title: Angle of insertion and confirmation of angles measured after in vitro implantation during laminar vertebral stabilization in vertebral columns obtained from canine cadavers.
abstract: OBJECTIVE
  To determine angles of insertion for laminar vertebral fixation of L1 and L2 by use of a locking plate in dogs and to confirm screw placement by use of computed tomography (CT).
  
  
  METHODS
  Vertebral specimens harvested from 8 canine cadavers.
  
  
  METHODS
  The point of insertion and minimum and maximum insertion angles for laminar and facet screws for laminar vertebral stabilization were determined by use of CT. A precontoured locking plate was then placed by use of 1 locking screw in the lamina of each lumbar vertebra and 1 nonlocking screw in the facet joint. The position and angle of the screws were examined by use of CT, and penetration into the vertebral canal was recorded.
  
  
  RESULTS
  Mean ± SD insertion angles for L1 and L2 were 18 ± 4° and 21 ± 5° toward the vertebral canal and 11 ± 4.4° and 10 ± 3° in a dorsal direction, respectively. Insertion angles for the facet joint were between 24 ± 4° ventrally and 12 ± 2° dorsally. Insertion of the screw did not penetrate the vertebral canal for 23 of 24 (96%) screws. For 23 of 24 inserted screws, the previously determined angle was maintained and purchase of bone and cortices was satisfactory.
  
  
  CONCLUSIONS
  Placement of laminar and facet screws in canine vertebrae was possible and can be performed safely if angles of insertion determined pre-operatively via CT are maintained.
authors: Department of Small Animal Surgery, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland. sknell@vetclinics.uzh.ch
authors: Sebastian C
authors: SC
authors: Knell
authors: Patrick
authors: P
authors: Kircher
authors: Matthias
authors: M
authors: Dennler
authors: Pierre M
authors: PM
authors: Montavon
authors: Katja
authors: K
authors: Voss
authors: Karin
authors: K
authors: Hurter
mesh_terms: D000818:Animals; D001863:Bone Screws; D002102:Cadaver; D004285:Dogs / Q000293:injuries / Q000601:surgery*; D005592:Fracture Fixation / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D013115:Spinal Canal / Q000000981:diagnostic imaging; D013124:Spinal Injuries / Q000000981:diagnostic imaging / Q000601:surgery / Q000662:veterinary*; D014057:Tomography, X-Ray Computed / Q000662:veterinary; D021801:Zygapophyseal Joint / Q000601:surgery