Five Things to Know: The Effects of Acupuncture on Carpal Tunnel Syndrome

Person holding wrist in pain

In a new study reported in the journal Brain, investigators at the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital shed new light on how acupuncture provides measureable improvements for chronic pain patients. Here are five things to know:

  1. Acupuncture is a therapy that originated in China several thousand years ago that involves sticking tiny needles into the body in an effort to produce a variety of beneficial health effects, primarily pain relief. Studies exploring acupuncture’s effect on chronic pain disorders have shown that it may be marginally better than a placebo in reducing patient-reported pain, but researchers still want to know exactly how does acupuncture work? And is it any better at improving measurable objective outcomes for chronic pain?
  2. To get to the root of these questions, investigators at Mass General looked at the connection between acupuncture and carpal tunnel syndrome (CTS), a nerve pain disorder. Why CTS? It’s one of the few chronic pain disorders associated with objective measurable changes in the body. Because CTS is a result of compression of the median nerve in the arm, impulses between the wrist and the forearm, such as motor function and sensation, are slowed down. Additionally, studies have shown that the brain – particularly the part that receives touch-related signals – is remapped in CTS. Specifically, brain cells that usually respond to touch signals from individual fingers start to respond to signals from multiple fingers.
  3. The study split 80 participants with CTS into three groups that received one of three treatments: electro-acupuncture at the affected hand, electro-acupuncture at the ankle opposite the affected hand, or sham electro-acupuncture with placebo needles near the affected hand. Results were measured before and after eight weeks of therapy sessions (16 sessions in total) using a questionnaire and MRI scans.
  4. Researchers found that participants in all three groups reported improvements in the pain and numbness they were feeling after the treatments. However, there were notable differences in physiologic measures. Participants who received real acupuncture either at the affected hand or at the ankle saw improved nerve impulses in the wrist. Additionally, only those that received real acupuncture at the affected hand experienced brain remapping that was also linked to long-term improvement in CTS symptoms. No physiologic improvements resulted from sham acupuncture.
  5. Researchers plan to follow up this study with further research linking objective/physiological and subjective/psychological outcomes for acupuncture-produced pain relief. Better understanding of how acupuncture works to relieve pain – and the ability to point to objective scientific measures demonstrating its effectiveness – could help to improve non-pharmacological care options for chronic pain patients.

Vitaly Napadow, PhD, director of the Center for Integrative Pain Neuroimaging at the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital is senior author of this study. Read more here.

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