Is cellulose sponge degradable or stable as implantation material? An in vivo subcutaneous study in the rat

The long-term behaviour of cellulose sponge implants, 10 x 10 x 5 mm in siz e, and tissue reactions in and around them were examined in the subcutaneou s tissue of the rat from 1 to 60 weeks after implantation. The cellulose sp onge used was filled up with connective tissue 4 to 8 weeks after implantat ion. Histologically, moderate foreign body tissue reaction inside the impla nt, the appearance of cracks and fissures, spotty colouration, and softenin g of the pore walls were observed up to 16 weeks after implantation. Later, the foreign body reaction inside the sponge became milder, the spotty colo uration disappeared and micropores enlarged in the viscose cellulose matrix . Histomorphometrically, the cross-sectional area of the implants and the s ize of the pore wall fragments decreased, and the number of pore wall fragm ents increased significantly. The cellulose sponge used can be regarded as a slowly degradable implantation material. However, the time needed for the total disappearance of the cellulose sponge from subcutaneous tissue is lo nger than the 60 weeks. (C) 1999 Elsevier Science Ltd. All rights reserved.