Design
The present study was a parallel-group randomized controlled trial. Patients recruitment and data collection were conducted between December 2019 to April 2020.
Participants
Patients with neck pain were recruited from physiotherapy and orthopedic clinics under the supervision of the Shiraz University of Medical Science and selected by convenient sampling method. Potential participants were first assessed for eligibility by a physiotherapist. The inclusion criteria were: 1) women between 18 and 45 years old, 2) mechanical neck pain without referral signs lasting for at least 3 months, 3) the craniovertebral angle less than 49 degrees, 4) reporting pain on palpation of the diaphragm, and 5) usage of smartphone and computer for an average of 4 hours or more a day.
The exclusion criteria were: 1) Auditory or visual impairments., 2) Balance or any neurological impairments, 3) History of neck surgery, 4) History of any trauma or fracture to the cervical spine, clavicle, scapula, and ribs, 5) Inflammatory diseases such as rheumatoid arthritis, 6) A congenital deformity in the neck such as torticollis, 7) Respiratory disease and Zona, and 8) doing any regular exercise for the last 6 months.
Interventions
The intervention group received both the diaphragm myofascial release technique and an exercise program, while the control group only received the same exercise program.
To release the diaphragm, the patient was positioned in the supine position. The therapist stood at the head of the patient. The therapist made manual contact bilaterally under the costal cartilages of the lower ribs (7th to 10th ) with hypothenar regions of the hands and last three fingers. During the patient’s inspiration, the therapist was gently pulling the points of hands contacts toward the head and slightly laterally, while elevating the ribs simultaneously. During exhalation, the therapist deepened hand contacts towards the inner costal margins, (14). The release technique was performed once a week for four weeks; each technique lasted for 5 to 7 minutes (15). All release techniques were done by the same physiotherapist.
The exercise program included the strengthening of the deep cervical flexor and shoulder retractor muscles and also stretching of the pectoralis and cervical extensor muscles. Both groups received the exercise program 3 days a week for four weeks. The complete exercises for each muscle group in addition to the duration and repetition are listed in Table 1.
Table 1
| | Exercise | | Measures |
Strengthen Deep Cervical Flexors | | |
| | Lying chin tuck Lying chin tuck with head lift (4 s) | | 3 sets of 12 repetitions 3 sets of 12 repetitions |
Strengthen Shoulder Retractors | | |
| | Standing shoulder pull back with elastic Resistance shoulder pull back with weight (2 lb.) | | 3 sets of 12 repetitions 3 sets of 12 repetitions |
Stretch Cervical Extensors | | |
| | Chin drop | | 3 repetitions with 30-sec hold |
Stretch Pectoralis Muscle | | |
| | Bilateral Pectoral stretch | | 3 repetitions with 30-sec hold |
Outcomes
The data collection was done in two steps. The first step was before starting the treatment and the second step was one day after the end of the treatment period (4 weeks). The primary outcome was head posture measurement and the secondary outcomes were the extent of chest expansion and the level of functional disability.
Craniovertebral angle (CVA): CVA was measured to assess the head posture. It is the angle between the line connecting the middle point of the ear tragus to C7 and the horizontal line that passes through the C7 (Fig. 1). CVA shows the position of the head relative to the C7 vertebra, which in patients with FHP is less than 49 degrees; the lower measured angle shows severe FHP. To determine the exact place of the C7 spinous process, patients were asked to bend their neck forward. This bony landmark becomes prominent in this position and this region was checked in a relaxed neck position, too; then, a marker was attached there. In the present study, this angle was measured using photography from the left sagittal view. A digital camera with a 35–70 zoom lens was placed on a tripod and the lens aperture and the zoom were set to the F-stop8 and 70 mm, respectively. The center of the lens was 4 meters away from the individuals with the subject in approximately the center of the lens to reduce the lens error. To minimize the parallax error, the camera was positioned perpendicular to the ground and parallel with the subject’s pelvis. A set square was placed 90 degrees on the wall behind the subjects to determine the proper frame angle for camera placement. To ensure that the head does not rotate, a circular frame, parallel to the patient's eye, was attached to the wall in front of the patient’s eyes, and the patient was asked to look at it. The patient's neck and upper thoracic area was naked and was photographed from the same distance. The same conditions will apply to everyone taking photos. These configurations were adjusted for each subject. Participants were asked to stand straight and comfortable, with straight knees and half of their body weight on each foot, the hands hanging beside the body, shoulder-width legs apart, and looking forward eyes. Also, to capture their natural posture, they were asked to relax and not to keep their posture in an erected or straight position (16). After capturing, the photos were transferred to a laptop and the CVA angle was extracted by Image J software (https://imagej.nih.gov/ij/). High reliability was reported for CVA measurement in a previous study (16).
Chest expansion (CE) measurement: The patient was asked to put her hands on the head during the standing position. The starting point of a tape measure was placed on the xiphoid process and then wrapped around the chest. The assessor measured the circumference of the patient’s chest (at xiphoid level) after maximum possible inhalation and exhalation, respectively (17). The difference between these two values shows the amount of chest expansion. Mohan et Al. reported the reliability of this method as excellent (ICC > 0.85 and SEMs < 5%) (18).
Copenhagen Neck Function Disability Scale (CNFDS): CNFDS is a self-administered questionnaire developed to measure the level of functional disabilities due to neck pain. In this scale, 2 items measure pain intensity, 9 items evaluate disability daily activities, and 5 items measure social interactions and recreational activities. Three possible answers are considered for each item: Yes, Sometimes, and No. The total score ranges from 0 to 30. The higher the score, the greater the disability. The validity and reliability of the Persian version of CNFDS were checked by Ghasemi et Al. (Cronbach alpha = 0.92, Test-retest reliability = 0.86) (19).
Sample size
The sample size of the present study was calculated based on the CAV standard deviation from a previous study. Considering a power of 80%, a significance level of 0.05, and a 10% drop-out rate, the number of participants needed in each group was estimated to be 26.
Randomization
Eligible patients with neck pain were randomly divided into two groups (intervention and control) by the blocked-randomization method. Six blocks with the size of four were taken into account.
Blinding
Sequentially numbered opaque, sealed, and stapled envelopes (SNOSE) were used to conceal the allocation procedure from the examiner. The randomization process was done by a person different from the therapists and examiner. All interventions were done by an expert physiotherapist who was different from the examiner.
Statistical methods
The normal distribution of the dataset was tested by the Shapiro-Wilk test and all data followed a normal distribution. The Paired T-test was used to compare the values of pre- and post-treatment for each group. The mean differences between the values of pre-treatment and post-treatment were used for statistical analysis. Between-group comparison was done by Independent sample T-test. All statistical analyses were performed by SPSS software (version 21; SPSS, Inc., Chicago, IL) and the significance level of alpha was considered to be 0.05.