Peripheral nerves have complex and precise structures that differ from other types of tissues and intrinsic regeneration abilities after injury. Spontaneous recovery is possible for neuropraxia and axonotmesis, while surgical treatment is required for neurotmesis. It remains a challenge
to repair nerve gaps, a series of severe neurotmesis. It seems that 3 cm is the upper limit distance for primate peripheral nerves to regenerate spontaneously. Nerve autografts are the gold standard treatment for bridging nerve gaps. In the present review, current biomaterials for repairing
gaps after peripheral nerve injury are briefly summarized. Moreover, the microstructure of the peripheral nerve, classifications of peripheral nerve injury, and the Wallerian degeneration are reviewed in the biological view and clinical practice. The failure of nerve regeneration in nerve
conduits bridging longer than 3 cm gaps may be contributing to the insufficient vascularization of nerve conduit materials. Future researchers could focus on advanced biomaterials that promoting the angiogenesis of nerve conduits.
Intracellular phospholipase A2 group IVA and group VIA play important roles in Wallerian degeneration and axon regeneration after peripheral nerve injury
