Background and Purpose: Neck pain is widespread and stands as the sixth most common cause of disability globally. While laser therapy has been used for many years to treat non-specific neck pain (NNP), there is still a shortage of research directly comparing different laser modalities. The aim of this study was to evaluate and compare the therapeutic effectiveness of low-level laser therapy (LLLT) and high intensity laser therapy (HILT) in managing NNP.

Methods: sixty patients diagnosed with NNP were equally randomized into three groups. HILT group received 10 weeks of HILT, LLLT group received 10 weeks of LLLT and a control group that received a home program. Outcome measures were evaluated at baseline and after the intervention period and included pain intensity, neck disability, active cervical range of motion (ROM), and quality of life.

Study Design This study was designed as randomized comparative trial. The study procedures were conducted in the electrotherapy laboratory in the Department of Rehabilitation and Health Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia between March 2023 and April 2024. The study involved recruitment of 75 subjects from the university hospital and local clinics. Initial evaluation was performed by an orthopedist. The study sample included participants diagnosed with chronic non-specific neck pain (NNP) according to clinical and radiological tests. Study subjects were randomly assigned to one of three groups high intensity laser therapy (HILT) group, low-level laser therapy (LLLT) group, and a control group. The HILT group subjects underwent 10 weeks of HILT in addition to a home exercise program while the LLLT group subjects underwent 10 weeks of LLLT in addition to a home exercise program. The third group was a control group where group subjects performed only a home exercise program and did not receive laser therapy. The use of analgesics or nonsteroidal anti-inflammatory medications was not allowed during the intervention period (17).

The randomization process was conducted using SPSS statistical software, following a 1:1 allocation ratio and stratified by center, with random block sizes of four to ensure balanced distribution. An independent researcher, who was not involved in recruiting participants or delivering the interventions, generated the randomization sequence. Group assignments were recorded on numbered cards and sealed in opaque envelopes by this independent researcher. These envelopes were later opened by the intervention researchers, who administered the respective treatment according to group allocation.

Blinding was maintained throughout the study. All participants were unaware of their assigned group, ensuring subject blinding. Although the therapists delivering the treatments knew which group participants belonged to, they were blinded to the specific laser parameters, as these settings were predetermined by an independent researcher. The therapists' role was limited to implementing standardized treatment protocols without access to detailed device settings. Furthermore, all outcome evaluations were performed by an assessor who was blinded to group allocation, thereby minimizing assessment bias and maintaining the integrity of the study's double-blind design.

Inclusion Criteria:

• chonic neck pain lasting more than 30 days with no evidence of foraminal compression;
• age 18 years or older;
• experiencing considerable pain, stiffness, or discomfort localized to the neck area, without associated numbness or radiation of pain to the upper limbs;
• a visual analog scale (VAS) pain rating of 3 or above;
• no therapeutic intervention within the last month

Exclusion Criteria:

• Previous cervical spine trauma or surgery;
• significant cervical disc prolapse, cervical nerve root compression or spinal cord manifestations;
• history of severe and frequent migraines, fibromyalgia, shoulder diseases, rheumatic or rheumatoid diseases, severe osteoporosis, mental illnesses, significant spinal deformities, or serious cardiovascular, pulmonary, or neurological diseases.