The Immediate Effects of Dry Needling Acupuncture on Pain Intensity and Pressure Pain Threshold in Patients With Myofascial Pain Syndrome of the Upper Trapezius

Myofascial pain syndrome (MPS) is a regional pain condition involving muscles, fascia, and surrounding soft tissues and is commonly associated with myofascial trigger points (MTrPs). The upper trapezius muscle is a frequent site of MTrPs and may be associated with neck and shoulder pain, muscle stiffness, and functional limitations.

Dry needling is a minimally invasive acupuncture technique that uses a sterile filiform needle without the administration of pharmacological substances. The needle is inserted into the identified myofascial trigger point with the aim of providing mechanical stimulation and inducing a local twitch response. These effects may contribute to the reduction of MTrP irritability and pain through mechanical and neurophysiological mechanisms.

This study is designed as a quasi-experimental study using a one-group pretest-posttest design. The study will be conducted at the Medical Acupuncture Clinic of RSUPN Persahabatan, Jakarta, from August to December 2026. The study will include adult participants aged 18-59 years with posterior neck and shoulder pain, a myofascial trigger point in the upper trapezius muscle, a baseline Numeric Rating Scale (NRS) score of 4-6, and a Pressure Pain Threshold (PPT) of ≤3 kg.

Eligible participants who provide written informed consent will undergo a single session of dry needling. The intervention will be performed by a medical acupuncture resident of the Faculty of Medicine, Universitas Indonesia, with competency level 3. A sterile acupuncture needle measuring 0.25 × 40 mm will be inserted into the identified myofascial trigger point of the upper trapezius muscle at a 90-degree angle to the skin surface in the superior-inferior direction. Fast-in and fast-out needle manipulation will be performed for a maximum of three times or until one local twitch response occurs. The needle will then be immediately removed without retention.

Pain intensity and pressure pain threshold will be assessed immediately before the intervention and at 30 minutes, 24 hours, and 72 hours after the intervention. Pain intensity will be measured using the Numeric Rating Scale (NRS), ranging from 0 to 10, with higher scores indicating greater pain intensity. Pressure pain threshold will be measured using an algometer at the identified anatomical site, and the value will be recorded at the point when the participant first reports a sensation of pain.

The primary outcomes of interest are changes in NRS and PPT from baseline following the dry needling intervention. The study will evaluate changes at 30 minutes, 24 hours, and 72 hours after treatment.

Participants will also be monitored for adverse effects associated with the procedure. Following the intervention, participants will receive instructions regarding post-procedure care, including avoiding massage of the treated area and heavy shoulder loading, performing stretching exercises, maintaining ergonomic posture, and using a cold compress if discomfort occurs.

Data will be analyzed using SPSS version 25.0. Numerical variables will be assessed for normality using the Shapiro-Wilk test. For normally distributed paired data, the paired t-test will be used, while the Wilcoxon signed-rank test will be used for non-normally distributed data. Statistical significance will be defined as p < 0.05.

• Dry Needling Acupuncture (Device): The procedures will be done once, and outcomes will be evaluated at 30 minutes, 24 hours, and 72 hours after treatment.

Primary outcomes

• Pain Intensity Measured by the Numeric Rating Scale (NRS) [baseline, 30 minutes, 24 hours, and 72 hours after treatment]: The Numeric Rating Scale (NRS) measures self-reported pain intensity. The NRS is an 11-point numerical scale ranging from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Participants select the number that best represents their pain intensity at the time of assessment. Higher scores indicate greater pain intensity. The outcome is the change in NRS pain intensity from baseline to immediately after the dry needling intervention.
• Change in Pressure Pain Threshold (PPT) of the Upper Trapezius Muscle [baseline, 30 minutes, 24 hours, and 72 hours after treatment]: Pressure Pain Threshold (PPT) is an objective measure of pressure pain sensitivity in deep muscular tissue. PPT is defined as the minimum amount of externally applied pressure at which a gradually increasing, non-painful pressure stimulus is first perceived as painful. PPT will be measured using a pressure algometer applied to the specified measurement point in the upper trapezius muscle. The pressure will be increased gradually until the participant reports the onset of pain. The pressure value at the onset of pain will be recorded. Higher PPT values indicate lower pressure pain sensitivity, whereas lower PPT values indicate greater pressure pain sensitivity. The outcome measure is the change in PPT from baseline to immediately after the dry needling intervention.

Sex: All, ages: 18 Years to 59 Years

Inclusion Criteria:

* Male or female participants aged 18-59 years with complaints of pain in the posterior neck and shoulder regions.
* Myofascial trigger points (MTrPs) identified on palpation of the upper trapezius muscle.
* Numeric Rating Scale (NRS) score of 4-6 and Pressure Pain Threshold (PPT) ≤ 3 kg
* Willingness to participate in the study until completion and to sign the informed consent form.

Exclusion Criteria:

* A previous diagnosis of cervical herniated nucleus pulposus (HNP).
* History of thread-embedding acupuncture therapy in the upper trapezius muscle within the past 6 months.
* History of dry needling (DN) and/or acupuncture therapy in the upper trapezius muscle within the past 1 week.
* History of taking analgesic and anti-inflammatory medications within the past 24 hours.
* Presence of a tumor, wound, or skin infection at the needling site.
* History of hypersensitivity reactions to previous acupuncture therapy (metal allergy, severe atopy, keloids, or other skin hypersensitivity).
* Presence of a blood disorder or use of anticoagulant medications (heparin and warfarin).
* Pregnant women.

• Medical Acupuncture Study Program FKUI, Principal investigator, Medical Acupuncture Study Program Faculty of Medicine Universitas Indonesia