The present invention teaches a micro-porous injectable, soft elastic, fully resorbable fibrin-based composition for use as a soft tissue lumen and void filler. The composition of the present application exhibits physical characteristics, such as mechanical properties, typically seen in elastomers and mechanical stability, which is superior to fibrin alone. A variety of properties of the composition of the present invention can be effectively fine-tuned and altered by adjusting type and content of the particles as well as of the plasticizer contained in the void filler composition.