The Patient Expectation in Dry Needling and Analgesia
The Patient Expectation in Dry Needling and Analgesia
This study will evaluate placebo mechanisms related to dry needling(DN) trying to determinate
 whether an additive effect occurs when DN is provided with an instructional set known to
 enhance placebo analgesia. External manipulation of patient expectation for receiving DN will
 be performed, in a similar way as has been already done in studies investigating the
 influence of expectation on spinal manipulative therapy interventions. The main purpose of
 this study will be therefore to determine, for the first time, how subjects' expectation
 about the effect of DN influences the resultant hypoalgesia. Analgesic effects of DN will be
 assessed using the conditioned pain modulation (CPM) paradigm, which has not been previously
 evaluated in relation to DN.
Just before DN intervention, participants will receive a positive or a neutral expectation
 instructional set regarding effects of a DN technique on pain perception. This instructional
 set will be randomly allocated to each patient.

 Participants in the positive expectation group will be told that DN procedure: "is a very
 effective form of treatment used to treat neck-shoulder pain and it is expected to reduce
 your perception of pressure pain". Participants in the neutral expectation group will be told
 that DN procedure: "is a form of treatment used to treat neck-shoulder pain that has unknown
 effects on your perception of pressure pain".

 DN intervention An experienced and trained physical therapist will provide DN to all the
 subjects. This researcher will be blinded to the specific expectation instructional set the
 participant receives. Participants will receive one session of DN treatment for the active
 Myofascial Trigger Points(MTrP) located at the upper trapezius muscle. They will be placed in
 a prone position on the examination table. Solid filament needles of 0.30 mm diameter and 40
 mm length will be used. The needle will be inserted into the skin over the palpated MTrP
 using pincer palpation, and slowly advanced perpendicularly until it reaches the MTrP and a
 twitch response is elicited.
Inclusion Criteria:

 -  neck pain (≥3 months of duration)

 -  VAS of 4-5 of pain.

 -  Presence of at least one active MTrP located at the upper trapezius.

 Exclusion Criteria:

 -  Patients with previous cervical spine or shoulder surgery.

 -  Cervical spine radiculopathy or myelopathy.

 -  Systemic disease.

 -  Fibromyalgia.

 -  Pregnancy.

 -  Using sedative drugs.

 -  Needle phobia.

 -  Bleeding disorder.

 -  anticoagulant medication.

 -  Previous experience with DN for myofascial pain.

 -  Skin lesion and infection or inflammatory oedema at the MTrPs site