Myofascial pain syndrome of the neck and shoulder is a common condition characterized by persistent muscle pain, tenderness, stiffness, and limitations in daily activities. Focused extracorporeal shockwave therapy is a noninvasive treatment that may reduce pain and improve muscle function. However, additional clinical evidence is needed regarding the effectiveness of second-generation focused shockwave therapy and whether ultrasound imaging can objectively detect changes in muscle function after treatment.
This pilot randomized controlled trial will enroll 60 adults with chronic neck and shoulder myofascial pain syndrome. Participants will be randomly assigned to either a focused shockwave therapy group or a home-based neck exercise group.
Participants in the focused shockwave therapy group will receive one treatment session per week for three consecutive weeks. Participants in the control group will perform a standardized home exercise program designed to improve neck mobility and reduce muscle tightness.
Assessments will be performed before the intervention, after the intervention, and at follow-up. Study outcomes will include pain intensity measured using the Visual Analogue Scale, neck-related disability measured using the Neck Disability Index, pressure pain threshold measured using an algometer, and upper trapezius muscle thickness and contraction-related changes measured using ultrasound imaging.
The primary objective is to determine whether focused shockwave therapy is more effective than a home-based neck exercise program in reducing pain and improving neck function. The study will also evaluate whether ultrasound-derived muscle measurements are associated with changes in pain, pressure sensitivity, and functional disability.
Adults older than 20 years.
Clinical diagnosis of nonspecific neck and shoulder pain primarily arising from muscles and soft tissues in the upper trapezius or levator scapulae region, as determined by a physical medicine and rehabilitation physician.
Neck and shoulder pain lasting for at least 3 months.
Neck Disability Index score greater than 5.
Neck or shoulder pain caused by a neurologic disorder, including cervical radiculopathy.
Clinical or imaging diagnosis of cervical degenerative joint disease.
History of a rheumatic disease, including rheumatoid arthritis or systemic lupus erythematosus.
History of head or neck trauma.
Parallel
Second-Generation Focused Extracorporeal Shockwave Therapy
DeviceSecond-generation focused extracorporeal shockwave therapy will be applied to clinically identified tight and painful regions of the upper trapezius and levator scapulae muscles. Treatment will be administered using the Richard Wolf PiezoWave system once weekly for 3 consecutive weeks. Each session will include approximately 3,000 shockwave pulses at a treatment depth of 20 to 25 mm and a frequency of 2 to 4 Hz. The treatment energy level will begin at level 4 and may be gradually increased to a maximum of level 15 according to the participant's clinical response and tolerance.
Home-Based Neck Exercise Program
BehavioralParticipants will perform a standardized home-based neck exercise program for 3 weeks. The program includes cervical flexion, extension, right and left rotation, right and left lateral flexion, and right and left upper cervical rotation performed with the neck in a flexed position. Each exercise will be performed for 20 repetitions per set, for 3 sets, 5 times per day. Participants will receive initial instruction and movement correction from a qualified physical therapist, together with written educational materials. Adherence and exercise-related difficulties will be monitored during the study.
Change in Neck and Shoulder Pain Intensity
Pain intensity will be assessed using a 100-mm Visual Analogue Scale. Participants will mark their current neck and shoulder pain on a horizontal line ranging from 0 mm, representing no pain, to 100 mm, representing the worst imaginable pain. Higher scores indicate greater pain intensity. Changes from baseline will be compared between the focused extracorporeal shockwave therapy group and the home-based neck exercise group.
Change in Pressure Pain Threshold
Pressure pain threshold will be measured using an electronic pressure algometer at the clinically identified painful region of the upper trapezius and levator scapulae muscles. Pressure will be gradually increased at approximately 5 newtons per second until the participant first reports discomfort or pain. Two measurements will be obtained and averaged. Higher values indicate lower pressure sensitivity and greater tolerance to mechanical pressure. Unit of Measure: N/cm²
Change in Neck-Related Disability
Neck-related disability will be assessed using the Neck Disability Index. The questionnaire contains 10 items evaluating pain intensity, personal care, lifting, reading, headaches, concentration, work, driving, sleeping, and recreation. Each item is scored from 0 to 5, producing a total score ranging from 0 to 50. Higher scores indicate greater neck-related disability.
Change in Resting Upper Trapezius Muscle Thickness
Resting upper trapezius muscle thickness will be measured using ultrasound imaging with the participant seated and the neck maintained in a neutral position. The measurement site will be the midpoint of the line between the seventh cervical vertebra and the acromion. Muscle thickness will be defined as the shortest perpendicular distance between the superficial and deep muscle fascia. Higher values indicate greater measured muscle thickness. Unit of Measure: Centimeters
Change in Upper Trapezius Thickness During Anti-Gravity Contraction
The percentage change in upper trapezius muscle thickness from rest to anti-gravity contraction will be calculated using ultrasound measurements. Anti-gravity contraction will be performed with the shoulder abducted to 90 degrees without additional external resistance. The outcome will be calculated as: \[(anti-gravity contraction thickness minus resting thickness) divided by resting thickness\] multiplied by 100. Higher positive values indicate a greater increase in muscle thickness during anti-gravity contraction. Unit of Measure: Percent (%)
Change in Upper Trapezius Thickness During Maximal Voluntary Contraction
The additional percentage increase in upper trapezius muscle thickness from anti-gravity contraction to maximal voluntary contraction will be calculated using ultrasound measurements. The outcome will be calculated as: \[(maximal voluntary contraction thickness minus anti-gravity contraction thickness) divided by anti-gravity contraction thickness\] multiplied by 100. Higher positive values indicate a greater increase in muscle thickness during maximal voluntary contraction. Unit of Measure: Percent (%)
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