Dry needling of the gluteus-medius muscle, combined with standard care, for chronic low back pain – a pilot randomized sham-controlled trial

ABSTRACT

Background

Individuals with low back pain (LBP) often exhibit weakness and the presence of trigger points in their Gluteus Medius (GMe) muscle.

Objectives

To examine the effectiveness of adding dry needling (DN) for the GMe to standard care of active physical therapy in patients with chronic nonspecific LBP.

Methods

A randomized, prospective, sham-controlled trial was conducted. Participants with chronic nonspecific LBP (N = 22, age range: 31–55 years) were randomly divided into intervention and control groups. Both groups received active physical therapy including exercises for 6 treatments. In addition, at each session, the intervention group received deep DN to their GMe muscle, and the control group received sham needling. Outcome measures included level of pain (using VAS scale), function (Oswestry disability index ODI), low back range of motion (ROM) (forward flexion and schober tests), and global rating of change. The research group was further divided into moderate and minimal disability according to the ODI.

Results

The research group showed greater improvement in pain level compared with control (p = 0.01). The change in ODI was higher in the moderate LBP group compared with the control group (B = 5.25, p < 0.05). The change in forward flexion distance test was higher in the moderate disability LBP group compared with the control group (B = 6.31, p < 0.01). Simple mean analysis also revealed a significant difference between the moderate and minimal disability groups (B = 6.16, p = 0.01)

Conclusions

Incorporating DN into physical therapy treatments for chronic nonspecific low back pain, can improve pain level and function.

Clinical trials registration no

NCT04498572 (clinicaltrial.gov).

1. Introduction

Low back pain (LBP) is a common musculoskeletal problem worldwide. It is estimated that approximately 85% of individuals will experience low back pain at some point in their lives and its lifetime and point prevalences are estimated to be over 75% and 28%, respectively [1–3]. This can cause significant levels of disability that affect an individual’s quality of life and ability to work [4].

One of the key characteristics of lower back pain is the impaired function of muscles in the lumbopelvic-hip complex. Individuals with LBP often exhibit weakness, atrophy, and reduced activation of their Gluteus Medius (GMe) muscle. These might lead to decreased hip abduction force output, an increased number of trigger points in this muscle, and higher local sensitivity [5–8]. Adding strengthening exercises to the thigh muscles, in addition to other lumbar stabilization exercises, was found to be effective for chronic LBP causing improvement in pain and level of disability [9,10].

Trigger points in the GMe can cause referred pain mainly to the buttock area along the iliac crest and medially above the sacrum area [11,12]. Trigger points are hypersensitive points in skeletal muscle that are associated with a hypersensitive palpable nodule in the muscle. Two main trigger points are usually described namely active and latent trigger points. Active trigger points can cause spontaneous pain while latent ones are only painful on palpation and the pain is not familiar to the person as the pain they experience as part of their clinical complaint [13]. A recent Delphi survey suggests that at least two out of three of the following- taut band, hypersensitive spot, and referred pain should be present to identify trigger points. Furthermore, the study indicates that active trigger points should evoke the familiar symptoms experienced by the patient [14].

Dry needling (DN) is an intervention method that uses needles inserted into connective tissues, muscles, and trigger points. Studies show that DN is effective in reducing pain and sensitivity, and improving range of motion and function among LBP patients, especially when used in combination with other treatment modalities [4,15].

A muscle twitch can occur during DN intervention. Researchers have shown that this reaction, called local twitch response, might be significant for pain relief and should be established during DN treatment [16–18]. Yet, some studies claim that the twitch response is not correlated with changes in pain and disability [19,20].

Most studies conducted on DN for low back pain have focused specifically on needling of the back muscles [21–23]. Following the association between LBP and GMe muscle [5,6,8], there is a need to examine the effectiveness of needling to this muscle on LBP symptoms. This study aims to examine the effectiveness of active exercises combined with DN for the GMe muscle in patients with chronic nonspecific LBP on pain, range of motion, and function.

