[Use of cartilage transplants in middle ear surgery. A histologic long-term study of cartilage implants]

30 autogenic and allogenic (homologous) cartilage grafts removed from the middle ear after an average time of 9 years and a maximal time of 25 years were studied by light microscopy. Half of the grafts showed signs of cellular vitality. Degeneration and avital cells are predominant in all grafts. Persisting residual vitality does not influence resorption and matrix necrosis in other areas of the graft. More than two thirds show structural changes by cellular resorption, infraction and vascularisation. These changes appear mainly independent of the time elapsed after transplantation. 5 grafts show bone new formation. Circumscript necrosis of the cartilage matrix was seen in 12 grafts. The study indicates that in comparison to ossicles or alloplastic material cartilage is less advisable to be used for the reconstruction of the ossicular chain due to the unpredictable degradation and loss of form stability.