*6.6. Conclusion for Conduits*

Axon regeneration through conduits can be increased compared to that through empty collagen conduits by modifying their composition, architectures, and the factors/cells they contain. However, no conduit tested is as effective as allografts in inducing axon regeneration across both short and long gaps [55,68,204] under nerve injury conditions that are common clinically, such as a long gap in older patients that must be repaired at a long time post-trauma. An additional challenge is that the conduits that are most effective in animal models cannot be used clinically. Therefore, collagen conduits are the most commonly used clinically.
