WOUND-HEALING OF CARTILAGE STRUCTURES IN THE HEAD AND NECK REGION

This study was performed to determine the various processes involved i n the behaviour of hyaline cartilage during the wound healing period a fter trauma or surgery of vulnerable structures like the nasal septal cartilage and the cricoid. The results of different procedures (perpen dicular and parallel to the cartilage surface) in young and young-adul t animals were analyzed: septal incision at different locations (young -old), cricoid split (young-old), suturing cartilage, closing defects with autologous cartilage (young), biomaterials (young) and newly engi neered cartilage in 4- and 24-week-old rabbits (series of ten animals) . Cartilage of the young rabbit and child have similar hyaline cartila ge with a varying distribution in thickness. Thinner areas are more su sceptible to malformations. Incisions through younger cartilage give r ise to some new cartilage formation covered by a new layer of perichon drium; through older, differentiated cartilage the incision causes sup erficial but permanent necrosis. Edges of cut cartilage mostly do heal by formation of fibrous junctions. This forms a weak spot, sensitive to deviations. The same fate goes for the healing between the autologo us graft and the surrounding pre-existent cartilage. Trauma parallel t o the surface, leads to inconsistent quantity of neocartilage. With ag eing the wound healing and regenerative capacities decrease. In genera l, biomaterials are less accepted by the surrounding tissues and would impede further growth. Only newly engineered, and thus less different iated (younger) cartilage of hyaline nature, appeared to be well accep ted at the interface with the edges of a cartilage defect. There are i ndications that the release of growth factors might play a role in car tilage wound healing. In the child as well as the adult, wound healing of hyaline cartilage structures is incomplete, and surgery remains 'e xperimental' surgery. The clinical implications of gradual loss of the regenerative capacity of hyaline cartilage should be further investig ated. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.