Effects of transcutaneous electrical nerve stimulation in complex regional pain syndrome: a systematic review.

INTRODUCTION

Complex regional pain syndrome (CRPS) causes disabling pain. Transcutaneous electrical nerve stimulation (TENS) is a treatment option. The aim of this systematic review is to evaluate the effects of TENS in patients with CRPS.

METHODS

A systematic search was conducted in PubMed, EMBASE, Cochrane CENTRAL, Web of Science, and PEDro databases up to June 2025. Randomized controlled trials (RCTs) involving patients with CRPS that evaluated the effects of TENS, regardless of parameters used, on pain intensity were considered eligible. Comparator groups could include placebo, usual care, or no intervention. Two independent reviewers extracted data, and a descriptive synthesis was performed. Risk of bias was assessed using the RoB 2 tool.

RESULTS

Of the 517 records screened, only two clinical trials met the inclusion criteria, encompassing a total of 38 participants (58% women). One study reported improvements in pain, mobility, and edema with conventional TENS compared to sham TENS. The other was a feasibility study that did not reach its recruitment target and presented only individual-level data without between-group comparisons. The assessment of the risk of bias revealed some concern about clarity of reporting of data analysis in both studies and the absence of protocol registration in one.

CONCLUSION

There was insufficient evidence to judge the efficacy of TENS for analgesic and function improvement in patients with CRPS. Further studies are needed to inform clinical decision-making.

SYSTEMATIC REVIEW: registration number CRD42024554290.