[A biochemical analysis of experimental chemonucleolysis].
We have studied the mechanical properties of enzyme-injected canine intervertebral discs by quasi-static compression tests, dynamic vibration tests and histology at 2 weeks (short-period group) and within 6 months (long-period group) after enzyme injection. The findings of each group were compared with those of normal discs as a control. The results were as follows; The quasi-static tests: In the short-period group, normalized stiffness of the discs was reduced significantly and the normalized creep rate was increased. The intradiscal pressures produced by external loading in short-period discs were almost half those of the control. In the long-period group such values tended to recover partially. The dynamic tests: In the short-period group, both elasticity and viscosity were reduced, while in the long-period group elasticity recovered but viscosity did not. These findings suggest that the shock-absorbing ability of enzyme-injected discs does not recover.
Koyanagi
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Department of Orthopedic Surgery, School of Medicine, Keio University, Tokyo, Japan.
D000818:Animals; D001696:Biomechanical Phenomena; D002917:Chymopapain / Q000627:therapeutic use; D004285:Dogs; D004548:Elasticity; D007403:Intervertebral Disc / Q000473:pathology / Q000503:physiopathology*; D007404:Intervertebral Disc Chemolysis; D007405:Intervertebral Disc Displacement / Q000188:drug therapy; D003012:Microbial Collagenase / Q000627:therapeutic use; D014783:Viscosity
D002917:Chymopapain; D003012:Microbial Collagenase