Effect of high-intensity laser therapy in patients with non-specific chronic neck pain: study protocol for a randomized controlled trial

BACKGROUND: Chronic non-specific neck pain (CNNP) is a prevalent musculoskeletal disorder known for its significant disability and economic burden, ranking second only to low back pain in musculoskeletal conditions. Physical therapy offers effective interventions for CNNP, including low-level laser therapy (LLLT). High-intensity laser therapy (HILT) is a recent treatment for musculoskeletal pain, but studies that support its use in CNNP are limited. The objective of this study is to assess the effect of high-intensity laser therapy on pain intensity in patients with CNNP, given the existing evidence on LLLT for this condition. METHODS: This is a 2-arm, randomized, placebo-controlled trial with blinded evaluators. The research will be carried out in the laboratory of physical agents at the Andrés Bello University, Campus Casona de las Condes. Eligible participants include the entire internal and external community associated with Andrés Bello University suffering from chronic non-specific NP. Participants will be stratified by sex (4 subgroups) and randomized into 2 study groups: group 1 (HILT and stretching exercises) and group 2 (sham HILT and stretching exercises). Treatments will be performed twice a week for 4 weeks with 3 assessments: before treatment (T0), at the end of treatment (T1), and 12 weeks after treatment (follow-up) (T2). The main outcomes will be pain intensity at rest, pain intensity at movement (active cervical movements: flexion, extension, right and left side bending, and right and left rotation), and pain pressure threshold (average obtained for six evaluation points). Secondary outcome measures will include neck range of motion in the sagittal, coronal, and transverse planes and neck disability. DISCUSSION: In this study, HILT’s effects on patients with non-specific NP will be compared to those of a sham laser intervention. This RCT will offer new evidence regarding the potential benefits of HILT in terms of pain intensity, range of movement, and disability in people suffering with non-specific NP. TRIAL REGISTRATION: ClinicalTrials.gov NCT05689788. January 19, 2023.