2. Materials and methods

2.1. Study design

The present study was a randomized clinical sham-controlled trial with two parallel groups. The study was approved by the Institutional Review Board of the Faculty of Social Welfare & Health Sciences, University of Haifa, (#403/20) and all participants signed a consent form following verbal instructions describing the procedure. The rights of participants were protected. The paper is reported according to CONSORT guidelines and was registered prospectively on a public clinical trial database. Clinical trial registration no: NCT04498572 (clinicalTrials.gov).

2.2. Participants

Twenty-two healthy volunteers (age ranged 31–55 years), suffering from chronic nonspecific low back pain admitting to physical therapy treatments, were recruited to this study. Inclusion criteria were as follows: healthy, independent in the activities of daily living, suffering from nonspecific low back pain for more than three months, a complaint of pain in the lower lumbar, sacrum or gluteal areas, a score of more than 3/10 on the visual analog scale for self-rated pain, and the presence of hypersensitive points in their gluteus medius area reproducing their familiar symptoms. Exclusion criteria were: neurologic signs such as neurological weakness, loss of sensation or reflexes, radicular pain, pregnancy, patients undergoing other treatments, history of back, pelvic, or hip surgery or fractures in the past, and contraindications for DN such as local or systemic infections, local trauma, fear of needles, and anticoagulants use (only as a precaution). The condition studied in the research was nonspecific low back pain, defined as back pain not attributable to diagnosed specific pathology (e.g. infection, tumor, osteoporosis, fracture, structural deformity, inflammatory disorder, radicular syndrome, or cauda equina syndrome). As such, all of these conditions were excluded [24]. The study was conducted at a private physical therapy clinic. Participants were recruited through advertisements in general physician and therapist clinics, as well as on social media in the area.

2.3. Allocation and randomization

The participants were randomly divided into one of the following two groups: 1. research group; 2. control group. An equal number of cards with the group option were prepared and folded into sealed envelopes. The therapist opened the corresponding envelope after baseline data examination to adapt the intervention to each participant. Participants were blinded to their assigned group.

2.4. Baseline examination and outcome measurements

The baseline examination involved self-reported questionnaires and a physical examination, which were further used to assess the effectiveness of the intervention.

Each participant completed the following questionnaires:

1. Demographic characteristics questionnaire – including age, height, weight, physical activity, LBP history.

2. The Oswestry disability index (ODI) – to assess the disability level associated with LBP. The actual score was given in a percentage format (0–100%); the higher the score, the greater the disability associated with LBP. This questionnaire was found to be valid and reliable for assessing LBP [25].

3. Visual Analog scale (VAS) – to assess the level of pain on a scale of 0–10 when 0 represents no pain and 10 represents most severe pain. The VAS scale is a common, valid, and reliable tool to assess pain levels among LBP patients [26].

Upon completion of the questionnaires, the participants went through a physical exam including the following:

1. Modified Schober lumbar flexion test – the participants were asked to perform forward flexion from a standing position. The increase in distance between the lumbosacral junction point and 15 cm above this junction was measured by measurement tape (in cm). This test has moderate validity (r = 0.67; 95% CI 0.44–0.84) and excellent reliability (intra: ICC = 0.95; 95% CI 0.89–0.97; inter: ICC = 0.91; 95% CI 0.83–0.96) [27].

2. Forward flexion distance test - the distance between the third fingertip and the floor is measured during forward flexion of the spine from a standing position (in cm). The test previously showed an intraclass correlation coefficient of 0.93. The Schober lumbar flexion test and the Forward flexion distance test were recommended to be used in combination when examining patients for low back range of motion (ROM) [28].

3. Palpation of the GMe area for assessing the presence of trigger points. The most hypersensitive point that produced the patients’ symptoms during palpation was selected for the area of DN intervention.

2.5. Intervention

Following baseline examination, participants were randomly divided into two groups: research group who received exercises followed by DN to their GMe muscles and control group who received the same exercises followed by placebo DN to their GMe muscle. DN was performed following exercises to avoid potential soreness that could affect exercise performance. Treatments were conducted twice a week and up to six sessions. Six treatments were chosen based on previous studies and the fact that most physiotherapy interventions require a series of consecutive sessions [16,29,30].

