The Effect of Dry Needling Compared to Lumbar Spine Mobilization on Functional Disability in Patients with Nonspecific Chronic Low Back Pain: Study Protocol for a Randomized Controlled Trial

Abstract

Background:

Low back pain (LBP) is a socioeconomic burden worldwide and a major contributor to healthcare costs. Mobilization and dry needling (DN) are well-known treatments for LBP, and both of them, as a part of treatment, can relieve LBP. Due to the importance of choosing interventions with greater effects on patients’ recovery, in this study we intend to compare DN and lumbar spine mobilization, as complementary therapies in combination with routine physiotherapy in the treatment of patients with chronic nonspecific LBP (CNLBP).

Materials and Methods:

The study is a two-arm randomized, double-blind, double-dummy, controlled trial comparing DN to lumbar spine mobilization in individuals (n = 56; 18–45 years of age) with CNLBP. The experimental group will receive DN plus sham mobilization, and the control group will receive Maitland mobilization plus sham DN (eight treatment sessions in 4 weeks). The primary outcome is functional disability, and the secondary outcomes are pain, lumbar multifidus (LM) and quadratus lumborum (QL) function, lumbar range of motion (ROM), pain pressure threshold (PPT).

Results:

The results of this protocol study provide information on the comparison between the effects of two complementary therapies, DN and mobilization, in people with chronic nonspecific LBP.

Conclusion:

In this study, we intend to solve the methodological problems of the previous study in this field. The results of this study allow the therapist to choose an intervention that may have more therapeutic effects in combination with routine physiotherapy in the treatment of CNLBP.

Trial Registration:

1) ClinicalTrials.gov (NCT05214456) and 2) IRCT.ir (IRCT20210706051802N1).

INTRODUCTION

Nonspecific low back pain (LBP) is interpreted as pain between the twelfth rib and the gluteal fold[1] in which the pathoanatomical cause of the pain cannot be detected, and it accounts for 90% of the LBP.[2] It affects people of different ages and is a chief contributor to the disease burden globally.[1] LBP often becomes chronic, and if nonspecific LBP lasts more than 3 months, it is called chronic nonspecific LBP (CNLBP).[3]

Psychosocial factors (such as anxiety or maladaptive beliefs) affect clinical outcomes negatively in participants with LBP as they cause pain to aggravate[4,5] or last longer.[6] Consequently, these factors should be considered in treating participants with LBP.[7,8] Moreover, according to the guideline, non-pharmacological approaches, such as physiotherapy, are first-line treatments for LBP.[9] Different physiotherapy interventions for LBP, such as dry needling (DN) and manual therapy (MT), which includes spinal mobilization and manipulation, have been mentioned. Among these interventions, DN is used by physical therapists due to its proper performance in improving functional disability (FD) and reducing pain.[10] DN is a semi-invasive procedure, in which the needle is inserted through the muscle, into the myofascial trigger point (TrP), a hyperirritable spot in a taut band of a skeletal muscle, to deactivate it.[11] The development of a chronic LBP syndrome is usually accompanied by the finding of active myofascial TrPs.[12]

TrPs can cause pain, functional limitations, stiffness, hypersensitivity, decreased joint range of motion (ROM), and muscle weakness.[13] Consequently, DN can be effective in improving these symptoms by deactivating TrPs. To be more specific, DN can improve the contractile function (CF) of the muscles, by releasing and deactivating TrPs. DN is effective in LBP,[10] but the priority of DN over other treatments in LBP is unclear.[14]

Mobilization is another treatment, which is used in treating LBP and can indirectly affect TrP.[15] mobilization, which is a passive, low-speed, low-intensity, and non-thrust movement that occurs within or at the limit of the joint ROM.[16] In fact, in chronic LBP, muscle and joint problems are related disorders and it has been shown that reduced joint mobility can cause TrPs in the muscles attached to the joint, as well as TrPs in the muscles can reduce joint mobility. Improving dysfunction of the intervertebral joints using mobilization can have therapeutic effects on the TrPs in muscles innervating from the same segment to which mobilization is applied.[15] Therefore, mobilization can be used in the treatment of myofascial pain along with TrPs[17] and decrease its symptoms, including pain, functional limitations, hypersensitivity, decreased ROM, and muscle weakness. However, there is still much debate about its effectiveness compared with other treatments.

