Epidural Spinal Cord Stimulation for Spasticity: A Systematic Review

Hypertonia resulting from central nervous system damage impairs mobility, induces pain, and diminishes quality of life, with conventional therapies having limited efficacy. This systematic review assesses the efficacy, safety, and quantitative outcomes of epidural spinal cord stimulation (eSCS) for refractory spasticity in adults, with an emphasis on prospective interventional studies that include objective measures.

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (2020) guidelines, PubMed, Embase, Scopus, and Web of Science were searched from inception to June 2025 for prospective interventional studies and studies with prospective data collection elements (randomized controlled trials, nonrandomized trials, cohorts, and case series, n ≥ 5), involving adults (≥18 years) with spasticity of any etiology that was treated with eSCS. Records (n = 2872 after duplicates were removed) were screened independently by two reviewers; nine studies (total n = 247 patients, with 176 receiving eSCS) met the inclusion criteria. Data extraction focused on spasticity reduction (eg, Modified Ashworth Scale [MAS]), functional outcomes, safety, and adverse events. Due to study heterogeneity, a descriptive synthesis was performed.

Included studies (1980-2024) predominantly involved spinal cord injury (SCI; 69%), with smaller cohorts for traumatic brain injury, stroke, and multiple sclerosis. eSCS electrode placement ranged from cervical (C3-C7) to thoracic (Th10-L1) and upper lumbar levels. Mean age was 35.6 years, and median follow-up was 12 months (range, 0.25-24 months). MAS reductions were consistent (pooled mean decrease of approximately 1.77 points; SCI subgroup mean -2.41 points from 3.65 to 1.24). Spasticity improved in most patients (reported response rates ranging from 62% to approximately 80%), with functional gains (eg, ambulation, activities of daily living, and independence) demonstrated in approximately 35% to 75% of patients. Adverse events were infrequent (<10%), mainly including hardware migration or transient autonomic dysreflexia; no deaths or irreversible deficits were reported.

Prospective evidence indicates eSCS may effectively reduce spasticity, particularly in chronic SCI, with meaningful functional benefits and favorable safety. Heterogeneity in study design, stimulation and implantation parameters, outcome measures, and follow-up timing, along with small sample sizes, limits generalizability. Therefore, larger, multicenter trials with standardized reporting are needed to optimize paradigms and to define the mechanistic role in spasticity management. We suggest a minimum data set toward homogenizing future dissemination of knowledge.