At the end of the last treatment participants from both groups underwent another evaluation including ODI, VAS, ROM tests, and global rating of change (GROC). The GROC scale determines the effect of an intervention. The scale ranged from −7 (‘very worse’) to 0 (‘about the same’) to + 7 (‘large improvement’) [31].

All measurements and interventions were performed by a physical therapist (A.G.) with a certificate in DN and 9 years of clinical experience, who utilized DN daily during physical therapy treatments.

2.5.1. Exercise program

The exercise program included mobility, stretching, stabilization, and strengthening exercises normally used in community physiotherapy clinics. The exercises were chosen according to previous studies that found positive effects of exercises on LBP symptoms [2,32–34]. Both groups received the same exercise program including the following: side-lying hip abduction (clamshell exercise), four-point kneeling alternate arm and leg extension exercise, supine trunk rotation with feet raised, double leg (bilateral) squat, standing on one leg on an uneven surface, GMe stretching and erector spine stretching. Each strengthening exercise was performed in three sets of 10 repetitions bilaterally, and stretching exercises were performed in three sets of 20 sec holds. The participants were instructed to perform the exercises both at home and during each session under the therapist’s supervision.

2.5.2. Dry needling

The needles used in this study were Seirin single-use sterile acupuncture needles (0.30mmX50mm, Jiajian Medical Instrument Co. Ltd, China). DN was applied to the painful side while participants were in side lying on their non-painful side with knees and hips bent to 90 degrees flexion. Palpation in the gluteal region while alternately abducting the hip was carried out to identify the correct muscle and trigger points (TrPs) in the GMe. After the skin was cleaned with 70% alcohol solution, the needle was inserted using back-and-forth movements (fast in and fast out technique) into the TrP until the familiar symptoms were reproduced or a local twitch response was noticed. This movement was maintained until the pain resolved and the twitch response faded or up to ten repetitions [35,36]. A maximum of three trials were performed to find the local twitch response. As the literature is controversial regarding the significance of eliciting the twitch response, limiting the trials was practical and following the suggestion that the treatment can be effective without eliciting a twitch response [20].

The sham DN group underwent the same procedure as the DN group including palpation while alternately abducting the hip to locate the correct muscle and TrP. The needles used in the Sham group were blunted and sanded so they would not pierce the skin but still give a pricking sensation. To add reliability the researcher made the same back-and-forth moves with the needle as if it were real DN [37,38].

2.6. Data analysis

All analyses were performed using RStudio (R Foundation). A p-value of 0.05 was considered significant. Descriptive statistics were calculated for demographic and participant characteristics. Normality tests were carried out by Kolmogorov Smirnoff test. When 2 groups were compared (LBP vs. control), the T-test/Wilcoxon two sample test, or Pearson chi-square test was used, depending on the nature of the distribution. Paired t-tests or the Wilcoxon signed rank sum test were used to evaluate the changes in all parameters after treatment for all sample. We further divided the LBP participants according to Oswestry disability index categories for function evaluation following intervention into participants with minimal disability: 0–20% and moderate disability: 20–40% [39].

The statistical analysis followed the intention-to-treat principle, comparing the change values of the outcomes between three groups (LBP minimal disability, LBP moderate disability, and Control). In the first phase, a one-way ANOVA with post hoc pairwise comparisons adjusted using Tukey’s multiple comparison method was conducted. In the second phase, change values were assessed using a linear regression model that included the group as a factor and controlled for the baseline value of the dependent variable. Least-square means were derived for each group, and group comparisons were performed by applying appropriate linear contrasts to the model. The results were not adjusted for multiple testing. Cohen effect size was calculated and interpreted as 0.01 partial eta squared effect as small, 0.06 medium, and 0.14 as large [40].

