How Dry Needling at the Neck Affects Shoulder Movement, Strength, Pain, and Shoulder Circulation

All participants are required to attend 1 on-site visit (\~ 1.25-1.5 hours) at the study site (TWU). The procedures of this research study are described in the following: 1. Administration of the Consent Form, Intake Form, and Questionnaires At the beginning of the on-site visit, one investigator, depending on the study site and availability of the investigators, will describe the study purpose/procedures as well as the risks/benefits associated with this study to each participant. Once the participant agrees to participate in this study, the participant will be asked to sign the written consent form. Next, the participant will complete an intake form (see below and Section 9) for their demographic information and the history of their neck-shoulder pain. Each participant also will complete 3 questionnaires: (1) Brief Pain Index (BPI), (2) Quick Disability of Arm, Shoulder, and Hand Questionnaire (QuickDASH), and (3) Central Sensitization Inventory (CSI). These forms will be delivered online via Google form, or on paper if the participant prefers. These 3 questionnaires will provide information on each participant's neck-shoulder pain, function level, and degree of central sensitization/segmental facilitation. The BPI (see Section 9) is a 9-item self-administered questionnaire used to evaluate the severity of a patient's pain and the impact of this pain on the patient's daily functioning. The QuickDash is a self-report questionnaire (see Section 9) used to determine how shoulder pain affects a patient's daily life and to assess the self-rated disability of patients with shoulder pain. The CSI consists of two parts: Part A is a 25-item self-report questionnaire designed to identify patients who have symptoms that may be related to central sensitization. Part B asks patients whether they have been diagnosed with 10 central sensitization syndromes, such as fibromyalgia, whiplash, and migraine. 2. Palpation Assessment for Presence of Tenderness During this palpation assessment, the participants will lie prone with their arms at their sides. The investigator will palpate for tender points at the following muscle groups innervated by C5-C6 to determine eligibility: (1) Cervical paraspinals at C5-6 segment, (2) rhomboids near the spine of the scapula, (3) supraspinatus muscle belly, (4) the middle of the infraspinatus muscle belly, (5) middle deltoid. A skin marker will be used to mark these 4 sites so that the investigator can assess the same locations during the re-assessments. 3. Pre-intervention Assessments After gathering the subjective information and confirming the eligibility of the participant, the 3 outcome measures will be collected. The outcome measures will be collected in the following order to minimize position changes that could impact blood flow: (1) blood flow parameters in prone, (2) Shoulder range of motion (ROM), (3) Shoulder external rotation strength in supine. \- Shoulder ROM Testing: ROM testing will be performed while the participant is lying supine with the shoulder at 90° abduction and 10° of horizontal abduction and elbow at 90°flexion. The center of rotation of the goniometer will be placed over the olecranon while one arm of the goniometer will be positioned along the length of the ulna, aligned with the ulnar styloid process. The other arm will be positioned perpendicular to the ground. For both measurements of internal and external rotation, scapular compensation will be monitored by using the thumb on the coracoid process and fingers along the spine of the scapula. Each measurement will be repeated twice with the average measurements used for data analysis. * Shoulder ER Strength: Shoulder external rotator strength will be tested with the subject lying supine with the involved shoulder in neutral rotation, 30° shoulder abduction, 90° elbow flexion, and full forearm pronation. The tester will hold a handheld dynamometer perpendicular to the dorsal side of the distal forearm just above the ulnar styloid process (MicroFET®2, Hoggan Scientific LLC, UT). The participant will be asked to hold that position while the tester pushes hard and attempts to break the participant's resistance. The peak force will be read directly from the handheld dynamometer. The shoulder external rotator strength will be tested twice with a minimum of a minute rest between the 2 trials. The average of the 2 trials will be used for data analysis. * Blood flow assessment: Each participant will remain in the same position for ultrasound imaging. The ultrasound transducer will be placed perpendicular to the infraspinous fossa to visualize arterioles or arteries of the suprascapular artery as it exits below the spine of the scapula approximately 1 inch below the acromion and to quantify the velocity of blood flow near the tender points of the infraspinatus determined by palpation during the eligibility screen. The location of the transducer will be outlined after initial placement to ensure consistent placement of the transducer between the testing sessions. The spectral Doppler waveforms will be analyzed to trace the velocities throughout the cardiac cycle. The peak systolic (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatile index (PI) will be calculated using software available on the device. On a Doppler waveform, the PSV corresponds to each "peak" within the spectral window, whereas the EDV corresponds to the point marked at the end of the cardiac cycle just prior to the systolic peak. These values will be used to calculate the RI with the formula RI = (PSV - EDV)/PSV and the PI with the formula PI = (PSV - EDV)/mean velocity, where mean velocity is the average flow velocity during the cardiac cycle. Three images will be taken, with the average used for data analysis. 4. Dry Needling Intervention Following the baseline testing, the PI (JB) or Co-PI (SWP) will perform the dry needling intervention. All three have more than 10 years of experience with dry needling. A sterile, disposable, solid filament needle (Seirin Corp., Shizuoka, Japan) will be inserted manually into the multifidus of C5-C6 on each side of the segment. Once the needle has been inserted, the needle will be pistoned in an up-and-down motion within the multifidus muscle at approximately 1Hz for 10 seconds. The needles will then be left in-situ for 5 minutes. Cadaveric and Ultrasonographic Validation of Needling Placement in the Cervical Multifidus Muscle - ScienceDirect 5. Post-intervention assessment The 4 outcome measures will be assessed in the following order to minimize position changes: (1) blood flow parameters in the prone, (2) shoulder range of motions, (3) the number of tender points in the prone position, and then (4) Shoulder ER strength in the supine position. Shoulder ER strength will be assessed 3 times: Immediately, 15 minutes, and 30 minutes after the intervention.