It has also been shown that, immediately after mobilization, the CF of the local muscles that are directly attached to the joint, such as lumbar multifidus (LM)[18] and quadratus lumborum (QL) muscles, change.[19,20] The function of QL[21] and LM[22] changes in chronic LBP. Active TrPs are most prevalent in QL in patients with CNLBP.[23] Moreover, QL and LM are two of the four most important muscles in the lumbar supporting the lumbar spine that, if disrupted, can lead to chronic LBP.[24] These two muscles are also the primary stabilizers of the spine and part of the local muscle group that plays an important role in spine neuromuscular disorders.[25,26] Therefore, considering the importance of the QL and LM in the stability of the spine, the effect of lumbar mobilization and DN of these muscles on their function will be assessed as a secondary outcome in this study.

To sum up, both DN and mobilization, as a part of the treatment, can relieve LBP[27,28] and both of the interventions can improve TrP symptoms, including pain, functional limitations, hypersensitivity, decreased joint ROM, and muscle weakness. Mobilization is a safe treatment for chronic LBP[29] and can also be indirectly effective in improving the symptoms caused by the presence of TrPs. DN can directly treat TrPs and is an invasive treatment. Hence, both interventions have advantages and disadvantages compared with each other. Studies have been conducted before to compare each of our treatments with their sham treatments (mobilization with sham mobilization[30] and also DN with sham DN[31,32] in LBP); thus, in this study, we aim to compare DN and mobilization with each other as complementary therapies. Until now, only one clinical trial study in 2019 has compared DN and mobilization, as an adjunctive therapy, in LBP.[33] According to the results of this study, no differences were found between the two groups in terms of impact on FD as the primary outcome, and pain, rate of recovery, pain pressure threshold (PPT), and extent of restrictions on activities as secondary outcomes. The aforementioned study had some limitations, including the lack of a sham or control group, which is important for reasons including the assessment of efficacy and safety of the treatment.[34] In this study, we will solve the methodological problem (lack of control or sham group) of the previous study by adding sham treatment. This study aimed to compare the effects of DN with mobilization as complementary therapies with 56 nonathlete adults with CNLBP with TrPs. In particular, the primary aim is to compare the effects of these two interventions on FD. The secondary aim is to compare the effect of DN and mobilization on outcomes, including pain, QL and LM CF (thickness change between rest and contraction), lumbar ROM, PPT, DN side effects, and patient adherence to treatment. We hypothesize that there will be a significant improvement in the experimental group (DN) compared with the control group (mobilization) in the primary outcome, which is functional disability.

MATERIALS AND METHODS

This study will be a randomized, two-arm, parallel-group, double-dummy, double-blind, controlled trial with a 1:1 allocation ratio. The total study structure is exhibited in Figure 1. The results of this study might be published in various journals. The whole study will be performed in the School of Rehabilitation Sciences of Iran University of Medical Science. The sample size required for this study will be obtained through patients who were previously diagnosed with LBP by a doctor and then were referred to the physiotherapy department of Hazrat-e Rasool Hospital. The method of sampling in this study will be simple, nonrandom, continuous, and purposive. In this study, we use a priori sample size estimation, which is based on the minimal clinically important difference (MCID). The sample size is estimated by using Stata software to compare the differences between the two groups, and it is based on a 2019 study by Griswold et al.[33] The data will be collected using non-probability sampling from the available community. Finally, the test power was set at 80%, and the type I error was set at 0.05. The MCID for the Oswestry Disability Index (ODI) is 10 points.[34] The sample size was determined by Stata 16.0 software using the sampsi command, which is detailed in Additional file d. According to the calculation, 23 people will be needed for each group, but with a possibility of 20% dropout, 28 people will be accepted into each group. In total, 56 patients with CNLBP will be recruited.

Figure 1.

The CONSORT flow chart of the study. Drop-outs unknown; ITT analysis planned, so analysis N equals allocation

In general, both groups will be treated for eight sessions over 4 weeks (treatment frequency: 2×/week). The number of treatment sessions is selected based on the average number of treatment sessions in a study conducted by Coulter et al.[29] After completing the baseline measurements, the participant’s depression (using Beck’s Depression Inventory II),[35] smoking,[36] and fear of movement (using the Tampa Scale for Kinesiophobia) will be measured. Based on the studies by Nassar[35] and Shiri,[36] depression and smoking can influence LBP as major confounders and thus affect the outcomes. The timing of data collection and intervention is detailed in Table 1.

Table 1.

