The Influence of Expectations on Post-needling Soreness and Pain Processing After Dry Needling Treatment
Condition: Placebo Effect; Pain Intensity; Disability; Dry Needling
MeSH terms: Pain
Study type: Interventional

Summary: 
      The general objective of the study is to determine the effectiveness on local mechanical
      hypoalgesia, pain intensity, disability and psychological variables of the deep dry needling
      technique on a latent trigger point of the upper trapezius muscle.

      The specific objective of the study is to observe the interaction between patient
      expectations and hypoalgesic effects in patients who will receive the same technique but with
      different explanations about it before punction and which could influence on the modulation
      of post-punction pain.
    

Detailed description: 
      Study design:

      A randomized, longitudinal, experimental, prospective, parallel and double-blind clinical
      trial was conducted, where both the study subject and the researcher performing the
      measurements do not know which treatment group they belong to.

      Participants The sample was composed of 42 healthy patients residing in the Community of
      Madrid, all of whom were recruited personally for the study. All of them will have 15
      incisions by dry needling in latent trigger point of the upper trapezium localized by
      palpation. All patients will read the information sheet explaining what the study will
      consist, as well as the informed consent form, which they will sign voluntarily beforehand.
      Patients were randomly assigned using GraphPad Software's QuickCals application (La Joya, CA,
      USA) to one of the 3 study groups.

      Each group will be given a different sentence: one group will be attempted to influence with
      positive expectation, another with neutral expectation, and yet another will be attempted to
      influence with negative expectation.

      Measurement instruments

      Measurement of the range of movement by means of an inclinometer. To measure the range of
      movement the patient will be seated in a chair; feet supported on the floor, triple flexion
      of lower limbs of 90º (hip, knee and foot), back well supported and straight, head straight
      and look at the horizon. The inclinometer will be positioned to measure flexion, extension,
      right and left tilt and right and left rotation. The inclinometer for CROM (cervical range of
      motion) is approved and validated in different studies.

      Measurement of pain threshold to pressure

      A digital algometer was used to measure mechanical hyperalgesia. The model used was the X®
      brand, consisting of a 1 cm2 cylindrical rubber attached to a pressure gauge. It is
      calibrated in kilograms (kg) and pounds. The scale expressed in kg/cm2 was used. All patients
      were familiarized with this test through a trial session. They were instructed to say STOP
      when the pressure sensation changed to painful. Three perpendicular measurements were made on
      an active or latent myofascial trigger point situated in upper trapezium muscle, the mean was
      calculated and the data were recorded for analysis. A rest period of 30 seconds was
      established between the measurements. A dermographic pencil was used to mark these points
      prior to measurement. The intra-assay reliability is high in the upper trapezius muscle (ICC
      = 0.94-0.97). The minimum detectable change (CMD) for considering the results as clinically
      relevant in the upper trapezius fibres has been shown to be between 0.45 kgf and 1.13 kgf.

      Procedural protocol

      Prior to the technique, the patient will be explained that the study seeks to observe if pain
      appears after the dry needling procedure. During the explanation, the desired expectation
      will be introduced:

        -  Group with positive expectation: "it is a very effective technique that achieves
           excellent results in the improvement of the cervical musculature"

        -  Group with neutral expectations: "It's a physical therapy technique used to treat neck
           pain and we're investigating its effects"

        -  Group with negative expectation: "this is a technique that will cause discomfort in the
           area of intervention of the cervical muscles after applying it ".
    

Intervention name(s): Dry Needling
Intervention type(s): Other
Intervention description(s): Deep dry needling procedure
All subjects received a deep dry neddling technique on a latent myofascial trigger point of the upper trapezius muscle by isolating it by a pincer grasp with the thumb and index finger. This myofascial trigger point was previously found following the diagnostic criteria described by Travell & Simons and Fernández-de-las-Peñas et al., and the deep dry needling intervention applied was based on the technique described by Hong.
The patients were placed in a prone position. Prior to the technique, the area was disinfected with an antiseptic solution. Fifteen incisions were made with a 0.26x40mm monofilament needle. The number of local twitch response made were noted. After removing the needle, at the end a soft compression was made with a cotton to reduce the possible appearance of bleeding.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Studio design:
A randomized, longitudinal, experimental, prospective, parallel and double-blind clinical trial will be carried out in which both the study subject and the researcher who made the measurements do not know which treatment group they belong to.
Participants The sample was composed of 42 healthy patients residing in the Community of Madrid, all of whom were personally recruited for the study. All of them will have 15 incisions with dry needles in the latent trigger point of the upper trapezium. All patients will read the information sheet that explains what the study will consist of, as well as the informed consent form, which they will voluntarily sign before the intervention.
Each group will be given a different sentence: one group will attempt to influence with a positive expectation, another with a neutral expectation, and yet another will attempt to influence with a negative expectation.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: placebo effect; Dry Needling; diffuse noxious inhibitory control; Myalgia