title: Biomechanical behavior of a biomimetic artificial intervertebral disc.
abstract: METHODS
  The biomechanical behavior of a biomimetic artificial intervertebral disc (AID) was characterized in vitro in axial compression and compared with natural disc behavior.
  
  
  OBJECTIVE
  To evaluate the strength and durability of a novel biomimetic AID and to demonstrate whether its axial deformation behavior is similar to that of a natural disc.
  
  
  BACKGROUND
  Current clinically used AIDs have reasonable success rates. However, because of their nonphysiological design, spinal mechanics are altered. To avoid long-term complications, a novel biomimetic AID, with a nucleus-annulus structure and osmotic swelling properties has been developed.
  
  
  METHODS
  Eighteen AIDs in total were tested in axial compression. Six were loaded monotonically to determine strength. Six were tested in fatigue (600-6000 N). Another 6 were used to characterize the axial creep and dynamic behavior (0.01-10 Hz). Creep and dynamic response were also determined for 4 AIDs after fatigue loading.
  
  
  RESULTS
  The AIDs remained intact up to 15 kN and 10 million cycles. The creep and dynamic behavior were similar to the natural disc behavior, except for hysteresis, which was 20% to 30% higher. After fatigue, creep decreased from 4% to 1%, stiffness increased 2-fold, and hysteresis was reduced to that for a normal disc.
  
  
  CONCLUSIONS
  A strong and durable AID design was introduced. Compared with current clinical articulating AIDs, this biomimetic AID introduces the natural disc annulus-nucleus structure, resulting in axial behavior closer to that of the natural disc.
authors.affiliation: Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
authors.forename: Peter R
authors.initials: PR
authors.lastname: van den Broek
authors.forename: Jacques M
authors.initials: JM
authors.lastname: Huyghe
authors.forename: Keita
authors.initials: K
authors.lastname: Ito
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology*; D019245:Compressive Strength / Q000502:physiology*; D006801:Humans; D007403:Intervertebral Disc; D008159:Lumbar Vertebrae / Q000502:physiology; D019736:Prostheses and Implants; D016474:Weight-Bearing / Q000502:physiology