Effect of Dry Needling Plus Vibration on Myofascial Trigger Points in Individuals With Nonspecific Low Back Pain

Low back pain is one of the most common health issues worldwide, and in most cases, this pain is nonspecific low back pain (NSLBP). NSLBP is characterized by the inability to determine the real source of the pain and commonly presents with myofascial trigger points (MTrPs) in the muscles related to the lumbar region.

One of the most widely used techniques for treating NSLBP by targeting MTrPs is dry needling (DN), a technique that involves inserting a needle to produce a mechanical effect capable of "deactivating" the MTrP and thereby alleviating its symptoms. However, some studies have concluded that other techniques are more effective than DN, such as percutaneous electrolysis (PE).

When using the PE technique, it appears that adding a galvanic current enhances the effects of DN. Nonetheless, this poses a greater risk to the patient, as the galvanic current could damage nervous tissue if it comes into contact. For this reason, it is proposed to investigate whether other physical agents that are not electrical could enhance the effect of DN without increasing its risk. This is the case for vibration, a stimulus that has already been used successfully for the treatment of MTrPs, allowing us to investigate whether adding vibration to DN introduces therapeutic capabilities that:

* Maintain or increase the effectiveness of DN in terms of pain and functional capacity.
* Do not add risks for the patient, unlike PE.
* Are less painful than DN and cause less post-needling pain than that generated after successive needle insertions with DN. Emphasizing these adverse effects is necessary since most clinical trials do not report these variables, which is fundamental for describing the safety of invasive techniques.

Following this idea, the present project will analyze a new invasive therapy for the treatment of MTrPs: dry needling with vibratory stimulus (DN+V), for which the following hypotheses are proposed:

* DN+V, instead of using an electrical stimulus like PE that could cause damage to some tissues, will apply vibration to the DN needles to increase the mechanical stimulus exerted on the MTrP, expecting greater benefits in terms of pain, functional capacity, muscle strength, and other variables of interest in individuals with NSLBP, and possibly requiring less treatment time than DN.
* In DN, the repeated insertions and withdrawals of the needle in the MTrP provoke a hemorrhagic and inflammatory reaction that translates into hypersensitivity and microscopic tissue injury in the muscle, causing pain during treatment and post-needling pain for the following 24-32 hours. Another study showed that PE caused less post-needling pain than DN, which may be due to the fact that, unlike DN, it is common in PE to only perform a single puncture with each needle and not mobilize them.
* The methodology for DN+V will be the same as for PE, with a single puncture and no needle manipulation, so it is expected that DN+V, being less invasive than DN, will reduce pain during treatment and post-needling pain compared to that generated by DN. There are studies that support this hypothesis, concluding that needle manipulation in DN produces greater post-needling pain than DN without needle manipulation.

This study aims to evaluate the efficacy of a new invasive therapy for treating MTrPs: dry needling with vibratory stimulus (DN+V). The following hypotheses are proposed:

* DN+V will utilize vibration on the dry needling needles instead of an electrical stimulus like in percutaneous electrolysis (PE), which could potentially damage some tissues. The expectation is that DN+V will increase the mechanical stimulus applied to the MTrP, yielding greater benefits in terms of pain relief, functional capacity, muscle strength, and other variables of interest in individuals with NSLBP, possibly requiring less treatment time compared to DN alone.
* In DN, repeated insertions and withdrawals of the needle into the MTrP provoke a hemorrhagic and inflammatory reaction that results in hypersensitivity and microscopic tissue injury in the muscle, causing pain during treatment and post-needling pain for the next 24-32 hours. A study showed that PE caused less post-needling pain than DN, likely because PE typically involves a single puncture per needle without needle manipulation.
* DN+V will follow the same methodology as PE, with a single puncture and no needle manipulation. Thus, it is expected that DN+V, being less invasive than DN, will reduce pain during treatment and post-needling pain compared to DN. A study supports this hypothesis, concluding that needle manipulation in DN produces greater post-needling pain than DN without needle manipulation.

To test these hypotheses, a randomized clinical trial will be conducted: "RCT: Analysis of the Effectiveness on Pain in Individuals with Nonspecific Low Back Pain by Adding a Percutaneous Vibratory Stimulus to Dry Needling in the Treatment of MTrPs."

EXPECTED RESULTS This initial study will provide the first data on DN+V, focusing on whether DN+V is easy to apply, well-tolerated by patients, and shows effects similar to or better than DN in reducing NSLBP.

METHODOLOGY

* Instrumentation and Evaluation Method: A group of specialized physiotherapists will evaluate each participant for MTrPs in muscles related to NSLBP. Identified MTrPs will be included in the study.
* Variables: For this initial RCT, only the main variables will be considered (NSLBP, pain during treatment, and post-needling pain). These will be evaluated using the Numeric Pain Rating Scale (NPRS).
* Intervention: Participants will be randomized into two groups: DN (without vibration, considered the control group) and DN+V (vibration for 10 minutes).
* Follow-up: NSLBP will be evaluated before and after the intervention, and at 24 and 48 hours. Pain during treatment will be recorded immediately after the intervention. Post-treatment pain will be evaluated 48 hours later, asking each participant how long post-needling pain lasted if it occurred.

TRANSFER AND DISSEMINATION OF RESULTS The development of this treatment technique for MTrPs will involve creating a "know-how" that encompasses all knowledge and application methodology related to DN+V. This dissertation will demonstrate the effectiveness and cost-effectiveness of DN+V, but this will only be the starting point of the "know-how," as further research will be necessary to address current uncertainties (e.g., does the entire population and all musculature respond the same way?) and to refine the application methodology (optimal dose of time/intensity/frequency of vibration, possible combination with physical exercise, etc.).

Once the "know-how" has been validated and scientifically supported, efforts will be made to disseminate it. Through presentations, courses, and training sessions, the DN+V technique will be promoted to advance clinical practice among physiotherapists. An example of a successfully implemented "know-how" in physiotherapy is the "DNHS" technique (www.dnhs.es), a dry needling technique specifically developed for neurological patients by Dr. Pablo Herrero, the director of the doctoral thesis in which this study is included.

When the "know-how" of the DN+V technique gains popularity among health professionals, its economic potential will be exploited. Similar to other treatment techniques like PE, specific devices for DN+V application will be developed, and training sessions will be conducted to ensure proper use of the technique. This will generate economic returns for the researchers and promoters involved in the development of the DN+V technique.

Eligibility Criteria:
Inclusion Criteria:

* Individuals with nonspecific low back pain, defined as pain persisting for more than 3 months between the twelfth rib and the buttocks, registering a Numeric Pain Rating Scale (NPRS) score of 3 or higher prior to the intervention. Additionally, participants must meet the following criteria:
* Presence of myofascial trigger points (PGMs) in any of the following muscles relevant to the project: erector spinae (longissimus and iliocostal), multifidus, gluteus maximus, gluteus medius, and quadratus lumborum. Detection of these PGMs will be conducted by a specialized physiotherapist.
* Individuals aged 18 years or older, proficient in either Spanish or English. Participants who have provided informed consent by signing the consent form

Exclusion Criteria:

* Diagnosis of lumbar pain associated with specific pathologies such as disc herniations or neurological disorders.
* Recent infiltration therapy within the past 3 months.
* Recent manual therapy, acupuncture, or dry needling interventions in the lumbopelvic region within the last 4 weeks.
* Previous surgical intervention in the lumbopelvic region.
* Leg length discrepancy (\>1 cm).
* Recent use of anticoagulant or antiplatelet medications within the last week.
* Systemic or local infection in the lumbar region.
* Pregnancy.
* Needle phobia (belonephobia).