title: Computed tomographic evaluation of dynamic alteration of the canine lumbosacral intervertebral neurovascular foramina.
abstract: OBJECTIVE
  To develop a computed tomographic (CT) method to measure the volume of the lumbosacral intervertebral neurovascular foramina (IVF) in dogs, and determine the effect of the range of motion of the lumbosacral (LS) junction on this measurement in German shepherd dogs (GSDs) with degenerative lumbosacral stenosis (DLSS) compared to unaffected controls.
  
  
  METHODS
  In vivo analysis and retrospective case series.
  
  
  METHODS
  Twenty-four working Police GSDs, 12 diagnosed with DLSS and 12 unaffected by DLSS were compared to 10 Greyhounds without DLSS.
  
  
  METHODS
  Three-dimensional renderings of CT data were used to measure the lumbosacral foraminal volume of dogs positioned in dorsal recumbency with the LS junction alternately positioned in extension, neutral position, and flexion.
  
  
  RESULTS
  Volumetric analysis of the IVF was found repeatable for the extended and neutral positions (interclass correlation coefficient of 0.89 and 0.8, respectively). The mean lumbosacral IVF volume was decreased by 74% between LS flexion and extension in Greyhounds, compared to 79 and 85% reductions in GSDs unaffected and affected by DLSS, respectively. The lumbosacral IVF volume was decreased by 23% when comparing extended to neutral LS positions in Greyhounds, 29% in unaffected GSDs, and 31% in affected GSDs. IVF volumes were smaller in affected GSDs compared to unaffected GSDs (P < .05) and Greyhounds (P < .01).
  
  
  CONCLUSIONS
  Positioning the LS junction in full extension decreases the volume of the lumbosacral IVF. This dynamic narrowing was more pronounced in GSDs with signs of DLSS than in GSDs not overtly affected by DLSS.
authors.affiliation: Massey University Working Dog Centre, Massey University, Palmerston North, New Zealand.|Massey University Veterinary Teaching Hospital, Palmerston North, New Zealand.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Worth
authors.affiliation: Massey University Veterinary Teaching Hospital, Palmerston North, New Zealand.
authors.forename: Angela
authors.initials: A
authors.lastname: Hartman
authors.affiliation: Massey University Veterinary Teaching Hospital, Palmerston North, New Zealand.
authors.forename: Janis P
authors.initials: JP
authors.lastname: Bridges
authors.affiliation: Massey University Working Dog Centre, Massey University, Palmerston North, New Zealand.|Massey University Veterinary Teaching Hospital, Palmerston North, New Zealand.
authors.forename: Boyd R
authors.initials: BR
authors.lastname: Jones
authors.affiliation: Massey University Veterinary Teaching Hospital, Palmerston North, New Zealand.
authors.forename: Joe I G
authors.initials: JI
authors.lastname: Mayhew
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D004283:Dog Diseases / Q000000981:diagnostic imaging*; D004285:Dogs; D005260:Female; D007796:Laminectomy / Q000662:veterinary; D008161:Lumbosacral Region; D008297:Male; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000662:veterinary*; D014057:Tomography, X-Ray Computed / Q000662:veterinary