title: Biomechanical assessment of the effects of decompressive surgery in non-chondrodystrophic and chondrodystrophic canine multisegmented lumbar spines.
abstract: OBJECTIVE
  Dogs are often used as an animal model in spinal research, but consideration should be given to the breed used as chondrodystrophic (CD) dog breeds always develop IVD degeneration at an early age, whereas non-chondrodystrophic (NCD) dog breeds may develop IVD degeneration, but only later in life. The aim of this study was to provide a mechanical characterization of the NCD [non-degenerated intervertebral discs (IVDs), rich in notochordal cells] and CD (degenerated IVDs, rich in chondrocyte-like cells) canine spine before and after decompressive surgery (nucleotomy).
  
  
  METHODS
  The biomechanical properties of multisegmented lumbar spine specimens (T13-L5 and L5-Cd1) from 2-year-old NCD dogs (healthy) and CD dogs (early degeneration) were investigated in flexion/extension (FE), lateral bending (LB), and axial rotation (AR), in the native state and after nucleotomy of L2-L3 or dorsal laminectomy and nucleotomy of L7-S1. The range of motion (ROM), neutral zone (NZ), and NZ stiffness (NZS) of L1-L2, L2-L3, L6-L7, and L7-S1 were calculated.
  
  
  RESULTS
  In native spines in both dog groups, the greatest mobility in FE was found at L7-S1, and the greatest mobility in LB at L2-L3. Surgery significantly increased the ROM and NZ, and significantly decreased the NZS in FE, LB, and AR in both breed groups. However, surgery at L2-L3 resulted in a significantly larger increase in NZ and decrease in NZS in the CD spines compared with the NCD spines, whereas surgery at L7-S1 induced a significantly larger increase in ROM and decrease in NZS in the NCD spines compared with the CD spines.
  
  
  CONCLUSIONS
  Spinal biomechanics significantly differ between NCD and CD dogs and researchers should consider this aspect when using the dog as a model for spinal research.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, PO Box 80.154, 3508 TD, Utrecht, The Netherlands. L.A.Smolders@uu.nl
authors.forename: Lucas A
authors.initials: LA
authors.lastname: Smolders
authors.forename: Idsart
authors.initials: I
authors.lastname: Kingma
authors.forename: Niklas
authors.initials: N
authors.lastname: Bergknut
authors.forename: Albert J
authors.initials: AJ
authors.lastname: van der Veen
authors.forename: Wouter J A
authors.initials: WJ
authors.lastname: Dhert
authors.forename: Herman A W
authors.initials: HA
authors.lastname: Hazewinkel
authors.forename: Jaap H
authors.initials: JH
authors.lastname: van Dieën
authors.forename: Björn P
authors.initials: BP
authors.lastname: Meij
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D019299:Decompression, Surgical; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D055959:Intervertebral Disc Degeneration / Q000503:physiopathology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000502:physiology / Q000601:surgery*