CRYOPRESERVATION OF PIG TRACHEA

A method of graft preservation is essential if tracheal allografts are to become an option in reconstructing long, circumferential defects. This study evaluated the effect of cryopreservation on tracheal grafts . Eight 6-ring tracheal segments obtained from sacrificed pigs were cr yopreserved for 2 months at - 196-degrees-C by a standard low-freezing technique. Once thawed, 5 were examined histologically (group A) and 3 were wrapped with omentum and then implanted in the peritoneum of a donor pig (group B). Grafts were examined 1 month later. In 10 piglets (group C), a 4-ring segment of cervical trachea was removed and the d efect closed by primary anastomosis. The graft was cryopreserved for 7 days, thawed, then reimplanted by dividing the thoracic trachea and i nterposing the cryopreserved trachea wrapped with omentum. Three pigle ts developed respiratory distress and were killed after 7 to 20 days; the remaining 7 were killed after 1 month. The grafts were rigid in gr oups A and B. Chondrocytes were present in group A, but in group B gho st cells were noted. Group C grafts were less rigid than the normal tr achea although they did not collapse. Microscopically, cartilage had b een replaced by fibrous tissue. Cryopreservation failed to maintain th e viability of chondrocytes. However, the resulting fibrous trachea ma y prove to be a satisfactory alternative for replacement of longitudin al defects such as those created by tracheoplasty to treat congenital tracheal stenosis.