title: Effects of traction on structural properties of degenerated disc using an in vivo rat-tail model.
abstract: METHODS
  An in vivo rat-tail model was adopted to study the structural changes of degenerated intervertebral disc after different traction protocols.
  
  
  OBJECTIVE
  To investigate the effects of traction with different modes and magnitudes on disc with simulated degeneration.
  
  
  BACKGROUND
  Traction has been commonly used in clinical practice for treating low back pain. Its effects on disc with degeneration have not been fully investigated.
  
  
  METHODS
  Forty-seven mature rats were used. Continuous static compression of 11 N was applied to the rat caudal 8-9 disc for 2 weeks to simulate disc degeneration. Tractions with different modes (static or intermittent) and magnitudes (1.4 N or 4.2 N) were applied to the degenerated disc for 3 weeks. The disc height was quantified in vivo on days 4, 18, and 39. The treated discs were then harvested for morphologic analysis.
  
  
  RESULTS
  Significant decrease in disc height with degenerative morphologic changes was observed after the application of the static compression. The changes in disc height after the application of traction were found to be magnitude dependent. Continuous decrease in disc height was observed after 4.2-N traction, whereas the disc height maintained after traction of 1.4 N. However, no obvious morphologic change was found in comparison with the degenerated discs without traction.
  
  
  CONCLUSIONS
  Although traction was not demonstrated to have restored disc with degeneration, traction with relatively low magnitude was found to have significant beneficial effect in maintaining disc height of degenerated disc, and it might be a potential intervention to slow down the process of degeneration. Future studies of the effects of low-magnitude traction on degenerated disc are recommended.
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China.
authors.forename: Alon
authors.initials: A
authors.lastname: Lai
authors.forename: Daniel H K
authors.initials: DH
authors.lastname: Chow
mesh_terms: D000818:Animals; D019245:Compressive Strength; D004195:Disease Models, Animal; D007403:Intervertebral Disc / Q000473:pathology / Q000503:physiopathology*; D055959:Intervertebral Disc Degeneration / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013623:Tail / Q000503:physiopathology*; D013997:Time Factors; D014143:Traction / Q000379:methods*; D016896:Treatment Outcome