Effectiveness of transcutaneous spinal cord stimulation for lower limb rehabilitation in spinal cord injury: a systematic review.

Abstract

<h4>Background</h4>Spinal cord injury (SCI) results in devastating motor and sensory deficits below the level of injury. Transcutaneous spinal cord stimulation (tSCS) has emerged as a promising non-invasive neuromodulation technique for improving motor function in individuals with SCI. However, the effectiveness of tSCS for lower limb rehabilitation remains unclear.<h4>Objective</h4>To systematically review the effectiveness of tSCS for improving lower limb motor function, walking ability, spasticity, and functional independence in individuals with SCI.<h4>Methods</h4>We conducted a comprehensive search of PubMed, Web of Science, Embase, Scopus, CINAHL, MEDLINE, Cochrane Library, and Physiotherapy Evidence Database (PEDro) from inception to March 2025. We included randomized controlled trials (RCTs), non-randomized studies, and case series examining tSCS for lower limb rehabilitation in adults with SCI. Two reviewers independently screened studies, extracted data, and assessed risk of bias using appropriate tools (Cochrane RoB 2, ROBINS-I, JBI Critical Appraisal Checklist). We used GRADE to assess certainty of evidence.<h4>Results</h4>From 2042 identified records, 14 studies (n = 183 participants) met inclusion criteria, including 5 RCTs, 4 non-randomized studies, and 5 case series. Due to substantial clinical and methodological heterogeneity, we conducted a narrative synthesis. The single high-quality RCT (Comino-Suárez 2025) showed significant improvements in Lower Extremity Motor Score (LEMS) at follow-up (MD: 3.37, 95% CI: 0.29-6.46) and 10-meter walk test (10MWT) speed (MD: - 37.51 s, 95% CI: - 72.78 to - 2.23), but no significant effects on 6-minute walk test (6MWT) or spasticity. Most studies reported only mild adverse events (skin irritation, tingling). The certainty of evidence was very low for clinical outcomes and moderate for safety.<h4>Conclusions</h4>Current evidence suggests tSCS may improve lower limb motor function and walking speed in SCI, with a favorable safety profile. However, the evidence base has significant limitations including small sample sizes, heterogeneous protocols, and methodological concerns. Well-designed, adequately powered RCTs with standardized protocols are urgently needed.