Focused Shockwave Therapy for Neck and Shoulder Myofascial Pain

Myofascial pain syndrome of the neck and shoulder is a common musculoskeletal paincondition characterized by painful and sensitive areas within tight bands of muscle,commonly referred to as myofascial trigger points. These trigger points frequently occurin the upper trapezius and levator scapulae muscles and may cause localized pain,referred pain, muscle stiffness, reduced neck movement, sleep disturbance, andlimitations in work and daily activities. Persistent symptoms may also contribute toaltered posture, reduced muscle performance, and decreased quality of life.Focused extracorporeal shockwave therapy is a noninvasive treatment that deliversacoustic energy to painful soft tissues. Proposed effects include improved localcirculation, modulation of pain‐related nerve signaling, reduction of abnormal muscletension, and stimulation of tissue repair. Second‐generation focused shockwave systemsuse piezoelectric technology to provide a stable and precisely focused energy field. Thistechnology may be particularly suitable for treating relatively superficial muscles, suchas the upper trapezius.Ultrasound imaging provides a noninvasive method for evaluating muscle structure andfunction. In addition to measuring resting muscle thickness, ultrasound can be used toassess changes in muscle thickness during different levels of contraction. Thesemeasurements may provide objective information regarding muscle function that cannot beobtained from pain questionnaires alone. In this study, ultrasound imaging will be usedonly as an outcome assessment tool and will not be used to guide the location ofshockwave treatment.This study is a pilot randomized controlled trial designed to evaluate the effectivenessof second‐generation focused extracorporeal shockwave therapy in adults with chronic neckand shoulder myofascial pain syndrome. Approximately 60 participants will be enrolled andrandomly assigned in a 1:1 ratio to either a focused shockwave therapy group or ahome‐based neck exercise group.Eligible participants will be adults older than 20 years who have had nonspecific neckand shoulder pain for at least 3 months. The pain must primarily arise from muscles andsoft tissues in the upper trapezius or levator scapulae region, as determined by aphysical medicine and rehabilitation physician. Participants must also have a NeckDisability Index score greater than 5 and must not have recently received painmedication, muscle relaxants, injections, physical therapy, or other related treatment.Individuals will be excluded if their neck or shoulder pain is primarily caused by aneurologic disorder, cervical radiculopathy, clinically significant cervical degenerativejoint disease, rheumatic disease, previous head or neck trauma, cervical spine surgery,or whiplash injury. Individuals with contraindications to shockwave therapy will also beexcluded. These contraindications include pregnancy, malignancy, bleeding disorders, useof anticoagulant medication, acute infection or inflammation at the treatment site, animplanted cardiac pacemaker or defibrillator, or another condition considered unsuitablefor shockwave therapy by the study physician.Participants assigned to the focused shockwave therapy group will receive treatment toclinically identified tight and painful regions of the upper trapezius and levatorscapulae muscles. Treatment will be administered once weekly for 3 consecutive weeksusing a second‐generation Richard Wolf PiezoWave focused shockwave system. Each sessionwill include approximately 3,000 shockwave pulses. The treatment depth will generally beset between 20 and 25 mm, the treatment frequency will be approximately 2 to 4 Hz, andthe energy level will begin at a lower setting and may be gradually increased accordingto the participant's clinical response and tolerance. Treatment will be performed by aqualified member of the rehabilitation team in a designated treatment area.Participants assigned to the control group will receive instruction in a standardizedhome‐based neck exercise program for 3 weeks. The program is intended to improve neckmobility, reduce muscle tightness, and maintain flexibility of the neck and shouldermuscles. It will include movements in cervical flexion, extension, right and leftrotation, right and left lateral flexion, and upper cervical rotation performed with theneck in a flexed position. Participants will receive initial instruction and correctionfrom a qualified physical therapist, together with written educational materials.Adherence and difficulties with the exercises may be monitored through telephone orin‐person follow‐up.Clinical assessments will be performed before the intervention, after completion of theintervention period, and at the scheduled follow‐up visit. The assessments will includeboth patient‐reported and objective measures.Pain intensity will be measured using the Visual Analogue Scale. Participants willindicate the intensity of their neck and shoulder pain on a 100‐mm line ranging from nopain to the worst imaginable pain.Neck‐related functional limitation will be evaluated using the Neck Disability Index.This questionnaire evaluates the effect of neck pain on areas such as personal care,lifting, reading, concentration, work, driving, sleep, and recreation. Higher scoresindicate greater disability.Pressure pain threshold will be measured using an electronic pressure algometer. Pressurewill be applied gradually to the identified painful area until the participant firstreports discomfort or pain. The measurement will be repeated, and the average value willbe used for analysis. A lower pressure pain threshold indicates greater local pressuresensitivity.Ultrasound imaging will be used to assess the upper trapezius muscle. Measurements willbe obtained with the participant seated in a standardized position. Muscle thickness willbe measured at the midpoint between the seventh cervical vertebra and the acromion.Ultrasound measurements will be obtained under three conditions: complete rest, ananti‐gravity shoulder contraction, and maximal voluntary contraction.The ultrasound outcomes will include resting muscle thickness and contraction‐relatedchanges in muscle thickness. The percentage change from rest to anti‐gravity contractionwill be used to reflect muscle activation during a low‐level functional contraction. Theadditional percentage increase from anti‐gravity contraction to maximal voluntarycontraction will be used to reflect the muscle's capacity to generate a strongercontraction.The primary objective of this study is to determine whether focused shockwave therapyprovides greater improvement in pain than a home‐based neck exercise program. Additionalobjectives are to compare changes in neck disability, pressure pain threshold, restingupper trapezius thickness, and ultrasound‐derived muscle contraction measures between thetwo groups. The study will also explore whether changes in ultrasound measurements areassociated with changes in pain intensity, pressure sensitivity, and neck‐relateddisability.Participant characteristics and study outcomes will be summarized using appropriatedescriptive statistics. Changes over time within each group and differences betweengroups will be examined using statistical methods appropriate for repeated measurements.Group‐by‐time interactions will be evaluated to determine whether the pattern ofimprovement differs between the focused shockwave therapy and exercise groups. If thedata do not meet the assumptions required for conventional parametric analyses,nonparametric methods or linear mixed models may be used. Correlation analyses will beperformed to evaluate relationships between clinical outcomes and ultrasoundmeasurements. Statistical significance will be assessed using a two‐sided significancelevel of 0.05.Adverse events and participant tolerance will be monitored throughout the interventionand follow‐up periods. Participants may withdraw from the study at any time withoutaffecting their usual medical care. All study data will be coded and stored securely toprotect participant confidentiality.