title: Spinal segment range of motion as a function of in vitro test conditions: effects of exposure period, accumulated cycles, angular-deformation rate, and moisture condition.
abstract: The purpose of this study was to thoroughly evaluate the relationship of possible mechanical and environmental conditions in the testing of spinal joint segments, including ambient-temperature exposure, accumulated test cycles, angular-deformation rate, and moisture condition on the motion characteristics of joints, with the example of isolated spinal segments.
  
  
  
  In one test, controlled loading was applied to six motion segments every 8 hours in each of the primary anatomical directions while moisture was held constant. In a second test, 18 specimens were divided equally into moisture-static, air-exposed, and slowly irrigated groups and loaded to 500 cycles. In a third test, a similar sample was tested over a range of angular-deformation rates (0.6-5.1 degrees/second).
  
  
  
  Range of motion (ROM) increased steadily with ambient-temperature exposure time, resulting in a 10% change at about 20 hours but was most stable in the moisture-static group over both accumulated load cycles and loading rate changes.
  
  
  
  The most critical factor for functional testing of spinal segments appears to be length of exposure.
authors.affiliation: Department Unfallchirurgische Forschung und Biomechanik, Universität Ulm, Germany. wilke@sirius.medizin.uni-ulm.de
authors.forename: H J
authors.initials: HJ
authors.lastname: Wilke
authors.forename: B
authors.initials: B
authors.lastname: Jungkunz
authors.forename: K
authors.initials: K
authors.lastname: Wenger
authors.forename: L E
authors.initials: LE
authors.lastname: Claes
mesh_terms: D000818:Animals; D006813:Humidity; D008159:Lumbar Vertebrae / Q000502:physiology*; D008953:Models, Anatomic; D018583:Pliability; D011597:Psychomotor Performance / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D012756:Sheep; D013116:Spinal Cord / Q000502:physiology; D013314:Stress, Mechanical; D013552:Swine; D013696:Temperature; D013997:Time Factors; D016474:Weight-Bearing / Q000502:physiology