According to Gattie et al (2017) dry needling is a technique in which a fine needle is used to penetrate the skin, subcutaneous tissues, and muscle, with the intent to mechanically disrupt tissue without the use of an anesthetic.
Dry needling is often used to treat myofascial trigger points (MTrPs), which are described as localized hypersensitive spots in a palpable taut band of muscle. These hyperirritable spots can be classified as active MTrPs when they produce spontaneous pain and, when palpated, reproduce a patient's familiar pain. Latent MTrPs do not produce spontaneous pain and are only painful upon palpation. Myofascial trigger points are commonly found in patients with musculoskeletal pain.
The physiological mechanism underpinning the effects of dry needling remains to be elucidated. However, it has been suggested that dry needling may produce both local and central nervous responses to restore homeostasis at the site of the MTrPs, resulting in a reduction of both peripheral and central sensitization to pain. In their paper they declare Tsai et al (2010) demonstrated that needling of distal trigger points causes a reduced sensitivity of proximal trigger points. Centrally, dry needling may activate descending control mechanisms in the brain or spinal cord. Dry needling has been shown to immediately increase pressure pain threshold (PPT) and range of motion, decrease muscle tone, and decrease pain in patients with musculoskeletal conditions.
Since 2013 75% of studies concluded that dry needling is more effective in the short term for decreasing pain when compared to sham or placebo treatment. There is currently weak evidence (only 25% of systematic reviews) for dry needling's effect on functional outcomes or quality of life. It is fair to say more research is required to determine the long term affects and benefits of Trigger Point Dry Needling.
Gattie, E., Cleland, J. and Snodgrass, S. (2017). The Effectiveness of Trigger Point Dry Needling for Musculoskeletal Conditions by Physical Therapists: A Systematic Review and Meta-analysis. Journal of Orthopaedic & Sports Physical Therapy, 47(3), pp.133-149.