Spinal cord stimulation to manage autonomic dysfunction after spinal cord injury: a systematic review

Introduction Spinal cord injury (SCI) results in severe autonomic dysfunction, across cardiovascular, bladder, bowel and sexual domains, negatively affecting quality of life. Recently, there has been growing interest in the application of spinal cord stimulation (SCS) to restore or modulate autonomic functions in people with SCI. This review systematically evaluated the evidence for spinal cord and/or root stimulation, delivered via epidural (eSCS), transcutaneous (tSCS) spinal cord stimulation, or sacral (posterior) anterior root stimulation (SARS/SPARS) – in managing autonomic dysfunction after SCI. Methods A systematic search of OVID Medline, OVID Embase, and Web of Science, was completed in September 2024. Eligible studies included adults with SCI (≥18 years old) receiving eSCS, tSCS, or SARS, reporting at least one quantitative autonomic outcome measure. Extracted data were synthesised by autonomic domain (cardiovascular, urinary, bowel, sexual), intervention type (eSCS, tSCS, or SARS) and duration of stimulation (acute vs. chronic). Results Fifty-seven articles were identified, evaluating eSCS (30 studies, n = 151), tSCS (10 studies, n = 48), and SARS (17 studies, n = 1,249) effects on cardiovascular (22 studies), bladder (23 studies), bowel (14 studies), and sexual function (13 studies). Acute application of eSCS or tSCS consistently elevated blood pressure and mitigated orthostatic hypotension, with variable effects on suppressing autonomic dysreflexia. Acute application of eSCS, tSCS or SPARS, improved bladder capacity and voiding efficiency, although not consistently and often outcomes did not reach clinically acceptable levels. eSCS, tSCS and SARS consistently reduced bowel management times. In most participants, erections could be achieved or were improved with eSCS or SARS. Chronic interventions, particularly SARS with dorsal root deafferentation, produced long term bladder and bowel improvements, whereas chronic eSCS and tSCS evidence was limited. Stimulation was most often applied to lumbosacral segments (L1–S1) at 30–60 Hz, although some studies used systematic mapping approaches. Conclusion Electrical stimulation of the spinal cord and/or nerve roots is a promising method for modulating or restoring autonomic function after SCI. However, current evidence is based on small cohort or case studies, or retrospective reporting. Larger controlled studies are recommended to establish efficacy and long-term safety, and further mechanistic investigations are required. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420250621447 , identifier PROSPERO (CRD420250621447).