Effects of noninvasive neuromodulation in the treatment of chronic pelvic pain: a scope review

Abstract Background The management of chronic pelvic pain (CPP) requires multimodal approaches, combining pharmacological therapies, neuromodulation, and cognitive strategies. Noninvasive neuromodulation techniques such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are promising and safe conservative treatment options. They act by modulating cortical excitability, relieving pain, and influencing neuroplasticity and pain perception. Objective To map the existing literature on tDCS and TMS resources, as well as dosimetry, protocols used, and clinical results. Methods The databases included were: PubMed, Embase, The Cochrane Library, Web of Science, Scopus, and LILACS. Gray literature sources included: Google Scholar, Open Grey, and ProQuest. Studies that used tDCS and/or TMS in individuals with CPP were included. There were no restrictions on study design and/or type. There were no restrictions on publication period or language. Duplicates were removed using EndNote and Rayyan QCRI reference managers; remaining records were screened in Rayyan. Two independent reviewers read the titles and abstracts (Phase 1) and read the full studies (Phase 2), and any disagreements were resolved by consensus. Results Twenty-one studies were included in this scoping review. These included four randomized clinical trials, three pilot studies, nine clinical trial protocols, three case studies, and two review studies. Conclusion This scoping review identified 21 studies examining noninvasive neuromodulation for chronic pelvic pain. While included studies generally followed established safety guidelines, substantial methodological heterogeneity exists in dosimetry, protocols, and outcome measurement. Most evidence (57%) consists of study protocols (n=9), pilot studies (n=3), and case reports (n=3), with only 4 completed randomized controlled trials. Preliminary evidence suggests tDCS may reduce pain intensity, but high-quality, large-scale clinical trials with standardized protocols are needed to establish efficacy and optimal treatment parameters.