Experimental Considerations Concerning the Use of Stem Cells and Tissue Engineering for Facial Nerve Regeneration: A Systematic Review

Purpose: Peripheral nerve trauma results in functional loss in the innervated organ, and recovery without surgical intervention is rare. Many surgical techniques can be used for repair in experimental models. The authors investigated the source and delivery method of stem cells in experimental outcomes, seeking to clarify whether stem cells must be differentiated in the injured facial nerve and improve the regenerative process. Materials and Methods: The following key terms were used: nervous regeneration, nerve regeneration, facial nerve regeneration, stem cells, embryonic stem cells, fetal stem cells, adult stem cells, facial nerve, facial nerve trauma, and facial nerve traumatism. The search was restricted to experimental studies that applied stem cell therapy and tissue engineering for nerve repair. Results: Eight studies meeting the inclusion criteria were reviewed. Different sources of stem and precursor cells were explored (bone marrow mesenchymal stem cells, adipose-derived stem cells, dental pulp cells, and neural stem cells) for their potential application in the scenario of facial nerve injuries. Different material conduits (vases, collagen, and polyglycolic acid) were used as bridges. Immunochemistry and electrophysiology are the principal methods for analyzing regenerative effects. Although recent studies have shown that stem cells can act as a promising bridge for nerve repair, considerable optimization of these therapies will be required for their potential to be realized in a clinical setting. Conclusion: Based on these studies, the use of stem cells derived from different sources presents promising results related to facial nerve regeneration and produces effective functional results. The use of tubes also optimizes nerve repair, thus promoting greater myelination and axonal growth of peripheral nerves. (C) 2014 American Association of Oral and Maxillofacial Surgeons