1. 2021;24;135-143Effectiveness of Dry Needling with Percutaneous Electrical Nerve Stimulation of High Frequency Versus Low Frequency in Patients with Myofascial Neck Pain
   Randomized Trial
   Hector Beltran Alacreu, PhD, Jose Vicente Leon Hernandez, PhD, Cesar Calvo-Lobo, PhD, Josue Fernandez-Carnero, PhD, and Aitor Martin-Pinado Zugasti, PhD.

BACKGROUND: Percutaneous nerve electrical stimulation is a novel treatment modality for the management of acute and chronic myofascial pain syndrome.

OBJECTIVES: To compare the effectiveness of dry needling combined with percutaneous electrical nerve stimulation  of low frequency versus high frequency, in patients with chronic myofascial neck pain.

STUDY DESIGN: Randomized, single-blind trial.

SETTING: Laboratory in an academic institution.

METHODS: A total of 40 volunteer patients with chronic neck pain were randomly divided into 2 groups. All patients initially received deep dry needling in a myofascial trigger point of the upper trapezius. Then, one group received high frequency percutaneous electrical nerve stimulation while the other group received low frequency percutaneous electrical nerve stimulation. The primary outcomes were the visual analog scale  and the pressure pain threshold, while Neck Disability Index and Kinesiophobia were secondary outcomes.

RESULTS: We detected significant improvements in the visual analog scale score in both groups without differences between them. We did not observe significantly different statistics in either group during the evaluation of data on pressure pain threshold.

LIMITATIONS: Limitations of the study include (1) heterogeneity of the sample in relation to gender, with more women, (2) the small sample size (40 patients), (3) the absence of placebo group, and (4) the fact that the treatment is focused exclusively on the upper trapezium myofascial trigger point. .

CONCLUSIONS: Low and high frequency percutaneous electrical nerve stimulation combined with deep dry needling showed similar effects, since no differences between groups were observed on any of the outcome measures. High and low frequency of percutaneous electrical nerve stimulation generates changes on pain intensity and disability, but not on pressure pain threshold or fear of movement.

KEY WORDS: Neck pain, disability, trigger points, TENS, PENS, dry needling, physiotherapy, neck muscles