title: Effect of dorsal laminectomy and dorsal annulectomy with partial lumbosacral discectomy on the volume of the lateral intervertebral neuroforamina in dogs when the lumbosacral junction is extended.
abstract: OBJECTIVE
  To determine the effect of dorsal annulectomy and partial discectomy on the volume of the lumbosacral lateral intervertebral neurovascular foramina (intervertebral foramina) in canine cadavers during extension of the lumbosacral junction.
  
  
  METHODS
  Ex vivo experiment.
  
  
  METHODS
  Lumbosacral specimens from 10 large breed dogs euthanatized for reasons unrelated to lumbosacral disease.
  
  
  METHODS
  The lumbosacral specimens were clamped in a wooden jig and scanned using computed tomography (CT) with the lumbosacral junction in a neutral position and loaded in extension using a tensioning device. The 3-dimensional volumes of the lumbosacral intervertebral neurovascular foramina were measured and the extent of any disc degeneration was determined from the CT data. A limited dorsal laminectomy of S1 and a dorsal LS annulectomy and partial discectomy were then performed. The lumbosacral specimens were remounted into the jig and loaded into extension at the same tension and were re-scanned. Measurements of intervertebral foraminal volume were then repeated.
  
  
  RESULTS
  The mean volume of the lumbosacral foramina (n = 20) was 381 mm3in neutral (unloaded) positioning and 137 mm3when loaded in extension. Following dorsal annulectomy, the mean volume was significantly reduced by a mean of 28% to 98 mm3(P < .01). The foraminal volume was reduced in 19/20 lumbosacral foramen, with the post-annulectomy volume ranging from 31% to 97% of the pre-annulectomy volume (3%-69% reduction).
  
  
  CONCLUSIONS
  This study suggests that a dorsal annulectomy with partial discectomy may induce further dynamic collapse of the lumbosacral articulation in the dog.
authors.affiliation: Massey University Working Dog Centre, 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, 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; D002102:Cadaver; D017586:Diskectomy / Q000662:veterinary*; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D004285:Dogs; D055959:Intervertebral Disc Degeneration / Q000601:surgery / Q000662:veterinary*; D007796:Laminectomy / Q000662:veterinary*; D008161:Lumbosacral Region; D013130:Spinal Stenosis / Q000601:surgery / Q000662:veterinary*; D014057:Tomography, X-Ray Computed / Q000662:veterinary