High-intensity Laser Therapy for Neck Pain

Chronic nonspecific neck pain is a common musculoskeletal disorder recognized for its high rates of disability and economic losses, ranking second in musculoskeletal conditions after low back pain. There are several effective physical therapy interventions to treat chronic nonspecific neck pain, such as laser therapy. High-intensity laser therapy (HILT) is a recent treatment proposed to reduce musculoskeletal pain; however, there are few studies that prove its effects in reducing neck pain.The aim of this randomized clinical trial is to evaluate the effect of high-intensity laser therapy on pain intensity in patients with chronic nonspecific neck pain.The research will be carried out in the laboratory of physical agents at the Andrés Bello University, Campus Casona de las Condes. Participants will be employers and volunteer students with non-specific chronic neck pain. Participants will be randomized and allocated into 2 study groups: group 1 (HILT and stretching exercises) and group 2 (simulated HILT and stretching exercises). Treatments will be performed twice a week for 4 weeks with 3 assessments: before treatment, at the end of treatment, and 12 weeks after treatment (follow-up). The main results will be the differences in pain pressure threshold (ΔPPT), intensity of pain at rest (ΔRPI) and intensity of pain on movement (ΔMPI). Secondary outcome measures, on the other hand, will include differences in cervical spine range (ΔCROM) and cervical disability (ΔND).

Inclusion Criteria:Participants must be at least 18 years old.Both sexes (men and women)Non-specific, chronic neck pain, defined as pain or discomfort in the cervical region between the superior nuchal line and the spinous process of T1 or the shoulder girdle, with the following criteria: neck pain in the last 3 months or more; a questionnaire score of cervical disability (NDI) equal to or greater than 5; and cervical pain of 3 or greater on the numerical pain scale (NPRS).Exclusion Criteria:Neck or shoulder musculoskeletal injuries in the last 3 months (fractures, sprains, tendinopathies, dislocations, or muscle tears).Osteosynthesis materials close to the shoulders, neck, or surrounding areas.Wounds or skin changes in the shoulder and/or neck region (such as psoriasis, scars, or burns).Analgesic, anti-inflammatory, or muscle relaxant drugs for permanent use.Neurological alterations such as paresthesia, loss of sensation (partial or complete), decrease in strength, or color changes in the neck, arms, forearms, or hands.Diagnosed photosensitivity.Presence of solar urticaria or adverse reactions to sunlight.The presence of dermatomyositis, systemic lupus erythematosus, hepatic porphyria, cutaneous carcinoid syndrome, or pellagra.Cancer or tumors of some type have been diagnosed in the last 5 years.Epilepsy.