Scaffold for facial nerve reconstruction

Abstract The facial nerve, which is the seventh cranial nerve, mediates facial expression and a variety of other functions critical for communication and normal facial movement. Facial nerve lesions remove motor control of facial muscles, resulting in palsy. Strategies used to aid peripheral nerve regeneration include neurorrhaphy, nerve transfers, and muscle transfers, with direct suture and autograft being the current gold standard. These treatments on larger nerve gaps often result in excessive tension and scarring, leading to poor functional recovery. Facial nerve scaffolds have emerged as a promising solution to this problem. The scaffolds implement hydrogels, oriented bridges and channels, nanofibers, and detailed micropatterns to aid in axonal regeneration. Engineered conduits guide proper neurite growth, prevent invasion of surrounding tissue, and create microenvironments that enhance regeneration with biological and chemical cues. The synthetic and biological polymers, used to manufacture scaffolds and their design, heavily dictate resulting scaffold biocompatibility and mechanical properties. An effective scaffold design with added glial and stem cells, as well as delivery systems for neurotrophic factor and cytokine release, further improves regeneration potential. Research surrounding bioelectrical interfaces is a promising frontier and adds another dynamic element to conduit design. Combinations of these approaches inch closer to producing clinically translatable results and better patient outcomes.