Transcranial direct current stimulation combined with rehabilitation training for chronic spinal pain: a systematic review and Meta-analysis

Objective To evaluate the incremental clinical effects and safety of active transcranial direct current stimulation (tDCS) added to rehabilitation in adults with chronic spinal pain. Methods PubMed, Web of Science Core Collection, CENTRAL, SPORTDiscus via EBSCOhost, and CNKI were searched from inception to 4 July 2026. Randomized trials evaluating active tDCS combined with rehabilitation were eligible. Primary meta-analyses were restricted to active versus sham tDCS delivered with the same or closely matched rehabilitation programme and used immediate post-intervention endpoint data. Hedges’ g was pooled using restricted maximum-likelihood random-effects models with Knapp–Hartung inference. Risk of bias was assessed using RoB 2, and certainty of evidence was evaluated using GRADE. Results Ten independent randomized trials involving 372 participants across all study arms were included. Four trials involving 167 participants contributed to the pain-intensity meta-analysis. The pooled effect favoured active tDCS combined with rehabilitation over sham tDCS combined with matched rehabilitation (Hedges’ g = 0.59, 95% CI 0.11–1.06; p = 0.030; I 2 = 7.3%), although certainty was low. Five trials involving 189 participants contributed to the disability meta-analysis, for which the pooled effect was inconclusive and substantially heterogeneous (g = 0.37, 95% CI − 0.51–1.26; p = 0.305; I 2 = 77.3%; very-low-certainty evidence). Quality of life, psychological, motor, postural, and neurophysiological outcomes showed no consistent additional benefit. Six trials reported adverse-event or tolerability data. No serious adverse events were reported, but monitoring was incomplete and one participant withdrew because of contact dermatitis. Conclusion Low-certainty evidence suggests that active tDCS added to matched rehabilitation may provide an immediate reduction in pain intensity in adults with chronic spinal pain. Effects on disability and other clinical outcomes remain uncertain, and the available evidence is insufficient to establish safety or exclude uncommon harms. tDCS should therefore remain an investigational adjunct pending adequately powered sham-controlled trials with matched rehabilitation, longer follow-up, and standardized adverse-event monitoring. Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420261441551 , CRD420261441551.