|Population||The population will comprise adult patients (≥ 18 years of age) of either gender with tension-type headache, cervicogenic headache, or migraine. Tension-type headache, cervicogenic headache, and migraine diagnoses must be based on the International Classification of Headache Disorders [ICHD-3 beta 2013  and its previous editions ICHD-2 2004 ] proposed by the International Headache Society. If no specified criteria were reported among the studies, the diagnosis must be based on discriminable and important characteristics of tension-type headache, cervicogenic headache, and migraine disorders, as confirmed by patients’ doctors. Important characteristics of tension-type headache include dull, aching, non-throbbing pain occurring in short episodes of variable duration or continuously (chronic form) that can be distributed unilaterally or bilaterally and referred to temporal, parietal, occipital, or frontal regions of the head without nausea, visual/auditory disturbances, or vomiting . Important characteristics of cervicogenic headache include unilateral headache with symptoms and signs of neck involvement, including impairment in cervical spine ROM and pain on palpation of the neck structures, especially on the upper cervical spine . However, patients with cervicogenic headache may have headache without neck pain . Finally, important characteristics of migraine attack include recurrent headache, unilateral pain, pulsating quality, moderate to severe intensity, in association with nausea and/or photophobia and phonophobia and is aggravated by physical activity . Studies in which children or adolescents were treated with dry needling technique will be excluded from this systematic review.|
|Intervention||Dry needling is a therapeutic procedure used in subjects with myofascial pain or motor dysfunction that comprises inserting thin filiform needle directly into the skin, subcutaneous tissues, fascia, and muscle, with the intent to deactivate TrPs without the use of an anesthetic . In this technique, the needle usually moves in vertical direction at approximately 1 Hz with or without rotations . Sometimes the needles may be left in place for approximately 20 min with or without manual stimulation . Simons et al.  mentioned that dry needling targeting TrPs can disrupt the dysfunctional neuromuscular activity in the muscles, decrease muscle tone, and normalize the neurochemical pathways of muscles. Because of the potential interchangeable use of terms ‘dry needling’ and ‘acupuncture’ in the literature [6, 38], both search terms will be used. To be eligible for the review, an explicit explanation of the dry needling intervention is required and needed to involve the insertion of fine needles precisely into identified TrPs with the aim of influencing headache intensity or frequency . Additionally, if in a study at least one local twitch response was obtained during a needling procedure, it will be considered as a dry needling technique. No restriction for dosage of dry needling, frequency of treatment sessions, duration of intervention, and time to outcome measure will be set. However, for an article to be included in this systematic review, it should have at least one session of dry needling for patients with tension-type headache, cervicogenic headache, or migraine. We will exclude acupuncture studies in which the fine needle was only inserted into acupoints on the neck, face, and head regions without obtaining at least one local twitch response. Furthermore, when dry needling is used combined with other treatment(s) in primary studies, at least 50% of the total treatment programme is required to be presented for inclusion.|
|Comparator||Other physical therapy/conservative interventions, different substances injections, pharmacological interventions, and sham or control group.|
The primary outcomes of this systematic review are pain and disability. These outcomes were selected as the primary outcomes, since pain and disability are considered common patient reported outcomes.|
Pain is defined as pain intensity, measured at the time point closest to the end of treatment . Pain intensity may be assessed with a continuous self-report scale (e.g., NPRS or VAS), a rating scale within a composite measure of pain (e.g., McGill Pain Questionnaire), or an ordinal scale with greater than six levels (we will treat such ordinal scales as continuous variables). We will not exclude studies that use other measurement tools.
Functional disability is defined as any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human . Functional disability may be measured with a continuous, self-report scale (e.g., FRI), a rating scale within a composite measure (e.g., social functioning scale in the Short Form-36), or an ordinal scale with greater than six levels (we will treat such ordinal scales as continuous variables). We will not exclude studies that use other measurement tools.
For articles to be included, they should have at least one of the primary outcomes of this study. In addition, the secondary outcomes are cervical spine ROM, frequency of headaches, health-related quality of life (e.g., Short Form-36), and TrPs tenderness. We will exclude any other clinical or health-related outcomes from this review.
|Study Design||Clinical trials with concurrent comparison group(s) as well as comparative observational studies published in peer-reviewed journals will be included in the present systematic review. Results obtained from other observational studies (i.e., cross-sectional and cohort studies without any comparison group(s)), opinion pieces, editorials, systematic reviews, narrative reviews, case reports, book chapters, policy documents, commercial documents, and websites will be excluded. Qualitative studies will not be included. Studies including tension-type headache and migraine patients with medication-overuse history according to the ICHD-3 beta criteria  will also be excluded. No restrictions for language of publication or geographic location will be applied. Articles published in a non-English language will be translated appropriately by Bing Microsoft Translator (https://www.bing.com/translator).|