Short-term effect of acupuncture dry needle in treatment of chronic mechanical low back pain: a randomized controlled clinical trial

Dry needling acupuncture has shown promise as an alternative for the treatment of chronic mechanical low back pain, a condition that affects between 60% and 90% of the working-age population in industrialized countries. This condition represents not only significant individual suffering but also a major public health problem, generating high economic costs due to intensive use of medical services and time off work. Chronic mechanical low back pain is characterized by persistent pain and limitation of physical function, and can also impact mental health and increase the risk of other comorbidities.

The origin of this pain is frequently related to the presence of myofascial trigger points, which are hyperirritable regions located in taut bands of skeletal muscle. These points may be active, causing spontaneous and referred pain that reproduces the patient's pain pattern, or latent, only limiting range of motion and potentially causing muscle weakness. The formation of these trigger points is associated with reduced local blood flow, deficiency of oxygen and nutrients, and accumulation of toxic substances that stimulate pain nerve endings, creating a cycle of pain and functional limitation.

To investigate the efficacy of dry needling acupuncture as a short-term treatment for this condition, investigators conducted a randomized controlled clinical trial involving 30 participants with nonspecific low back pain, aged 20 to 45 years. The primary objective was to evaluate whether this technique could provide pain relief, improve functional disability, and increase lumbar spine range of motion. Participants were carefully selected, including only those with moderate to severe pain (between 30 and 70 points on a 100-point scale), with at least four muscles showing trigger points on each side, and with documented history of myofascial pain syndrome in the lumbar region.

The study used rigorous methodology, randomly dividing participants into two groups. The experimental group received dry needling treatment directed at specific trigger points in muscles important for lumbar stability, including the piriformis, gluteus medius, quadratus lumborum, and lumbar iliocostalis, in addition to strengthening and stretching exercises. The control group performed only the strengthening and stretching exercises. The dry needling technique involved inserting solid filiform needles into trigger points identified by palpation, seeking to elicit the local twitch response, which is considered crucial for the therapeutic effect.

The needles remained in the points for 7 to 10 minutes, and treatment was performed over four weeks.

Study results were highly encouraging and statistically significant. Both groups showed improvement after treatment, but the group that received dry needling acupuncture demonstrated superior benefits in virtually all aspects evaluated. Pain intensity decreased substantially by 45.18% in the acupuncture group, compared with 19.46% in the control group. Range of motion also showed impressive improvements: lumbar flexion increased 82.7% in the acupuncture group versus 28.26% in the control group, while extension improved 52.63% compared with 29.25%.

Interestingly, lateral flexion capacity showed significant reductions in movement limitation, with improvements of approximately 8% in the acupuncture group compared with more than 45% in the control group, indicating greater normalization of function. Regarding functional disability, measured through the Oswestry questionnaire, both groups showed similar improvements, with reductions of 35.07% in the acupuncture group and 28.49% in the control group.

For patients suffering from chronic mechanical low back pain, these results offer hope of an effective and relatively safe therapeutic option. Dry needling acupuncture may be particularly attractive because it is a minimally invasive treatment without medication use, that can provide significant pain relief and functional improvement in a relatively short time. For health professionals, the study provides solid scientific evidence that this technique can be a valuable addition to the therapeutic arsenal, especially when combined with appropriate exercises. The technique proved safe, with no significant adverse effects reported, which is important considering that many conventional treatments for low back pain may have undesirable side effects.

The mechanisms by which dry needling acupuncture produces its beneficial effects are multiple and well grounded scientifically. From a mechanical standpoint, needle insertion may provide localized lengthening of shortened sarcomeres and contracted cytoskeletal components within the trigger point, allowing the muscle to return to its normal resting length. Neurologically, the technique can activate A-delta nerve fibers that stimulate inhibitory interneurons in the spinal cord, blocking pain transmission. Chemically, eliciting the local twitch response can normalize elevated levels of inflammatory and pain substances at the trigger point site.

Additionally, studies suggest that the technique can improve local microcirculation, increasing blood flow to the skin and muscles in the treated region.

It is important to recognize some limitations of this study that patients should consider. The sample size was relatively small, with only 30 participants, and follow-up was short-term, not allowing assessment of long-term durability of benefits. The study focused specifically on young to middle-aged adults with nonspecific mechanical low back pain, so results may not be applicable to all forms of low back pain or to all age ranges. In addition, it was not possible to perform a fully blinded study because of the nature of the intervention, which may have partially influenced results.

Despite these limitations, this study contributes significantly to the growing body of evidence supporting the use of dry needling acupuncture in the treatment of chronic mechanical low back pain. Results suggest that this technique can offer substantial pain relief, functional improvement, and increased range of motion when applied by appropriately trained professionals. For patients seeking alternatives to conventional treatments or wishing to avoid prolonged medication use, dry needling acupuncture represents an evidence-based therapeutic option that deserves consideration, always under the guidance and supervision of qualified health professionals.