Effect of Vagus Nerve Stimulation on Trapezius Trigger Point

A Comparative Study on the Effect of Vagus Nerve Stimulation and Ischemic Compression on Trapezius Trigger Points

This randomized controlled trial aimed to evaluate the efficacy of non-invasive vagus nerve stimulation (nVNS) compared to ischemic compression (trigger point massage) and exercise in treating trigger points in the upper trapezius muscle. Ninety participants aged 18-55 with at least two trigger points were randomly assigned to three groups: nVNS, ischemic compression, or exercise (control). Interventions were administered over 10 sessions (3 times per week). Outcomes included pain intensity (Visual Analog Scale, VAS), trigger point number, pain pressure threshold (algometer), neck function (Copenhagen Neck Functional Disability Scale, KBFÖS), well-being (WHO-5 Well-Being Index), and functional mobility. The nVNS group demonstrated statistically significant improvements in all outcomes compared to the other groups (p < 0.05).

Myofascial pain syndrome (MPS) is characterized by trigger points-hyperirritable spots in skeletal muscle associated with pain, stiffness, and reduced function. The upper trapezius muscle is a common site for trigger points, contributing to neck pain and disability. Traditional treatments include ischemic compression and exercise, but non-invasive vagus nerve stimulation (nVNS) has emerged as a promising modality due to its ability to modulate pain pathways and autonomic function.

This study investigated whether nVNS is more effective than ischemic compression or exercise in reducing pain and improving function in patients with trapezius trigger points. Participants were randomized into three groups (n=30 each)

Inclusion Criteria:

• Age 18-55 years.
• Presence of at least two trigger points (active or latent) in the upper trapezius muscle, confirmed by palpation.
• Ability to provide informed consent.

Exclusion Criteria:

• History of cervical spine surgery or trauma.
• Neurological disorders (e.g., epilepsy, stroke).
• Pregnancy or breastfeeding.
• Use of pacemakers or other implanted electrical devices.
• Active infection or skin lesions at the stimulation site.
• Recent use of botulinum toxin or other trigger point injections.