Advances in Stem Cell Applications for Nerve Injury: A Meta-Analysis of Recent Experimental Models and Outcomes

Objective. This meta-analysis aimed to assess the effectiveness of stem cell-seeded conduits compared with autografts and empty conduits in preclinical models of peripheral nerve repair. Methods. A systematic review and meta-analysis was conducted of in vivo preclinical studies published between 2013 and 2024. Endpoints included muscle mass ratio, sciatic function index (SFI), nerve conduction velocity (NCV), compound muscle action potential (CMAP) amplitude, and nerve conduction latency. Studies were further classified by stem cell type, graft material, species, and defect length. Results. Across 30 studies, both stem cell-seeded conduits and autografts outperformed controls across functional and electrophysiological measures. Early improvements (0-3 months) in muscle mass ratio were observed with both stem cell grafts (p = 0.014) and autografts (p = 0.027). SFI improved significantly in both groups at early time points, with stem cell grafts maintaining significance beyond 3 months (p = 0.04). CMAP amplitude showed early gains for both stem cell grafts (p < 0.001) and autografts (p < 0.001), with autografts performing slightly better initially (p = 0.033). NCV improved in both groups early, with stem cell grafts maintaining significance beyond 3 months (p = 0.007). Autografts showed early improvements in latency (p = 0.048), whereas stem cell grafts trended toward benefit without reaching significance. Conclusions. These findings suggest that stem cell-seeded grafts may provide functional benefits similar to autografts in peripheral nerve repair compared with empty conduits. Clinically, this method could be valuable when autografts are unavailable or when harvesting is contraindicated.