Nonspecific neck pain (NSNP) is one of the most common musculoskeletal problems treated by orthopedic physicians and physiotherapists. NSNP has an annual incidence rate of 38 to 73% and a lifetime prevalence of approximately 48%, leading to both economic and social problems.Due to increased disability-adjusted life-years from 17 million (95% confidence interval (CI): 11.4-23.7) in 1990 to 29 million (95% CI: 19.5-40.5) in 2016, Chronic neck pain is a common musculoskeletal disorder worldwide. No specific cause for neck symptoms assigned for most patients so it described as non-specific chronic neck pain (NSNP)

Although the exact relationship between posture and NSNP is unsettled, the posture of the cervical spine appears to influence dorsal neck muscle activity at rest and during movement. Additionally, the forward head posture associated with thoracic kyphosis indirectly affects cervical flexion and rotational range of motion (ROM) also sustained computer work and prolonged using smart phones often in positions that encourage a functional kyphosis, appears to modify neck posture, as well as scapular positioning and upper trapezius muscle activity. Besides that Ergonomic intervention, including adjustments of the workplace station and postural correction, have been demonstrated to be effective in reducing NP with some work conditions. In addition, modalities that used to correct sagittal alignment of the cervical spine proved statistical and clinically significant results related to pain, disability, and improved nerve function. That is accomplish cause and effect relationship between bad posture and neck symptoms. According to the systematic review of Anabela et al., about head posture assessment useful for neck patients or not? The answer, of course, was yes, but it must be considered in relation to the patient's symptoms and related functional problems. Harrison and his colleagues reported that posture abnormalities occurred in the head, ribs, and pelvis in three dimensions in the form of translations and rotational displacements. Therefore, we should consider three dimensional (3D)postural assessment and correction during the treatment of NSNP associated with significant posture problems of the head in relation to thoracic. Growing research about using mirror image traction during ambulatory exercise, which is prescribed specifically to help normalize the patient's neuromuscular dysfunction and postural deformation via reflecting the patient's posture across different planes, is more beneficial than a less personalized program. With these considerations in mind and to combine the findings of 3D postural assessment into the treatment program, we designed adjustable 3D posture corrective orthotic (PCO) to be worn by the patient for a short time. The device has the ability to reflect all transitional displacements and rotational movements of the head then ask the patient to make ambulatory exercise using a treadmill while the PCO holds the patient's reverse posture. To our knowledge, no randomized clinical trial (RCT) had evaluated the addition of a 3D adjustable PCO to usual care program and investigate its short- and moderate-term improvement effects on NSNP management outcomes (i.e., neck pain, neck disability and 3-dimensional posture parameters of the head). The primary aim of our study was to evaluate of conducting an RCT using neck disability index (NDI )and 3D posture parameters. The secondary aim was NPRS and Active CervicalROM. investigate the effect size of the addition of ambulatory mirror-image traction via the wearing of 3D adjustable PCO compared to control group interventions for neck pain, disability, and 3D posture parameters.

Inclusion Criteria:

• Male and female subjects with age from 17-40 years old.

• Neck pain with equal or greater than 3/10 on a The Numeric Pain Rating Scale (NPRS) and the pain lasted more than 3 months (chronic neck pain).

• Participants with neck disability at least score on neck disability index (NDI) was 5 from the total score 50.

• Participants were included if they had posture deviations by screening test using GPS

• Posture displacements:

  1. An anterior head translation more than 2.5 cm.
  2. Side shifting of the head in related to thoracic more than .5 cm.

Posture rotations:

1. Rotation of head more than or equal three degrees.

2. Side bending of the head more than or equal three degrees.

3. Flexion or extension position of the head, normal angle 18 degrees, if more than that degree, it is meaning extension in upper cervical and if less means flexion in upper cervical. Participants included if they had at least two posture deviations whatever displacements or rotations. We included more obvious degrees or displacement of head posture related to thoracic to avoid variability of measurement between people and the posture deviations could be appeared and examined by visual examination.

   • If subjects could be able to continue treatment for 10 weeks then for 3 months of follow up.
   • If Participants accepted and signed an informed consent form.

Exclusion Criteria:

• If Participant reported any of the following conditions: Neck pain associated with whiplash injuries, medical red flag history(such as a tumor, fracture, metabolic diseases, rheumatoid arthritis, and osteoporosis).

• Neck pain with cervical radiculopathy, neck pain associated with externalized cervical disc herniation.
• Fibromyalgia syndrome, to avoid the similarity of fibromyalgia with an NP diagnosis, a physician used the criteria for the clinical diagnosis of fibromyalgia according to the American College of Rheumatology.
• If the patient made surgery in the neck area before whatever the cause of operation.
• Neck pain accompanied by vertigo caused by vertebrobasilar insufficiency or accompanied by non-cervicogenic headaches.
• People were excluded if they were undergoing any type of pain treatment they have psychiatric disorders or other problems that contraindicate the use of the techniques in this study.
• If Participants reported any of the following conditions: (1) a history of cervical or facial trauma or surgery. (2) Congenital anomalies involving the spine (cervical, thoracic, lumbar). (3) Bony abnormalities such as scoliosis.(4) Any systemic arthritis. (5) Recurrent middle ear infections over the last5 years or any hearing impairment requiring the use of a hearing aid. (6)Persistent respiratory difficulties over the last 5 years that had necessitated absence from work, required long-term medication or interfered with daily activities. (7) Any visual impairment not corrected by glasses. (8) Any disorder of the central nervous system. (9) pregnancy or breastfeeding because these conditions affect head posture.
• Participants could be unable to attend a 10-week treatment program and follow-up as¬sessments after 3 months.