Participant timeline

Timepoint**	Enrollment	Study period
		Allocation	Post-allocation								Close-out
	-t1	0	t 1 1	t 2 2	t 3 3	t 4 4	t 5 5	t 6 6	t 7 7	t 8 8	t 9 9
Enrollment:
Eligibility screen	X
Informed consent	X
Personal questionnaire	X
Allocation		X
Interventions:
First group
Second group
Assessments:
Tampa Scale for Kinesiophobia (TSK)	X
Beck Depression Inventory II (BDI-II)	X
Oswestry Disability Index (ODI)			X								X
Numerical Pain Rating Scale (NPRS)			X								X
Lumbar multifidus thickness change			X								X
Quadratus lumborum thickness change			X								X
Lumbar range of motion			X								X
Pain pressure threshold (PPT)			X								X
Dry needling side effects											X
Adherence											X

¹Saturday of the first week (first treatment session). ²Wednesday of the first week. ³Saturday of the second week. ⁴Wednesday of the second week. ⁵Saturday of the third week. ⁶Wednesday of the third week. ⁷Saturday of the fourth week. ⁸Wednesday of the fourth week (last treatment session). ⁹3 to 7 days after the last treatment session

The second outcome assessor Bahare Firouze (BF) will check whether the patients meet the eligibility criteria to enter the study or not. Individuals can be involved in the study after meeting all inclusion criteria including 1) nonathlete patients aged between 18 and 45 years; 2) having pain between the 12^th rib and gluteal fold, which has lasted more than 3 months[3]; 3) Numerical Pain Rating Scale (NPRS) 24-h average >2; 4) having TrPs in the QL and LM; 5) symptoms provocation with passive accessory intervertebral movements on at least one segment of the lumbar spine[33]; and 6) being able to write and read Persian.

The exclusion criteria are 1) complications that can influence the treatment procedure, such as infection and chronic illnesses (such as diabetes)[37]; 2) history of lumbar surgery[38]; 3) specific LBP (e.g. infection, tumor, osteoporosis, fracture, structural deformity, inflammatory disorder, radicular syndrome, or cauda equina syndrome)[39]; 4) long history of steroid use; 5) pregnancy; 6) unexplained weight loss during the last month (more than 10 lbs)[40]; and 7) needle phobia.[41]

On the first visit, the compliance of patients with the inclusion or exclusion criteria will be checked. If appropriate, they will be given the information they need to participate in the study. If they agree, they will sign the informed consent form and join the study consciously.

Patients will be randomly admitted to either the first or second group with a 1:1 allocation ratio by utilizing the permuted block randomization method (restricted randomization), which is made of blocks with different sizes and are created with numbers 1 and 2, which are the agents of the two interventional codes. After finishing random allocation, the random treatment list will be created by a third person, from outside the study, and be put in the forms of numbers 1 and 2 inside the sealed, sequentially numbered envelopes, which are opaque. Following the primary assessment of the participant by the assessor, the hospital’s secretary will give the numbered envelopes to the participant. Afterward, the participant will give the envelope to the care provider Hamideh Mirzaei Ashani (HM), and the care provider will do the treatment based on the envelope. The treatment will be performed for patients for free, and also, the care provider (HM) will call participants twice a week, a day before each treatment session, to motivate participants to do their daily home exercises and raise their adherence to the treatment. Additionally, the participant’s adherence will be measured as a secondary outcome in this study. In this study, the participants, data analysts, and outcome assessors will stay blinded to the intervention assignment. Prohibited interventions include (1) any specific intervention for LBP, which is performed by a health practitioner; (2) muscle relaxants; and (3) narcotics.

After the termination of the study, participants can be informed about their treatment group if they want. If a participant requests to leave the study for any reason or in the case of severe events and harm, the intervention will be terminated. In this study, adverse events of DN are considered secondary outcomes. If any adverse event happens following DN, it will be managed by the care provider (HM) and recorded as a secondary outcome based on the Boyce study.[42] The research team will compensate for all the major adverse events that occurred for the participants due to the study. If the participants do not want to stay in the study due to the adverse events, they can quit the trial.

Outcomes

The primary outcome is FD based on the ODI questionnaire. The key secondary outcome is pain intensity based on NPRS. The secondary outcomes include LM and QL muscles’ function based on ultrasound measurements, lumbar ROM by goniometer and PPT by algometer, DN side effects, and adherence to the treatment. Each outcome will be explained in what follows:

1. Functional disability: The Persian version of the ODI will be used to assess the disability degree, which is valid and reliable (Cronbach’s a = 0.75, Pearson’s correlation coefficients = -0.66).[43] This questionnaire contains 10 activities of daily living with a total of 50 scores. MCID for ODI is 10 points.[42]

2. Pain: Pain intensity will be determined using NPRS, which is a divided form of the visual analog scale that covers the entire range of pain, and patients score their pain from 0 to 10. Number 0 indicates the absence of pain, and number 10 indicates the most imaginable pain. The participant will show the average intensity of his/her pain over 24 hours.[33] MCID for NPRS is 2 scores.[42]

