Peripheral nerve damage in the extremities and face results in a debilitating loss of sensory and motor functions. Current standards of repair to treat peripheral nerve injuries include suturing nerve stumps end-to-end (across the nerve gap created by the injury) or using autologous nerve or vein grafts to bridge the gap. Problems arise with the first technique when the nerve gap created is large and suturing stumps end-to-end will produce too much tension on the nerve.  Problems also exist with using autologous grafts such as loss of feeling at the donor site, scarring caused by secondary surgeries, and pain. Therefore, in the past decade, tubulization, implanting a biologic or synthetic tube (conduit) around the nerve gap and bringing the nerve stumps into the conduit, has become a popular method to repair severed nerves. Tubulization allows factors and cells to remain in direct contact with the regenerating nerve, provides direction to axons, and protects the wound space from cells and tissues outside of the inner lumen.

     Peripheral Nerve Regeneration projects at the Kohn Lab aim to reconstruct severed nerves with critically large gaps by fabricating biodegradable, polymeric, porous conduits using tyrosine-derived polycarbonates.  These conduits provide physical and biologic guidance to regenerating nerves. Commercially available synthetic nerve conduits are limited by the size of the nerve gap they can bridge (<3 cm in humans). By imparting optimal mechanical and degradation properties as well as biological cues to the conduits, we are designing nerve guidance conduits that will help bridge longer nerve gaps and achieve improved functional recovery.