Benefits and Harms of Electrical Neuromodulation for Chronic Pelvic Pain: A Systematic Review

CONTEXT: Patients with chronic pelvic pain (CPP) may have pain refractory to conventional pain management strategies. Neuromodulation could provide relief of pain. OBJECTIVE: To evaluate the benefits and harms of neuromodulation for CPP. EVIDENCE ACQUISITION: A comprehensive search of EMBASE, PUBMED, and SCOPUS was performed for the entire database to January 2018. Studies were selected, data were extracted, and quality was assessed by two independent reviewers. A meta-analysis was used to combine randomized controlled trials (RCTs); otherwise, a narrative analysis was used. EVIDENCE SYNTHESIS: After screening 1311 abstracts, 36 studies including eight RCTs were identified, enrolling 1099 patients. Studies covered a broad range in terms of phenotypes of CPP and methods of neuromodulation. A meta-analysis was possible for percutaneous tibial nerve stimulation and transcutaneous electrical nerve stimulation, which showed improvement in pain. Only narrative synthesis was possible for other modalities (sacral nerve stimulation, spinal cord stimulation, intravaginal electrical stimulation, and pudendal nerve stimulation) which appeared to reduce pain in patients with CPP. Treatments generally improved quality of life but with variable reporting of adverse events. Many studies showed high risks of bias and confounding. CONCLUSIONS: While electrical neuromodulation may improve symptoms in CPP, further work is needed with high-quality studies to confirm it. PATIENT SUMMARY: Neuromodulation may be useful in reducing pain and improving quality of life in patients with chronic pelvic pain, but more research is needed.