3. LM and QL muscles’ CF: QL and LM muscle function will be assessed by attaining thickness measurement during rest and submaximal contraction. Ultrasound B-mode image assessment of the QL and LM muscles will be attained using an Affiniti 70 ultrasound machine (Philips, Amsterdam, Netherlands) with a 5MHz curvilinear transducer. All ultrasound measurements will be performed by an experienced radiologist with more than 7 years of experience. To increase the accuracy, the muscle thickness will be measured three times and then the average of the measured values will be estimated. The use of ultrasound to assess changes in muscle function is a noninvasive, promising, and reliable method.[38] QL and LM muscles’ CF will be calculated utilizing the ensuing formula: [(thickness contraction – thickness rest)/thickness rest × 100].[44]

   • A)LM thickness measurement method: LM will be imaged bilaterally in the parasagittal section (longitudinally) to allow the zygapophysial joint to be observed at the fourth lumbar vertebra’s level.[18,45] The participant will lie on his/her back, with his/her head in the midline, and a pillow will be placed under the participant’s belly until the lumbar lordosis is reduced to less than 10 degrees (which will be checked using an inclinometer placed on the sacrum). The participant will be instructed to relax, and then, three images will be taken at rest. To measure muscle thickness during voluntary muscle contraction, the participant will lie on his/her back with their opposite upper limb lift a weight (which is determined by the participant’s mass: 1) Participant’s mass less than 68.2 kg = weight 0.68 kg, 2) participant’s mass between 68.2 and 90.9 kg = weight 0.9 kg, and 3) participant’s mass more than 90.9 kg = weight 1.36 kg) 5 cm above the bed, while their elbow flexed at 90 degrees and upper arm abducted to 120 degrees.[46] Participants will be instructed to hold their breath at the end of the exhalation (to reduce the effect of breathing on muscle thickness) and to hold the contraction for 3 seconds. Each participant practices this process three times before performing the main assessment. The muscle thickness will be measured using linear measurements from the tip of the zygapophysial joint to the inner edge of the upper border of the LM [Figure 2]. Measurements of the LM muscle are highly reliable (Intraclass Correlation Coefficient ICC: 0.97–0.99), responsive to change (Minimally Detectable Change MDC: 1.6–2.8 mm),[47] repeatable, and valid.[48]
   • B)QL thickness measurement method: To measure the thickness of the QL, the participant will lie on his side and the ultrasound convex probe will be placed transversely in the abdominal flank above the iliac crest. Then, the probe will be slightly tilted posteriorly until obtaining a sufficient image from QL. The participant will be instructed to relax, and then, three images will be taken at rest. To measure muscle thickness during voluntary muscle contraction, the participant will be asked to lift the pelvis with a weight of 0.5 kg on the ipsilateral leg. All of the images will be taken at the L3–L4 level [Figure 3].[49]

4. Lumbar ROM: A goniometer will be used to measure the lumbar flexion, extension, and lateral flexion. For measuring lumbar flexion or extension ROM, the participant will be asked to stand with his/her hands on the chest and feet shoulder-width apart. The location of the goniometer will be in line with the midaxillary line and at the level of the last rib. The goniometer axis will be along the midaxillary line at the level of the lowest rib, the fixed goniometer arm will be perpendicular to the ground, and the moving arm will be along the midaxillary line. The participant will be asked to keep his knees straight and bend forward or backward as far as possible, which shows lumbar flexion or extension ROM. To measure lumbar lateral flexion ROM, the participant will be asked to stand and place his hands next to his body. The goniometer axis will be located on the spinous process of the S1 vertebra, the fixed arm will be vertical to the floor, and the moving arm will be in the direction of the spinous process of the C7 vertebra. Then, the participant will be asked to bend to both sides (right or left) as far as possible, which shows lumbar right or left lateral flexion ROM (Additional file e).[50]

5. PPT: PPT will be measured using a digital algometer (Jtech Medical Commander, USA). The participant will lie on his/her back with his/her hands under his forehead. The algometer tip with a 1-cm-square cross section will be placed vertically on the most painful point of the QL and LM at each lumbar level, which is 1.5 cm outside the spinous process of the lumbar vertebrae and perpendicular to the muscle belly of the LM, on the painful side. To stimulate the participant’s pain, the pressure will gradually increase at a rate of approximately 5 N/s and the participant will be asked to announce the onset of pain. The exact location will also be noted for the next examination by algometer (in 3 days after the last treatment session). This process will be repeated three times, and the average will be calculated to reduce the variability (Additional file f).[38]

6. DN side effects: In this study, DN side effects will be assessed as a secondary outcome. This assessment will be conducted using the table provided in a study by Boyce.[51] In each treatment session, participants will be asked whether they have had DN side effects, including bleeding, bruising, pain during or after DN, aggravated symptoms, drowsiness, feeling faint, headache, and nausea.

