Participants
The study was a randomized clinical trial (1:1 ratio) carried out in Kasturba Hospital (KH), Manipal, on patients referred to the physiotherapy department for the management of mechanical neck pain. Ethical approval was obtained from the Institutional Ethics Committee, and the trial was registered in the Clinical Trials Registry of India (CTRI; Registration number: 2018/04/013088). All the participants signed a written informed consent to participate in the study.
Inclusion criteria
Individuals with a primary complaint of acute or chronic neck pain between the age of 18 to 60 years were included. Neck pain was defined as ‘pain perceived along the posterior aspect of the neck, from superior nuchal line to the first thoracic vertebra, with the absence of any neurologic signs & specific pathologies.’ Neck pain individuals with moderate to severe pain intensity, i.e., ≥4/10 on a numeric pain rating scale (NPRS) with cervicothoracic junction dysfunction were included in the trial. For the assessment of CT junction dysfunction, passive accessory intervertebral movements (PAIVMs) were performed at each cervical and the T1 segments. The participants were positioned in prone, and the intervertebral movement was assessed by delivering posteroanterior pressure using the tips of both thumbs against the spinous process in an oscillatory manner. The amount of segmental mobility (normal, hypo, or hypermobile) and pain provocation were assessed. This method of identifying the symptomatic segment in the cervical spine was determined to have acceptable reliability [15]. Subjects with pain provocation and reduced mobility at the CT junction segment were included in the study.
Exclusion criteria
Patients were not considered eligible for inclusion if they reported a history of recent significant trauma, previous spine surgery, presence of any red flags, or pregnancy. Patients were excluded if neck pain was associated with cervical radiculopathy, whiplash injuries, severe headaches, cervical spine fracture, or vertebrobasilar insufficiency.
Randomization & blinding
The participants were randomized into either the cervicothoracic junction mobilization group or the thoracic manipulation group. The random allocation of the participants to the groups was carried out by another individual not involved in the study procedures and the allocation concealment was ensured by opening the sealed envelopes and revealing the group to which the participant has to be allocated. Block randomization was done with seven blocks of 6 participants (n = 42) involving a computer-generated random sequence. Individual paper slips with the random assignment (3 slips each for group A and group B) were prepared and placed in a separate opaque envelope for each block. The outcome assessor evaluating the baseline & post-intervention outcome measures was blind to the group allocation of the participants, and the intervening therapist was not aware of the baseline scores of the participants. However, blinding of the patients and the treatment provider to the intervention was not possible.
Outcome measures
The outcome assessor measured the cervical range of motion and neck pain intensity, before & 30 min after the intervention.
Cervical range of motion
The active ROM in the cervical spine was assessed with the Cervical Range of Motion (CROM) device. The CROM device is an instrument used across studies to measure ROM of the cervical spine, with good intra-rater reliability (0.7–0.9) & inter-rater reliability (0.8–0.87) [16] and excellent validity [17]. A minimal detectable change of 10° in the cervical rotation ROM was considered significant in the study [18, 19].
The cervical ROM measurements were performed with the participants sitting on a chair with back supported until the mid-thoracic level, with instructions to sit in an upright posture. CROM device along-with the magnetic neckpiece was appropriately placed on the participant’s head. A neutral head & neck position was established; to minimize variations in ROM that can arise due to head and neck postures. Participants were then instructed to perform active neck movements up to the point of pain provocation or until the maximum extent of the mobility. Participants were asked to perform flexion with chin tucked in, and the extension movement was started with the chin raise. Instructions were given to keep shoulders stationary, to avoid the thoracic spine movement. Manual stabilization of the contralateral shoulder was done by the outcome assessor during lateral flexion and rotation measurements. The ROM was recorded in degrees from the relevant inclinometer once the participant completed the range of motion. The dial of the inclinometer was manually adjusted to ‘zero’ before the participant performed the rotation movement [14, 15].
Pain intensity
The Numerical Rating Scale (NRS) was used to assess the self-reported pain intensity during the most painful neck movement. The participants were asked to rate the NRS score verbally after explaining to them that a score of zero equals ‘no pain,’ and the maximum score of 10 implies ‘unbearable pain.’ NRS was found to have fair to moderate test-retest reliability and satisfactory responsiveness in the mechanical neck pain population [20].
Interventions
In both the groups, the post graduate student (SJ) pursuing Master’s in orthopedic physiotherapy delivered the intervention supervised by the faculty (GB, YVR) with a combined experience of 20 years in orthopedic physiotherapy.
CT junction mobilization
The participants received direction-specific Maitland mobilization to the C7-T1 level, according to their primary movement restriction (for flexion-extension restriction- central PA glide, for rotation restrictions-unilateral PA glide). The therapist decided the grade of mobilization according to severity, intensity & nature of the patient’s pain. The mobilizations were delivered in the prone position, with the patient’s forehead supported on his palms. The duration of mobilization was 30-s bouts given for three sets. For central PA glide, a central pressure angled towards the participant’s head was given with overlapping thumbs of the therapist placed on the spinous process of C7. The therapist’s thumbs were placed on the posterior surface of the articular process to be mobilized (C7 on the side of restriction), and anteriorly directed oscillatory pressure was applied for unilateral PA mobilization [21].
Thoracic manipulation
Participants in this group received a high-velocity low amplitude (HVLA) thrust at the mid-thoracic spine (T3-T6). The level of manipulation was decided by hypo mobility assessed with PAIVM testing [22]. Thrust manipulation was delivered in the prone position, with the therapist’s hands over the zygapophyseal joints of the hypo mobile vertebra. A single HVLA was performed, and if the audible cavitation was not achieved, a second thrust was given at the same level. After the intervention in both the groups, the treatment provider interviewed the participants to identify any potential adverse effects of the intervention.
Statistical analysis
The sample size calculation was performed considering cervical ROM as the primary outcome measure and identified as 21 participants in each group. Based on the earlier reports [18, 19] on minimal detectable change (MDC) in cervical rotation range, a 10° between group post-intervention difference for the cervical rotation ROM and standard deviation of 10° (exceeding the value reported previously [18] was considered for the two-tailed sample size calculation at 80% power and level of significance as 0.05. As the study included acute neck pain participants, post treatment symptom exacerbation and a probable 30% dropout for post intervention outcome measurement was anticipated and the final sample size (n = 42) included the dropout rate. The data analysis was performed using SPSS version 16. The Kolmogorov-Smirnov test was used to assess the normality of the data. The comparison of post-intervention outcomes between the two groups was performed with a one-way ANCOVA test with baseline outcomes as the covariates, and the adjusted mean values were reported. The within-group changes in the outcome measures were compared using a paired t-test.