The outcome of peripheral nerve repair has changed very little over the past 50 years, and clinical outcomes remain generally poor. Surgical technique has evolved to a high level of technical microsurgical proficiency, but this approach remains unable to adequately address the neurobiological barriers to the optimization of nerve regeneration. Reconstruction of complex segmental injuries, as in the brachial plexus, additionally requires a considerable length of interpositional nerve autograft, which may be unobtainable without considerable donor morbidity.
Research has therefore turned to the modulation of the repair-site environment to optimise nerve regeneration across neurorraphies, and to the creation of nerve conduits to reduce the need for nerve autograft. Tissue engineering has involved the use of growth factors to modulate neuronal and glial cell behaviour, and the creation of macro, micro and nanoscale constructs from a variety of materials in order to replace the connective tissue functions of nerve autograft. Implantation of cultured Schwann and stem cells is an area of particular development given the necessity of viable support cells to facilitate neuronal growth. These approaches are reviewed in the light of current published work.
The future of peripheral nerve repair lies in the modulation of neuronal and glial cell responses to nerve injury, and during regeneration, while taking account of the clinical requirements and practical limitations. The peripheral nervous system also provides a simpler model for nerve regeneration than the central nervous system, but with translational potential.