Shockwave therapy, also known as extracorporeal shockwave therapy (ESWT), is a non-invasive treatment that uses high-energy sound waves to treat chronic pain and injuries. It aims to accelerate the body’s natural healing process.
There are two main types of shockwave therapy:
- Focused shockwave therapy: Uses focused shockwaves that can reach up to 10 times the energy intensity of radial shockwaves. The waves can be targeted to a specific area and penetrate deeper into the tissues.
- Radial shockwave therapy: Uses radial pressure waves that are more superficial and dispersed over a larger area.
Evidence of Shockwave for neck pain
There is evidence that shockwave therapy can be an effective treatment option for neck pain.
Several studies have found that extracorporeal shockwave therapy (ESWT) results in reduced pain and improved function in patients with myofascial pain syndrome in the neck and shoulder area:
- A 2021 randomized controlled trial found that focused ESWT showed significant improvement in pain relief compared to other treatments for myofascial neck pain[1].
- A 2020 randomized trial found that ESWT led to reduced pain intensity and improved neck disability in patients with neck and upper back myofascial pain compared to standard care[2].
- A 2020 study on patients with cervical myofascial pain after neck dissection surgery concluded that ESWT was an effective and safe treatment that significantly reduced pain[4].
How shockwaves generate mechanical forces
- Focused shockwaves converge and reach peak pressure at a targeted depth, allowing precise delivery of energy.
- The high positive pressure of the shockwave compresses tissue, while the negative pressure creates tension and cavitation bubbles that collapse violently.
- The rapid pressure changes produce shear, strain, and stress forces that mechanically disrupt tissues.
- Radial shockwaves disperse energy over a wider area with less focused mechanical forces.
Cavitation and its effects
- The collapse of cavitation bubbles releases enormous amounts of energy, generating secondary shockwaves and jet streams that damage cell membranes.
- Cavitation causes microtearing of muscle fibers and connective tissue, breakdown of calcifications, and hemorrhage.
- The violence of cavitation is proportional to the pressure amplitude – high energy focused shockwaves have greater cavitation effects.
Acoustic streaming
- Acoustic streaming refers to fluid flows generated by ultrasonic wave propagation.
- Shockwaves induce vortices and microstreaming around cell membranes and tissue structures.
- This mechanical stimulation enhances cell permeability, uptake of molecules, and activation of signaling pathways.
Other effects
- Shockwaves exert radiation forces that can deform cell membranes and cytoskeletal structures.
- Shear stresses directly activate membrane receptors like integrins to trigger intracellular signaling cascades.
- Shockwaves have been shown to permeabilize cell membranes in a process known as sonoporation.
Mechanism of Shockwave Therapy for pain
The proposed mechanisms by which shockwave therapy alleviates neck pain include:
- Mechanical disruption of trigger points and muscle spasms[6][7].
- Increased blood flow and metabolic changes that aid healing[3][5].
- Activation of pain signaling pathways and inflammation modulation[3][11].
- Stimulation of tissue regeneration[3][5][15].
The combination of these biological effects helps treat chronic injuries, reduce pain, and accelerate healing in conditions like tendinopathies, plantar fasciitis, and bone fractures. Multiple treatments are usually required for optimal results.
Conclusion
While several studies demonstrate benefits, more high quality research is still needed to fully establish the efficacy of shockwave therapy for neck pain treatment[9][12].
Overall, it appears that ESWT can be a safe, non-invasive option that may provide pain relief for some patients with chronic neck pain caused by myofascial trigger points or other musculoskeletal issues. However, outcomes may vary based on the cause and severity of neck pain.
References:
[1] https://pubmed.ncbi.nlm.nih.gov/32520797/
[2] https://journals.sagepub.com/doi/full/10.1177/0269215520947074
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7275282/
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655229/
[5] https://pubmed.ncbi.nlm.nih.gov/32523286/
[6] https://softwaveclinics.com/blog/shockwave-therapy-for-neck-pain/
[7] https://my.clevelandclinic.org/canada/services/shockwave-therapy
[8] https://www.kjsm.org/journal/view.html?doi=10.5763%2Fkjsm.2020.38.4.208
[9] https://www.physio-pedia.com/Extracorporeal_shockwave_therapy_(ESWT)
[10] https://www.metrohealthnyc.com/shockwave-therapy-to-treat-neck-and-back-pain/
[11] https://journals.lww.com/jbjsjournal/fulltext/2018/02070/the_role_of_extracorporeal_shockwave_treatment_in.13.aspx
[12] https://clinicaltrials.gov/ct2/show/NCT05381987
[13] https://www.frontiersin.org/articles/10.3389/fendo.2023.1188297
[14] https://clinicaltrials.gov/ct2/show/NCT04495465
[15] https://www.sciencedirect.com/science/article/abs/pii/S0976566220300631
[16] https://www.sciencedirect.com/science/article/pii/S1607551X15001230
[17] https://complete-physio.co.uk/services/shockwave-therapy/
MD, PhD. Physical Medicine & Rehabilitation Physician from São Paulo - Brazil. Pain Fellowship in University of São Paulo.