Facial nerve pathology: emerging strategies for regeneration and functional restoration

Facial nerve injuries cause significant functional impairments, affect facial expressions, speech, and overall quality of life. This article explores advances in facial nerve regeneration, encompassing both conventional and emerging therapeutic strategies. The regenerative process involves Wallerian degeneration, axonal regrowth, and target muscle reinnervation, where the distal axon degrades and the proximal axon initiates sprouting to restore connectivity. Traditional treatments, including direct nerve repair, autologous grafts, nerve transfers, and rehabilitation, vary in efficacy based on injury severity and timing. Recent innovations in biomaterials, such as collagen scaffolds, synthetic polymers, and graphene-enhanced conduits, provide structural and biochemical support for nerve repair. Electrical stimulation has shown promise in accelerating regeneration by modulating neurotrophic factor expression and guiding axonal growth. Advanced therapies, including stem cell-based interventions, exosome-mediated treatments, and intensive neurorehabilitation, offer new prospects for enhanced recovery. Despite progress, challenges remain in standardizing treatments, ensuring clinical translation, and improving long-term efficacy. This review highlights preclinical models used to assess functional outcomes, discusses bioengineered materials tailored for nerve repair, and explores future directions in processed nerve allografts, bioengineered conduits, and biochemical cues to enhance neural regeneration after facial nerve injury.