Acupuncture for lumbar myofascial pain Protocol for a systematic review of randomized controlled trials

Abstract Background: Lumbar myofascial pain is a major contributor to chronic low back pain. Acupuncture has been applied as an effective treatment for chronic low back pain worldwide. However, few critical systematic reviews focus on the effect of acupuncture on chronic low back pain caused by lumbar myofascial pain have been published. The study aims to evaluate the current evidence on the efficacy of acupuncture for chronic low back pain caused by lumbar myofascial pain. Methods: A total of 7 databases will be searched from their inception to March 2019, including PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials, the Chinese National Knowledge Infrastructure database, the Chinese Biomedical database, and the Wanfang database. Randomized controlled trials (RCTs) that compared the effect of acupuncture for lumbar myofascial pain will be included. The primary outcomes will be reduction of lumbar myofascial pain assessed by Visual Analog Scale (VAS). Secondary outcomes are questionnaires to evaluate the effects of treatment on patients’ daily life activities and psychological status; and adverse events. The primary and secondary outcomes will be assessed before (0 day) treatment and at 0, 7, 30, and 90 days after treatment. Data synthesis will be computed by RevManV.5.3.5 software when a data-analysis is allowed. Methodological quality will be evaluated with the risk of bias according to Cochrane Handbook. Results: The results of this study will be published in a peer-reviewed journal. Conclusion: The study will provide evidence to illustrate acupuncture is an effective therapeutic intervention for chronic low back pain caused by lumbar myofascial pain. Trial registration number: PROSPERO CRD42019129735


Introduction
Lumbar myofascial pain (LMP) is one of the important contributor to chronic low back pain (CLBP) that is associated with lots of adverse consequences, such as reduced quality of life, fatigue, limitations in activity of daily life, waste of medical resources, bad mood, and even disability. [1][2][3] As the pain generator, myofascial trigger points (MTrPs) located in the corresponding lumber muscles are the pathological feature and treatment targets of LMP. [4] Managing the pain origin from MTrPs could decrease LMP and play a significant role in alleviating CLBP.

Methods
This review protocol has been registered on PROSPERO with number CRD42019129735 (http://www.crd.york.ac.uk/PROS PERO/display_record.php?ID=CRD42019129735). Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P) statement guidelines strictly comply in the protocol. [19] Any change of the review will be described if needed.
Ethics approval and patient consent are not required because this study is a protocol for a systematic review. The results of this study will be published in a peer-reviewed journal.
National Natural Science Foundation of China, No. 81574052.
The authors have no conflicts of interest.
2.1. Eligibility criteria 2.1.1. Types of study. All clinical randomized controlled trials (RCTs) that label acupuncture for CLBP caused by LMP will be included without any language or publication status restrictions. Quasi-randomized trials and trials that cannot be ascertained if the trial is truly randomized will be excluded. The primary and secondary outcomes were assessed before (0 day) treatment and at 0, 7, 30, and 90 days after treatment.

Search methods for the identification of studies
We will systematically search PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials, the Chinese National Knowledge Infrastructure database, the Chinese Biomedical database, and the Wanfang database from their inception to March 2019 without language restrictions. Search strategy of PubMed was as follows: "traditional acupuncture" or "manual acupuncture" or "electro-acupuncture" or "dry needle" and "lumbar myofascial pain" or "myofascial low back pain" or"lumber trigger points" or "low back myofascial trigger points" and"Randomized Controlled Trial" or "Randomized Controlled Trials as Topic" or "Controlled Clinical Trial", Pin Yin (including "Zhen Ci" or "Zhen Jiu" or "Hao Zhen" or "Dian Zhen" or "Gan Zhen" or "Shou Zhen" and "Yao Ji Jin Mo Yan" or "Yao Bei Ji Jin Mo Yan" or "Yao Ji Ban Ji Dian" in the title and keywords sections).
2.3. Data collection and analysis 2.3.1. Selection of studies. All the authors involved in this study had previous experience of completing systematic reviews. We will use EndNote X8 to manage citations from databases. The title and abstract of each citation retrieved will be checked by 2 independent reviewers (CYP and LXH) according to eligibility criteria. The full texts of potentially relevant studies will be retrieved for further assessment. Disagreements will be solved by discussion of a 3rd author (ZL). A table named "reasons for excluded studies" will be established for the excluded studies. Details of the selection procedure for studies are shown in a PRISMA flow chart (Fig. 1).

