The effects of freezing or freeze-drying on the biomechanical properties of the canine intervertebral disc.

The transplantation of spinal allografts to correct defects that include disc, body, or segments of both is currently under experimental investigation. A method of graft preservation that will least compromise the biomechanical integrity of the bodies or discs is required. Using a five-mode biomechanical analysis, the authors compared the change in stiffness of ten preserved canine spines. The freeze-dried specimens lost a significantly greater amount of stiffness in compression, flexion, extension, and torsion than did the frozen specimens. Therefore, from a biomechanical viewpoint, deep-freezing is superior to freeze-drying for spinal allograft preservation.