The goal of this interventional study is to determine how well dry-needling can treat pain in people with Myofascial Pain Syndrome. The main questions it aims to answer are:

• Does dry needling improve pain for people with a trigger point (a tender, tight spot in the muscle)?
• How well can Electrical Impedence Myography (EIM), Myofiber Threshold Tracking (TT), and Ultrasound (US) detect changes in the muscle related to dry needling treatment?

Researchers will compare dry needling to a placebo (a treatment that does not enter the trigger point) to see if dry needling works to treat Myofascial Pain Syndrome with trigger points in the trapezius muscle (the muscle that extends over the back of the neck and shoulders), as measured by these three outcome measures (EIM, US, TT).

Participants will:

• Visit the clinic twice: once to receive dry needling treatment, and once for a follow-up
• Have muscle measurements taken before treatment and at follow-up
• Have a daily survey to record the intensity of their pain

Pre-Screening:

Participants will be pre-screened to assess eligibility. The questionnaire can be completed on the phone, online in a survey, or in person. Medical records will also be reviewed. Eligible participants will schedule an on-site visit.

Study Visit #1:

In most cases the following sessions will occur on one day, unless due to scheduling conflicts separate sessions must be scheduled.

1. Eligibility & Screening: Baseline review of medical history and medication will be done to ensure eligibility. Informed consent will be taken from participants. Demographic data will be taken. This will take approximately one hour.

   The following baseline procedures will occur:

2. Trigger point will be identified in the trapezius muscle, and marked with a marker by a physician.

3. Electrical Impedance Myography (EIM) - a trained technician will apply several small sticky pads (electrodes) to different parts of the subject's muscle and a very tiny electrical current will be applied that they will not feel. Several measurements will be done their muscle. This will take approximately 10 minutes

4. Ultrasound (US) - a trained technician will apply a small amount of gel to the skin. They will hold a small hand-held device on the skin and will measure the muscle. The gel is easily cleaned off of the skin when the testing is complete. This will take approximately 20 minutes.

5. Threshold Tracking (TT) - TT tests how quickly muscle responds to stimulation. The muscle is stimulated using a small needle which is placed superficially in their trapezius muscle. The subject will feel a small needle prick which should be less uncomfortable than having blood drawn. Electrodes (small sticky pads) are placed a short distance from the needle over the muscle. When their muscle is stimulated with the needle, the time it takes for the muscle to react is measured by the electrodes. This procedure will last 30 minutes and creates a tingling feeling.

6. Algometry - a controlled pressure will be applied to the trigger point to measure pain response. This will take 5 minutes.

7. Questionnaires- Subjects will be asked to complete some brief questionnaires about their pain, mood, and sleep.

8. Dry needling treatment or sham procedure will be administered by a physician. This will take 5-10 minutes.

Home Period:

1. Subjects will be asked to re-apply the marker spot made at their first visit as it fades. This is so investigators can use the same spot for testing at the next visit.
2. A pain survey will be taken daily either online, by phone, or on paper.

Study Visit #2:

This visit will occur approximately two weeks after the intervention. It will take around 2 hours.

1. Imaging and testing measures including EIM, TT, US, and algometry will be performed.
2. Questionnaires taken at baseline, and two additional ones, will be administered.
3. Adverse events and pain medication regimens will be reviewed.

Inclusion Criteria:

• Ages 18-80
• Presence of active trigger points with involvement of upper trapezius
• Able to manage breakthrough pain with acetaminophen only, excluding stable doses of pain medications at time of enrollment, which can be continued

Exclusion Criteria:

• Multiple active trigger points in the trapezius muscle if physician assessment concludes that this may interfere with subject's ability to detect changes in pain improvement from trigger point therapy

• Presence of cervical radicular pain, superimposed neuromuscular disease or condition that, in the opinion of the investigator, could confound interpretation of the data acquired from trapezius.

• Fibromyalgia or other generalized pain condition

• Opioid usage in the past 3 months

• Active substance use disorder

• Not on a stable dose for at least two weeks prior to study enrollment or unwilling to maintain a stable dose for duration of the study of the following drugs:

  1. SSRIs, such as citalopram, escitalopram, fluoxetine, sertraline,
  2. SNRIs, such as duloxetine, milnacipran, and venlafaxine
  3. Tricyclic antidepressants, such as notritptyline, amitriptyline, and desipramine
  4. Alpha 2 delta ligands: pregabalin, gabapentin
  5. Specific anti-epileptics: topiramate, lamotrigine, oxcarbazepine, and phenytoin
  6. Other: quinidine, mexiletine, and dalfampridine

• Skin allergy or sensitivity that would preclude the use of adhesive electrodes

• Significant systemic or psychiatric illness that in the opinion of the site Investigator would interfere with the individual's ability to participate in the trial

• Anticoagulation (with coumadin, clopidogrel, or direct oral anticoagulants; aspirin acceptable)

• TrP needle-based therapy in the past six weeks of the TrP to be studied

• Body mass index > 35 kg/m2

• Other factor that in the opinion of the site investigator would interfere with the ability to perform the study procedures

A final, complete, cleaned, and coded study data set will be provided for public access including the appropriate data dictionaries and case report forms on the Vivli data repository platform.

The IPD will be available following completion of all planned analyses and manuscripts.

We will make the data and associated documentation available to a NIH HEAL Initiative approved Central Data Repository, such as Vivli.