[Enzyme digestion of autologous cartilage transplants. New possibilities for vital cryopreservation?--Initial results].

The use of autologous cartilage grafts is one of the most common procedures in plastic surgery. Commonly used chemical preservation procedures of the cartilage for a second operation usually lead to the loss of vitality of the graft. In the past few years cryopreservation methods were used in the maintenance of the vitality of the autologous grafts, although these efforts yielded a low vitality of the grafts. It seems that the matrix of the grafts is mainly responsible for the unsuccessful cryopreservation of cartilage. In this work we tried to degrade the matrix of the cartilage grafts by partial enzymatic digestion with collagenase type II and hyaluronidase to facilitate the penetration of dimethylsulfoxide (DMSO). Cell vitality was assessed by trypan dye exclusion. We could demonstrate that it is possible to raise the permeability of the matrix by enzymatic digestion. Cryopreservation of the digested cartilage yielded a vitality of nearly 20%. Our results suggest that pretreatment of cartilage grafts with specific enzymes before preservation enable more successful vital cryopreservation.