Outcomes of transcutaneous nerve stimulation for migraine headaches: a systematic review and meta-analysis.

BACKGROUND: Implanted and transcutaneous nerve stimulators have shown promise as novel non-pharmacologic treatment for episodic and chronic migraines. The purpose of this study was to summarize the reported efficacy of transcutaneous single nerve stimulators in management of migraine frequency and severity. METHODS: A systematic review of five databases identified studies treating migraines with transcutaneous stimulation of a single nerve. Random effects model meta-analyses were conducted to establish the effect of preventive transcutaneous nerve stimulation on headache days per month and 0-10 numeric rating scale pain severity of headaches for both individuals with episodic and chronic migraines. RESULTS: Fourteen studies, which treated 995 patients, met inclusion criteria, including 7 randomized controlled trials and 7 uncontrolled clinical trials. Transcutaneous nerve stimulators reduced headache frequency in episodic migraines (2.81 fewer headache days per month, 95% CI 2.18-3.43, I2 = 21%) and chronic migraines (2.97 fewer headache days per month, 95% CI 1.66-4.28, I2 = 0%). Transcutaneous nerve stimulators reduced headache severity in episodic headaches (2.23 fewer pain scale points, 95% CI 1.64-2.81, I2 = 88%). CONCLUSIONS: Preventive use of transcutaneous nerve stimulators provided clinically significant reductions in headache frequency in individuals with chronic or episodic migraines. Individuals with episodic migraines also experienced a reduction in headache pain severity following preventive transcutaneous nerve stimulation.