3. Results

Twenty-two participants were initially recruited for the study, with two participants dropped out after two treatments for personal reasons. The study flow diagram can be viewed in Figure 1. Twenty participants completed the study, 10 in the research group (five women and five males) and 10 in the control group (four women, six males) with age ranged 31–55 years. The average age in the research group was slightly lower than the average age in the control group (37 ± 6.1 compared to 43 ± 5.9 years, p = 0.031). No significant differences were found between research groups in other demographic parameters (p > 0.05) (Table 1). Approximately 60% of all participants in the study reported their work as a sedentary job, 70% reported low back pain for over a year, and 60% performed physical activity regularly, without differences between research groups.

Figure 1.

The study flow diagram.

Table 1.

Demographical characteristics of the research group.

	Research group (N = 10) X±(SD)	Control group (N = 10) X±(SD)	Total sample (N = 20) X±(SD)	p-value (between groups)
Age (years)	36.10 (±4.0)	43.0 (±5.9)	(±6.7)39.5	0.031*
BMI	(±1.8)24.42	(±1.9)24.05	(±1.9)24.24	0.669
Height (cm)	(±10.2)173.10	(±10.8)173.0	(±10.2)173.05	0.983
Body mass (Kg)	(±9.8)73.40	(±6.4)71.70	(±8.1)72.55	0.651

*Significant difference (p < 0.05). BMI – Body Mass Index (weight in kilograms divided by height in meters squared).

3.1. Visual analog scale assessment

The lowest level of pain for the entire sample pre-intervention was three on the VAS scale and the highest was 10. The lowest level of pain at the end of treatments was zero and the highest was six. A significant improvement in pain levels following intervention was found in both groups (p < 0.05), yet, the research group showed greater improvement (reduction) in pain level compared with control (4.6 (±2.4) vs. 2.0 (±1.6) respectively, p = 0.01) (Table 2).

Table 2.

VAS assessment pre and post-intervention in research groups.

	Research group (N = 10) X±(SD)	Control group (N = 10) X±(SD)	Total sample (N = 20) X±(SD)	p-value (between groups)	Effect size
VAS T1	(2.3±) 6.8	(1.9±) 5.0	5.7 (±2.2)	0.07	0.12
VAS T2	(2.0±) 1.9	(1.9±) 3.0	2.4 (±1.9)	0.22	0.12
Delta pre-post VAS	(2.4±) 4.6	(1.6±) 2.0	3.3 (±2.3)	0.01*	0.33

VAS – Visual Analog Scale, VAS T1- beginning of study, VAS T2- end of intervention program, delta – change in VAS post treatment- VAS pre-treatment.

*Significant difference (p < 0.05).

3.2. Function assessment

Oswestry disability index categorizes individuals according to their disability. We further divided the research group according to Oswestry categories for the examination of function following intervention into participants with minimal disability: 0–20% and moderate disability: 20–40% [39]. Improvement in function was found for the entire sample (p < 0.05), additionally, the change in ODI was higher in the moderate LBP group compared to the control group (B = 5.25, p < 0.05) (Table 3).

Table 3.

Linear regression model results, testing the effect of group on changes in measured variables while controlling for the baseline value of the dependent variable.

	Schober_test_ delta	forward_flexion_distance_delta	ODI_delta
Predictors	B(SE)	B(SE)	B(SE)
(Intercept)	0.91 (1.14)	−1.14 (1.21)	2.08 (1.22)
group moderate disability vs control	−0.30 (0.55)	6.31 ** (1.67)	5.25 *(2.00)
group minimal disability vs control	−0.29 (0.55)	0.15 (1.68)	0.64 (1.38)
baseline	−0.02 (0.18)	0.20 (0.10)	0.06 (0.14)
Observations	20	20	20
ES group	0.03	0.46	0.54

ES: partial η², effect size, according to [40] considered 0.01 partial eta squared effect as small, 0.06 considered medium and 0.14 considered large.

Baseline: the dependent variable value at T1 change is with 2.25 units higher than the control.

Delta = Variable’s value in T1 – T2.

3.3. Range of motion

A significant improvement post-intervention was found in the range of motion for the entire sample both in the Schober test and the forward flexion test (p < 0.05).

The change in forward flexion distance test was higher in the moderate disability LBP group compared to the control group (B = 6.31, p < 0.01). Simple mean analysis also revealed a significant difference between the moderate and minimal disability groups (B = 6.16, p = 0.01) (Table 3).

