Blinding and Previous Experiences of Dry Needling

Study Overview
=================
Brief Summary
-----------------
Dry needling (DN) is a treatment technique widely used in patients with various musculoskeletal health problems due to myofascial trigger points (MTrP). DN has shown to have positive effect on pain and function in patients with mechanical neck pain. These positive results are thought to be the consequence of specific neurophysiological and mechanical processes. Research has shown that DN induces 1) end plate inhibition, 2) reduction of inflammatory substances, 3) increase of blood flow and oxygen and 4) a reduction of nociceptive afferent activity. However, the exact working mechanisms underlying DN effects is still a topic of debate. This trial addresses one of the major methodological issues in needle testing,the effects of proper blinding. DN is a specific technique that is not easily be replaced by another comparable intervention. A sham needle with a blunt tip was created that simulates penetration into the skin without actually doing so. Research about a valid method for the control in needling studies is for this reason of particular relevance. A proper blinding technique is of importance to further the field of DN.

Detailed Description
-----------------
The objectives of this study are to analysize short-term effects on pain intensity and pressure pain sensitivity according to previous experience (blinding) in subjects with mechanical neck pain receiving real or sham-DN and to determine the success in masking DN versus sham DN in patients with mechanical neck pain based on prior experience with this technique.

Official Title
-----------------
Blinding of Dry Needling Technique Based on Previous Experiences: A Double-blinded Clinical Trial

Conditions
-----------------
Neck Pain

Intervention / Treatment
-----------------
* Device: Dry needling
* Device: Placebo needle


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Non-specific mechanical neck pain of at least 3 months of duration Between 18-60 years old At least one active trigger point in the upper trapezius muscle which referred pain reproduces the neck pain symptoms Exclusion Criteria: whiplash injury; previous cervical or thoracic surgery; cervical radiculopathy or myelopathy; diagnosis of fibromyalgia syndrome; having undergone physical therapy in the previous 6 months; fear to needles

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: DN group<br>The intervention group will receive real dry needling (DN) (fast in and fast out needling technique) in an active MTrP within upper trapezius muscle. | Device: Dry needling<br>* Real dry needling will be conducted according to Hong description, fast-in and fast-out interventions. The intervention will be applied until a total of four local twitch responses will be elicited<br>|
| Placebo Comparator: Placebo needle<br>The placebo group will receive sham needling in an active MTrP within the upper trapezius muscle. A sham needle will be used as placebo. This needle has a blunt tip and retractable handle that created the illusion of a needle penetrating the skin. | Device: Placebo needle<br>* Sham dry needling with be conducted with a sham needle (Steitberger's Park sham device (PSD). This needle has a blunt tip and retractable handle that created the illusion of a needle penetrating the skin. When this needle touches the skin, a pricking sensation will be created. However, when pressure will be increased, the shaft of the needle disappears into the handle creating a sensation on the patient.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Neck Pain Intensity between baseline and follow-up periods | The intensity of neck pain at rest and during active movement of the cervical spine in rotation will be assessed with a visual analogue scale (VAS). | Baseline, inmediately after and 1 week after intervention | 
| Identification (blinding) of the needling intervention | Participants will be asked directly after the intervention whether they thought they had received a real intervention or a sham. Answering categories were: 'yes' (real DN) or 'no' (sham DN). | Inmediately after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Pressure pain sensitivity between baseline and follow-up periods | Pressure pain thresholds (PPT) will be assessed at the upper trapezius muscle, spinous process of C7 and distant pain-free area of the lower extremity (heel) | Baseline, inmediately after and 1 week after intervention | 
| Changes in patients self-perceived improvement between baseline and follow-up periods | Patients self-perceived improvement will be assessed using a Global Rating of Change (GROC) consisting of a 15-point scale ranging from -7 (a very great deal worse) to +7 (a very great deal better). Descriptors of worsening or improving are assigned with values ranging from -1 to -7 and +1 to +7, respectively | Baseline and 1 week after intervention | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Dry needling, Placebo, Myofascial pain syndrome, Blinding