Data extraction and management.
We will use predefined extraction forms with detailed written instruction which will be created using Microsoft Excel 2017 to collect relevant information and data. The information will include first author, year of publication, sample size, participants, interventions, sites of MTrPs, outcomes, and adverse events. The results of the data extraction will be checked by a senior reviewer (ZL). When the data of articles are sufficient or ambiguous, we will contact the corresponding authors for more information by e-mail or telephone.

Risk of bias of included studies.
Two of reviewers independently used the Cochrane Handbooks version 5.1.017 for systematic reviews of intervention to assess the quality of included RCTs, [19] which includes 6 dimensions: adequate sequence generation, allocation concealment, blinding, the presence of incomplete data, selective reporting, other forms of bias. We will evaluate methodological quality as low, high, or unclear risk of bias.

Measures of treatment effect.
Outcome data were summarized using a risk ratio (RR) with 95% confidence intervals (CIs) for binary outcomes or mean differences (MDs) with a 95% CI for continuous outcomes.

Unit of analysis issue.
Considering that some studies compared 2 or more intervention groups with a control group, the research team followed the recommended advice in the Cochrane Handbook version 5.1.017 and combined groups to create a single pair wise comparison to avoid a unit-of-analysis error.
2.3.6. Dealing with missing data. We will try to contact the first author by e-mail or telephone to obtain the missing data if possible. If failed, we will analyze the available data and discuss the potential influence of the missing data in the discussion. When the I 2 value is <50%, Study will be regarded as no statistical heterogeneity if I 2 value is <50%, and the fixed-effect model will be selected. It will be considered significant heterogeneity while I 2 ≥ 50%, and we will select a random-effect model and make subgroup analysis to explore the potential causes of heterogeneity.

Data synthesis and analysis. Reviewer Manager
Software (RevMan 5.3.5) from Cochrane Collaboration was used for data synthesis and analysis. A random-effects will be used when I 2 ≥ 50%. When significant clinical heterogeneity existed, we will use subgroup analysis or sensitivity analysis, or only descriptive analysis.
2.3.9. Assessment of publication bias. A funnel plot analysis was conducted to determine publication bias if 10 or more studies are in the meta-analysis.

Subgroup analysis.
Subgroup analyses were performed for type of acupuncture if at least 2 trials were available for which I 2 > 50%.
2.3.11. Sensitivity analysis. Sensitivity analysis will be performed to identify the robustness of studies according to the following criteria: methodological quality, sample size, and missing data.
2.3.12. Quality of evidence. The quality of evidence for the primary outcomes will be assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE), [20] according to the comprehensive result of factors (risk of bias, inaccuracy, inconsistency, indirectness, publication bias) that influenced evidence quality which grades 4 levels: high level, moderate level, low level, and very low level.

Discussion
LMP, generated from MTrPs, is a major cause for CLBP. Disrupting MTrPs is the way to alleviate LMP and CLBP. [21] Acupuncture that targets MTrPs has been reported effective treatment for myofascial pain, [22,23] so this maybe a good choice for clinicians to use when they encountered a LMP patient with MTrPs. The therapeutic effect of acupuncture for CLBP caused by LMP has not been reported yet. Although a previous Cochrane review had assessed the effectiveness of dry needling of myofascial MTrPs associated with low back pain in 2017, however, dry needling just a small part of acupuncture science, [24] and there have been some new RCTs involving CLBP caused by LMP after 2017, so it is necessary to make a new review. We hope this systematic review will provide evidence that acupuncture is an effective method for CLBP caused by LMP

Author contributions
Yupei Chen and Xiaohong Li contributed to the conception of the study. The manuscript of the protocol was drafted by Yupei Chen and was revised by Li Zhang and Zejun Huo. The search strategy was developed by Jie Chen and run by Jing Xu, who will also independently screen the potential studies, extract data of included studies, assess the risk of bias, and finish data synthesis. Yupei Chen and Xiaohong Li will arbitrate the disagreements and ensure that no errors occur during the study. All authors have approved the publication of the protocol.