Nontubulation Repair of Peripheral Nerve Gap Using Heparin/Alginate Gel Combined with b-FGF

All types of artificial nerve graft previously developed have a tubular structure. This tubular structure prevents fibroblasts with a high proliferative ability and surrounding fibrous tissue from entering the tube and secures the route of axonal elongation.1,2 However, we initiated a study aiming to elongate the axon from the proximal to distal stump of the gapped nerve using gel without a tubular structure and developed a alginate gel cross-linked with covalent bonds sterilized by cobalt 60 γ-radiation.3,4 Restorations of the gap in cat sciatic nerve were obtained by using tubular or nontubular material consisting mainly of the alginate gel.5 In addition, a heparin/alginate gel consisting of heparin and alginate covalently cross-linked with ethylenediamine was developed, which allowed the controlled release of b-FGF as a heparin-binding growth factor.6 Based on these results, we used the controlled-release heparin/alginate gel combined with b-FGF as an artificial nerve graft in patients with digital nerve injury with the approval of the Ethical Committee of Kitano Hospital.