Challenges to nerve regeneration

Peripheral nerve injuries can result from mechanical, thermal, chemical, co ngenital, or pathological etiologies. Failure to restore these damaged nerv es can lead to the loss of muscle function, impaired sensation, and painful neuropathies. Current surgical strategies for the repair of critical nerve s involve the transfer of normal donor nerve from an uninjured body locatio n. However, these "gold standard" methods for tissue restoration frequently are limited by tissue availability, risk of disease spread, secondary defo rmities, and potential differences in tissue structure and size. One possib le alternative to autogenous tissue replacement is the development of engin eered constructs to replace those elements necessary for axonal proliferati on, including a scaffold, support cells, induction factors, and extracellul ar matrices. Despite advances and contributions in the field of tissue engi neering, results to date with nerve conduits have failed to equal the nerve regeneration achieved with autogenous grafts for large distances. We revie w the current challenges to tissue-engineered constructs. Each of the four components is reviewed and approaches are outlined. Semin. Surg. Oncol. 19: 312-318, 2000. (C) 2000 Wiley-Liss, Inc.