title: Facet loads in the canine lumbar spine before and after disc alteration.
abstract: The effect of externally applied spinal loads on facet mechanics before and after facet capsulectomy and disc alteration was investigated. Four control and four chymopapain-treated specimens were tested. Facet load and resultant load location were determined in the unaltered state, after facet capsulectomy, and after discectomy using a newly developed, noninvasive measurement technique. Resultant contact load locations shifted in a predictable manner. Caudal shift in contact locations occurred with chymopapain treatment or discectomy but was variable with capsulectomy. Facet load changed with applied load magnitude and direction; no significant change was noted after intradiscal chymopapain, discectomy, or capsulectomy. The significance of the lack of force change with disc narrowing is unknown. Perhaps, observed facet degeneration results from a change in the joint motion and contact location rather than change in facet load.
authors: Department of Orthopaedic Surgery, University of Minnesota, Minneapolis.
authors: R D
authors: RD
authors: Kahmann
authors: G R
authors: GR
authors: Buttermann
authors: J L
authors: JL
authors: Lewis
authors: D S
authors: DS
authors: Bradford
mesh_terms: D000818:Animals; D002917:Chymopapain; D004285:Dogs; D007403:Intervertebral Disc / Q000502:physiology* / Q000601:surgery; D007404:Intervertebral Disc Chemolysis; D008159:Lumbar Vertebrae / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D002917:Chymopapain