Abstract
The collagen has been evaluated as a implantable material. In order to apply the collagen to otologic surgery, especially mastoid cavity obliteration and rebuilding of the posterior canal wall, an animal experiment was performed to study the change in the collagen implanted into the subcutaneous tissue of the rabbit. Six kinds of collagen; 1) collagen sponge irradiated with ultraviolet 2) collagen sponge tanned with glutaraldehyde (pH 5.5)3) collagen sponge tanned with glutaraldehyde (pH 7.5)4) collagen sheet irradiated with ultraviolet 5) collagen sheet tanned with glutaraldehyde (pH 5.5) 6) collagen sheet tanned with glutaraldehyde (pH 7.5), were selected. The animals were sacrified at 1, 2, 3, 4, 5, 6, 7 and 8 weeks after subcutaneous implantation. The tissues including implanted collagen were then studied microscopically by H-E stain.
The collagen sponge irradiated with ultraviolet caused slight reaction to the tissue and migration of the leukocyte and macrophage was scarce. The collagen sponge was absorbed within 3 or 4 weeks. Two kinds of sponge tanned with glutaraldehyde were not absorbed even at 8 weeks showing swelling and scattered fibrils (fragments of fiber). Leukocytes and macrophages are much more observed than in that irradiated with ultraviolet. The fibroblast and collagen formation appeared. Granulation tissues grew into the collagen sponge through the tiny holes. In summary, the collagen sponge tanned with glutaraldehyde caused moderate foreign body reaction, but good granuration formation. Thus the collagen sponge tanned with gultaraldehyde may be available for mastoid cavity obliteration.
Though cell infiltration appeared on the surface of the collagen sheet, the tissue did not grow into the sheet and the collagen sheet is still seperated from the sorrounding connective tissues. This would indicate that the collagen sheet is not suitable for rebuilding of the posterior wall of the external meatus.