7. Adherence: The participant’s adherence rate will be measured based on the ratio of the number of treatment sessions in which the participant will participate to the total number of treatment sessions.

Figure 2.

LM thickness measurement: (a) participant position, (b) probe position, (c) LM thickness during rest, and (d) LM thickness during contraction

Figure 3.

QL thickness measurement: (a) participant position, (b) probe position, (c) QL thickness during rest, and (d) QL thickness during contraction

Interventions

Both experimental and control groups will receive routine physiotherapy including low-power laser plus core stability training,[9] as detailed in Additional file a.

Experimental group: The treatments of this group will be DN and sham mobilization in addition to routine physiotherapy.

• A)DN: The method of LM and QL DN is inspired by Dommerholt et al.’s[11] (2018) method, which is detailed in Additional file b. The needles will be inserted into the muscles to obtain a local twitch response, which is a brisk contraction of the taut bands in skeletal muscle. This procedure will resume until no more local twitch responses occur in each treatment session. Afterward, the needles will be left in place for 20 minutes.
• B)Sham mobilization for the lumbar spine: Mobilization will be conducted on the spinous process of the lumbar vertebrae at the level of the skin surface (less than the first degree of the Maitland’s mobilization) using thumbs.

Control group: The treatments of this group will contain sham DN and mobilization plus routine physiotherapy.

A) Sham DN: It will be conducted in the place of QL and all of the LM muscles just like the actual method, but the needles will only penetrate the surface of the skin and then will be left in place for 20 minutes.[52] B) Maitland’s mobilization: For executing lumbar spine mobilization, Maitland’s anterior–posterior mobilization method will be used, which is explained in Additional file c.

Data management and confidentiality

The data obtained from the measurements will be manually recorded in the relevant paper forms, and the assessors will check them immediately, and illogical values will be corrected instantly by repeating the measurement. For the data that may have errors during measurement, including the measurement of muscles’ CF and PPT, the evaluation will be repeated three times to decrease the error rate. All data will be collected in folders that are encoded with the participant identification code. Participant information will not be disclosed outside the study without the participant’s permission. Results from this study will be published in a peer-reviewed journal and also be presented in a recognized national or international conference. For granting public access to this information, sending a reasonable email to the corresponding author Mohammadreza Pourahmadi (MP) will help an eligible investigator receive the required information.

Statistical methods

Statistical analyses will be performed on a personal laptop using Stata version 16 (StataCorp LLC). Analysis of covariance (ANCOVA) for each dependent variable, with the baseline outcomes’ baselines as covariates, will be used. Perceived FD will be compared with consensus standards for MCID. Ostelo et al.[42] considered the MCID for ODI as 10 points for patients with LBP. Effects sizes will be also measured using the Cohen d. The significance level used for statistical analysis will be two-sided with confidence intervals at the 95% level. There will be no interim analysis or plan for additional analysis in this study. The sample size has been raised from 46 to 56 (considering the 20% dropout); hence, the sample size and the data will not be less than the required data for both groups. As a result, the per-protocol analysis will be utilized in this study and the missing data will not be included in the analysis. The scientific director and principal investigator will be in charge of supervising protocol exactness and managing data during the research.

DISCUSSION

LBP is a major public health challenge worldwide. Non-pharmacological approaches, such as physiotherapy, are contemplated as the first line of treatments for LBP. Mobilization and DN are two common interventions that physiotherapists use to treat their patients. These two interventions have been shown to be effective in decreasing pain and FD in people with Chronic Low Back Pain (CLBP).[27,28] Also, studies have demonstrated that they can affect muscle function, lumbar ROM, and PPT.[11,15] Also, it has been shown that these two interventions, as complementary therapies, are effective in improving LBP patients’ symptoms.[27,28] Due to the importance of choosing interventions with greater effects on patients’ recovery, in this study we intend to compare DN and lumbar spine mobilization, as complementary therapies in combination with routine physiotherapy in the treatment of patients with CNLBP. This study has strengths, including having a double-dummy (with the benefit of having a sham), double-blinded design, and a priori sample size calculation. In addition, it will measure DN side effects and patient adherence to treatment as secondary outcomes. Nonetheless, long-term follow-up is not considered in this study, which can be its limitation.

Ethics approval and consent to participate

The study protocol was approved by the Research Ethics Committee at the Iran University of Medical Sciences (IR.IUMS.REC.1400.651).

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.