Werre
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Shackelford
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D004285:Dogs; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology; D011128:Polyradiculopathy / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary*; D011187:Posture; D012447:Sacrum / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000662:veterinary