Efficacy of Mesenchymal and Embryonic Stem Cell Therapy for the Treatment of Spinal Cord Injury: A Systematic Review and Meta-Analysis of Human Studies

Study Design: Systematic review and meta-analysis. Objectives: The objective of this study was to conduct a systematic review and meta-analysis of the literature regarding the therapeutic effect of embryonic and mesenchymal stem cells on the treatment of traumatic spinal cord injury (SCI) in humans. Primary outcome measures were overall American Spinal Injury Association (ASIA) scores, ASIA motor and sensory scores, urinary and bowel function, pain, and adverse events. Methods: Studies with human patients ages 18-80 years receiving embryonic, induced pluripotent, or mesenchymal stem cells for SCI were included. Study quality was assessed using the Cochrane risk of bias 2 tool and the Newcastle Ottawa scale for randomized and non-randomized studies, respectively. Primary outcomes were overall ASIA grade, ASIA motor scores, ASIA sensory scores, bladder and bowel function, pain, and adverse events. Results: Thirty total studies with 656 patients were included, with 43.3% of patients experiencing improvement in ASIA grade, 49.4% in motor function, and 73.6% in sensory function. Qualitative analysis of bladder and bowel outcomes suggests overall improved sensation and control. No serious adverse events were reported. The most common side effects were mild and resolved within hours to weeks without requiring additional medical treatment. Conclusions: Stem cell transplantation for SCI appears to offer moderate improvements in overall ASIA grade, motor, sensory, bladder, and bowel function, accompanied by a relatively mild and transient side effect profile. Further research, particularly high-quality, blinded, randomized controlled trials, is essential to optimize treatment protocols and achieve more consistent and improved clinical outcomes.