3.4. Participant perception of improvement

Subjective evaluation of the patient for improvement following treatment was evaluated by the GROC questionnaire. The degree of improvement for the entire sample was 4 indicating a moderate change for the better, in the study group 4.5 (moderate change for the better to quite a bit change for the better), and in the control group 3.5 (a somewhat change for the better to a moderate change for the better) [41]. No difference was found between research groups (p = 0.17).

4. Discussion

DN is a common technique for LBP improving pain, function, and quality of life [4,15]. Most studies examining DN for LBP use needling of the back muscles [21–23]. Due to the relationship between back pain and the GMe muscle we have examined the effect of DN treatment for the GMe muscle combined with active exercise for nonspecific chronic lower back pain.

4.1. Effect of dry needling on pain and function

The results of the current study show a significant improvement in pain and function in the DN group compared with the controls. Similar results were also found in other studies on myofascial pain, hip pain, and neck pain [16,42,43]. Regarding LBP, Rajfur et al. [21] demonstrated that the DN group showed greater improvement in ROM, level of pain, and daily functioning. Similarly, Loizidis et al. (2020) found that DN improved pain levels and functional balance [22]. However, it is important to note that both studies examined DN of the paravertebral muscles, while we used DN of the GMe.

Alvarez et al. [13] examined the effect of DN in the GMe muscle for chronic LBP comparing DN with manual pressure on the latent trigger point. In their work, they performed only one treatment and found a greater improvement in the DN group. Martín-Corrales et al. [44] examined a single session of DN to the GMe for LBP patients in addition to 4 weeks of exercises suggesting that adding DN is beneficial for pain and sensitivity. While these studies examined DN for the GMe similarly to our study, they only utilized a single session compared to the multiple sessions in our study.

In the current study, the research group experienced a pain intensity reduction of over 4 points, while the control group experienced a reduction of 2 points on VAS score. The minimal clinically important change (MCIC) of pain intensity in subacute and chronic LBP patients ranged from 1.5 to 3.2 points in patients with a baseline score below 7 points, and from 2.5 to 4.3 in patients with a baseline score ≥9 point [45].

The changes in our study correspond to these reported clinically important changes implying on the effectiveness of treatment and improvement of patients’ symptoms.

4.2. Dry needling methods

There are no clear recommendations or consensus for DN application techniques, and several techniques can be found in the literature [21]. The depth of needling insertion into the soft tissue is one of the variations in needling application between studies with two techniques deep and superficial needling. While in superficial needling the needle penetrates only the skin, in deep needling the needle is inserted a few centimeters into the muscle itself [46]. In our study, we used the deep needling technique.

Even when using the deep DN technique, different applications can be made as to needle number, twitch response, area of needling, number of treatments, etc. For instance, Taşoğlu et al. [47] investigated the effects of deep needling on myofascial pain syndrome. Two techniques were compared by the researchers. In the first, a needle was placed into the trigger point and left in the tissue motionless for 20 minutes. In the second technique, the needle was placed into the trigger point eight to ten times, back and forth. Both approaches were shown to lessen chronic pain in the study, and there were no differences observed between the research groups. Loizidis et al. [22] performed DN to the back area and left the needles in the tissue for 10–15 minutes and in Tuzun et al. (2017) study, the needles were kept in the muscles for 20 min but were rolled to enable re-stimulation after 10 minutes of treatment [30]. n contrast to the above studies that utilized DN treatment for 15–20 minutes, Téllez-García et al. [48] utilized the fast in fast out technique for 25–30 seconds intending to elicit local twitch responses, similar to the approach used in our study. To conclude the needling method, we used the deep DN for the GMe muscle, with the fast in fast out technique that elicited improvement in patients’ symptoms.

4.3. Sham needling

The control groups in various studies may receive different forms of intervention, such as manual therapy, electrotherapy, exercise, or no intervention at all.

