Prolonged Cold-preservation of Nerve Allografts

The goal of this study was to determine the effect of varying durations of cold-preservation on the immunogenicity of nerve allografts and their subsequent ability to facilitate neuroregeneration across a short nerve gap. Allografts preserved for 1, 4, and 7 weeks were compared to untreated allografts and isografts. There was a shift from an interferon-gamma-producing cellular response (untreated allografts) to an absence of response (7-week cold-preserved allografts and isografts). There were no detectable alloantibodies by flow cytometry. Histomorphometry distal to the graft showed robust regeneration in the isograft and 7-week cold-preserved groups when compared to the untreated allograft group. Increasing duration of cold-preservation diminished the cellular immune response. This cold-preservation does not preclude subsequent nerve regeneration across a short nerve graft. Prolonged cold-preservation of nerve allograft tissue could serve as a means to produce unlimited graft material for use in peripheral nerve reconstruction.