Ashi Acupuncture Versus Local Anesthetic Trigger Point Injections in the Treatment of Abdominal Myofascial Pain Syndrome: A Randomized Clinical Trial

Abdominal myofascial pain syndrome (AMPS) is a condition that significantly affects women with chronic pelvic pain, characterized by hyperirritable trigger points in the abdominal muscles. This randomized controlled trial compared the efficacy of two therapeutic approaches: ashi acupuncture, a centuries-old Chinese technique that uses needles at painful points, and local anesthetic injections at trigger points. The research was conducted at a tertiary university hospital in Brazil, including 35 women with confirmed chronic pelvic pain secondary to AMPS. Participants were randomized into two groups: 16 received ashi acupuncture (10 weekly 25-minute sessions) and 19 received 1% lidocaine injections (4 weekly applications).

Pain was assessed using validated scales (Visual Analog, Numerical Categorical, and McGill Pain Questionnaire) before, during, and after treatments, with follow-up of up to 6 months. Results demonstrated that both treatments were equally effective in reducing clinical pain. The acupuncture group showed pain reduction from 6.7 to 2.9 points on the visual analog scale, while the anesthetic group reduced from 6.7 to 3.9 points. There was no statistically significant difference between groups, except on the McGill Questionnaire after one week, where acupuncture proved temporarily less effective.

In terms of safety, both treatments showed minor adverse events. In the acupuncture group, 50% of patients had ecchymoses at the application sites, in addition to isolated cases of headache and abdominal distension. In the anesthetic group, 37% developed ecchymoses, with some cases of headache, numbness, and dizziness. All events were considered mild and resolved spontaneously.

From a mechanistic standpoint, ashi acupuncture acts through stimulation of specific trigger points, promoting pain modulation by peripheral and central mechanisms, including the release of vasoactive substances and growth factors. Local anesthetic, in turn, interrupts nerve conduction by blocking sodium channels. The clinical implications are significant, as the study provides evidence that acupuncture may be a valid alternative to anesthetic injections for women with AMPS, especially considering that acupuncture does not involve medications and may have lower long-term neurotoxicity risks. This is particularly relevant for patients who prefer non-pharmacological approaches or who have contraindications to local anesthetics.

The study also contributes to the understanding of ashi acupuncture as a specific technique for treating trigger points, distinguishing it from other acupuncture modalities by directly focusing on sites of myofascial pain.