title: A continuous pure moment loading apparatus for biomechanical testing of multi-segment spine specimens.
abstract: An apparatus is described that enables the application of continuous pure moment loads to multi-segment spine specimens. This loading apparatus allows continuous cycling of the spine between specified flexion and extension (or right and left lateral bending) maximum load endpoints. Using a six-degree-of-freedom load cell and three-dimensional optoelectronic stereophotogrammetry, characteristic displacement versus load hysteresis curves can be generated and analyzed for different spinal constructs of interest. Unlike quasi-static loading, the use of continuous loading permits the analysis of the spine's behaviour within the neutral zone. This information is of particular clinical significance given that the instability of a spinal segment is related to its flexibility within the neutral zone. Representative curves for the porcine lumbar spine in flexion-extension and lateral bending are presented to illustrate the capabilities of this system.
authors.affiliation: Department of Surgery, Division of Orthopaedics and Clinical Mechanics Group, Queen's University, Kingston, Ontario, Canada. 3jtl@qlink.queensu.ca
authors.forename: J T
authors.initials: JT
authors.lastname: Lysack
authors.forename: J P
authors.initials: JP
authors.lastname: Dickey
authors.forename: G A
authors.initials: GA
authors.lastname: Dumas
authors.forename: D
authors.initials: D
authors.lastname: Yen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001703:Biophysics / Q000295:instrumentation; D004581:Electronics; D004867:Equipment Design; D007259:Infrared Rays; D007593:Joint Instability / Q000503:physiopathology; D017846:Longitudinal Ligaments / Q000502:physiology; D008159:Lumbar Vertebrae / Q000502:physiology*; D009068:Movement; D055095:Optics and Photonics; D010780:Photogrammetry; D018583:Pliability; D012815:Signal Processing, Computer-Assisted; D013314:Stress, Mechanical; D013552:Swine; D016474:Weight-Bearing / Q000502:physiology*