Effects of freezing on the biomechanics of the intervertebral disc

Storage of anatomic specimens is possible only if there is a reliable metho d for preservation of the tissues. The establishment of such a procedure is thus of twofold importance: clinical (transplantation of segments of the v ertebral column) and experimental (research and teaching programs). Simple freezing at -18 degrees C is the simplest and least expensive method for st oring spinal specimens compared to other modes of storage such as cryo-pres ervation and lyophilization. Does this mode of storage affect the biomechan ics of frozen anatomic specimens, in particular those of the intervertebral disc? This experiment dealt with the comparative biomechanical analysis be fore and after three months of freezing of 19 segments of the sheep vertebr al column (4 functional C4-C5 units, 3 C7-T1 units, 6 T13-L1 units and 6 L5 -L67 units). The results showed that there was no significant difference (r isk of error 5%) between frozen and fresh segments of vertebral column in t erms of amplitude and rigidity, except for the C7-T12 segment where the con ditions of validity of the statistical tests were not met. The results of t his experiment allowed us to validate a biomechanical model to assay the ef fects of freezing.