Sham needling has been used in several studies to examine a control group. Similar to our work, Tekin et al. [16] reported using a blunt needle for sham needling, which stings the area but does not penetrate the skin. Rajfur et al. [21] employed telescopic, specially designed placebo needles applied to the skin without puncturing it, enabling gentle movements to mimic actual treatment. In both experiments, DN produced better results for the needling approaches as compared to placebo. The main advantage of a sham needling control group is that it provides the psychological effects of needling, keeping the patients blind to the intervention they are receiving. The sham needling group in our study serves as an adequate control group, further reinforcing the results of the current study.

4.4. Number of treatments

The number of treatments being administered may also have an impact on study results. In our study, participants had up to six treatments administered twice a week for three weeks. This aligns with the findings of the Tüzün et al. (2017) study [30], applying treatment twice per week for a total of six sessions. The study examined DN in comparison to an electrotherapy and active exercise control group, demonstrating improvements in pain and function for the DN group. Mahmoudzadeh et al. [49] administered ten treatments every other day, from which five out of the ten treatments DN was added. Their study examined the effectiveness of DN compared to standard conservative treatment for pain and function in participants with discogenic radiating LBP. The results showed no distinction between groups, with both demonstrating improvement. In contrast, a single treatment was used by Loizidis et al. (2020) to assess the immediate effect of DN [22] suggesting that DN to the back muscles can improve pain and functional balance.

The number of treatments in our study aligns with standard physiotherapy interventions, which typically involve a series of consecutive sessions. This approach evaluates not only the immediate effects of a single session but also the overall impact over three weeks.

Following the above-noted variations in methods regarding DN techniques and the number of treatments applied, it is difficult to compare study protocols and findings.

The strength of our study lies in its design as an interventional randomized study, using sham needling as the control group. The significance of this research is in examining the involvement of the GMe involvement in LBP and needling the GMe muscle as opposed to paravertebral muscles. In addition, the participants received few treatments of DN rather than just a single session.

4.5. Study limitations and future studies

The main limitations of this study are the small sample size and the fact that the examiner was not blinded to the intervention. Furthermore, we did not record the total number of needles (dose) used per treatment session and treated all patients six times without assessing the total number of treatments required for full pain relief.

It is also worth noting, that although using sham needling as a control group has advantages, it might stimulate C fibers in the skin and cause some analgesic effects or induce potential effects related to endogenous pain modulation in the brain [50].

Future studies should be conducted on larger samples and investigate the strength of GMe muscle and the impact of DN on strength, as well as its correlation with pain and function. Furthermore, a comparison of DN to back muscles, as opposed to other muscles (e.g. GMe and quadratus lumborum) should be conducted, and different needling techniques (e.g. superficial and deep needling, the fast in and out technique vs. keeping the needles in tissue for a longer time) should be compared.

5. Conclusions

The current study showed that adding DN of the GMe to physical therapy treatments for chronic low back pain improved pain level and function. We suggest that DN to the GMe may be an effective intervention, and clinicians may consider it as part of a multimodal management strategy to improve rehabilitation for nonspecific LBP patients. DN is a common technique within conventional treatments that can be suitable for most LBP patients.

Biographies

Gali Dar, PhD, PT. Prof. Dar is a full member of the Department of Physical Therapy at the Faculty of Social Welfare and Health Sciences at Haifa University, where she has served as the head of the department from 2019 to 2024. Her research focuses on the musculoskeletal system to better understand function, injuries, and treatment. Her main research areas are: orthopaedic and sports injury rehabilitation, pelvic floor muscle function, low back pain rehabilitation, sacroiliac joint and dry needling effect on muscle function, and musculoskeletal problems.

Alon Goldberg, M.Sc.PT, PT. is a musculoskeletal physiotherapist graduated from Zefat Academic College his Bachelor of Physical Therapy. He received his Master of Science degree in Physical Therapy from the University of Haifa in 2023. He works as a physical therapist in private and public clinics, treating orthopedic injuries and disorders

Funding Statement

The author(s) reported there is no funding associated with the work featured in this article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Ethical statement

This research was reviewed and approved by the institutional review board of the Faculty of Social Welfare & Health Sciences, University of Haifa, (#403/20). Informed consent was obtained from all participants.