Efficacy of percutaneous needle electrolysis versus dry needling in musculoskeletal pain: A systematic review and meta-analysis

This systematic review and meta-analysis investigated the efficacy of percutaneous needle electrolysis (PNE) compared to dry needling (DN) in the treatment of musculoskeletal pain. PNE consists of the application of continuous galvanic current through a needle that acts as a negative electrode, ultrasound-guided to the target tissue, creating a controlled non-thermal electrolytic reaction that facilitates phagocytosis and tissue regeneration. Dry needling, in turn, is an established technique that uses needles to treat myofascial trigger points through mechanical and neurological effects. The researchers performed a comprehensive search across multiple databases (PubMed, PEDro, Cochrane, SCOPUS, and Google Scholar) following PICOS and PRISMA protocols.

Only randomized clinical trials directly comparing PNE and DN for musculoskeletal pain were included, using standardized pain scales (VAS or NPRS). Six studies met the inclusion criteria, totaling 252 participants with heterogeneous conditions including supraspinatus and patellar tendinopathies, lateral epicondylalgia, temporomandibular pain, plantar pain, and patellofemoral pain syndrome. The methodological quality of the studies was assessed using the PEDro scale and the Cochrane risk of bias tool. The meta-analysis revealed that PNE showed statistically significant superiority over DN for overall pain reduction, with a mean difference of -0.74 points (95% CI, -1.34 to -0.14) and a small standardized effect size (SMD = -0.42).

However, when analyzed by specific time periods (short, medium, and long term), the results did not reach statistical significance. Heterogeneity across studies was substantial (I² = 76%), attributed to the different conditions treated, varied protocols, and distinct electrical current parameters. The GRADE assessment indicated moderate-quality evidence due to heterogeneity and limited sample size. Clinically, the observed difference was below the established minimum clinically important threshold of 1 point on the pain scale, calling into question the practical relevance of the findings.

Only three studies reported adverse events, with only one hematoma observed, suggesting that both techniques are safe. PNE demonstrated a slightly superior analgesic effect, possibly due to the controlled anti-inflammatory effect of galvanic current, activation of phagocytosis, and modulation of the autonomic nervous system. The studies showed great variability in PNE treatment parameters (intensity from 350 μA to 660 mA, duration from 3 seconds to 1.2 minutes). Limitations include a small number of studies, significant methodological heterogeneity, different populations and conditions studied, and the fact that most protocols combined interventions with other complementary therapies.

The authors conclude that, although PNE showed marginal statistical advantage, the difference was not clinically significant, not allowing recommendation of PNE over DN. Future high-quality studies are needed to establish optimal PNE protocols and determine subgroups of patients who may benefit most from this intervention, especially considering that the technique was originally developed for chronic tendinopathies.