Effects of Conventional Physical Therapy with or without Strain Counterstrain in Patients with Trigger Points of Upper Trapezius; a Randomized Controlled Clinical Trial

Background: Non-specific neck pain has potential contributing factors. One of the factors being emphasized in the modern era is the Myofascial trigger points in the upper trapezius muscle. These could be treated by strain counterstrain method whose effectiveness needs to be evaluated. Hence, the objective of the study was to compare the effects of conventional Physical therapy with or without strain counterstrain in patients with trigger points of upper trapezius muscle. Patients and Methods It is randomized controlled clinical trial. 48 patients with treatment group A (24 patients) and control group B (24 patients). 1 Lecturer/ Clinical Instructor, Physical Therapy Department, Teaching Hospital, The University of Lahore 2 Assistant Professor, University institute of Physical Therapy, The University of Lahore 3 Senior Lecturer, University institute of Physical Therapy, The University of Lahore 4 Physiotherapist, Mayo Hospital, Lahore 5 Physiotherapist, Physical Therapy Department, Nabeel Hospital Date of Submission 11-04-2016 Date of Acceptance for Publication 23-07-2016 Conflict of Interest: None Funding Source: None


Introduction
Non-specific neck pain is placing large economic burden on health system which can result in severe disability. 1 A pilot survey in Pakistan on computer users showed that 27.7% had radiating and localized neck pain. 2 One of the sources of non-specific neck 192 pain is Myofascial trigger points (MTrPs), seen in the muscle and fascia. They are hypersensitive taut bands in skeletal muscle, painful when compressed and give specific pain patterns away from the source. 3 To identify the trigger points, an examiner uses palpation method with the help of pulp of thumb and index finger. A liniment can be used to liquefy the area and localize the trigger point. The MTrPs gives specific local twitch response when stimulated with dry needle, clinical signs of tenderness when palpated and/or decrease in range of motion (ROM) of the region. Myofascial trigger points need skills in identification of the point, background knowledge and clinical practice of the examiner. 4 From different treatment methods on the Myofascial trigger points, Strain counterstrainis one of the treatment approaches whose effectiveness need an evaluation on scientific grounds. It is an osteopathic technique used by physical therapists and osteopaths, defined as -the passive specific positioning of patient and affected region by the physical therapist for 90 seconds that would reduce the sensitivity of trigger point‖. 5 The specific positioning of the upper trapezius is ipsilateral side flexion, contralateral rotation, ipsilateral shoulder abduction and external rotation. The position is maintained for 90 seconds.
In the present prospect and knowledge found in some databases i.e. PUBMED, Google Scholar, CIN-HAL and DOAJ, there is hardly any study found in the region addressing the effectiveness of strain counterstrain compared with conventional physical therapy. In addition, preliminary data is not available to find out impact of conventional physical therapy (CT) with strain counterstrain (SCS) on mobility and pain intensity and functional disability in nonspecific neck pain patients with trigger points.

Patients and Methods
It is randomized controlled clinical trial.
Data was collected from Physical Therapy and Rehabilitation Clinic.
Sample size of 48 subjects (24 in each group) was taken using 5% level of significance and 95% power of test, two tails and effect size 1.1 6 using G*power 3.1.7 software and patients with non-specific neck pain patients having active Myofascial trigger points in upper trapezius muscle were included.
Informed consents were taken from the patients. For the randomization and concealment, the sequencing was generated randomly by the researcher with the help of a software online and simple (unrestricted) randomization was done. Also, according to the guidelines of Doig and Simpson, sequentially numbered, sealed, opaque envelopes were prepared. 7 Random allocation and concealment were maintained according to CONSORT Statement. 8 After including the patient into the study, the subject met the outcome assessor for the baseline measurements. After the measurements, the patient received a sealed envelope with the corresponding code no. and, met the researcher who then opened the envelope and provide the allocated treatment (either SCS with CT or CT only). The patient met the assessor again to get pre-treatment measurement on day 4th. Lastly, the patient came on the 7 th day for the final measurement and no treatment was given on that day. Treatment was given on day 1 st and day 4 th only.
There were two groups in the study named as group A (24 subjects) and group B (24 subjects). Group A received Conventional Physical therapy and Strain counterstrain for 1 week. Group B received conventional Physical therapy only for 1 week.
For SCS, The subjects were in a sitting position on the chair and upper extremities were relaxed. The therapist used ultrasound gel to liquefy the area and pincer palpation to localize the trigger point. Once MTrPs found, the researcher started applying pressure to the area until the sensation identified the Myofascial trigger point. The position of comfort for applying strain counterstrain technique was ipsilateral side flexion, contralateral rotation and slight ipsilateral upper limb abduction. This position was maintained for 90s. Finally, the subject was slowly placed into a neutral position.
For Conventional Physical therapy, range of motion exercises and advice (as described in literature) was administered to the patient. The general range of motion exercise plan and advice were taken from Chartered Society of Physiotherapy. 9 Data was collected through pre-designed proforma and then analyzed using the SPSS 21 statistical software. For quantitative data, descriptive statistics including mean ± standard deviation (S.D.) were calculated. The statistical differences between two groups were compared with the independent samples t-test. The difference within the group was calculated using the repeated measure ANOVA. The statistical significance was set at 5% and confidence level at 95%. Effect size was used to measure the magnitude of a treatment effect within the group between day 1 st and 7 th . A standard set of tests was used in this study i.e. Cervical Goniometer for Cervical range of motion measurement, Neck Disability Index (NDI) for measurement of disability due to neck pain and Visual Analogue Scale for pain intensity measurement which is a blank line of 100 mm. 1,10,11

Results
The mean age of the patients in strain counterstrain and conventional physical therapy (group A) was 26.9 ± 4.65 years and group B (conventional physical therapy) was 26.5 ± 5.7 yrs. There were 12 males and 12 females in group A and 13 males and 11 females in group B. Among 48 patients, 66.7% had unilateral and 33.3% had bilateral non-specific neck pain (Table 1). Baseline values in group A and B for VAS, NDI, cervical flexion, extension, rotation and side flexion have been given in table 1 with p > 0.05 representing both groups were similar at baseline. Table 2 presents betweengroup difference on day 4 th and day 7 th . On Side -Flexion 74.0 ± 7.9 70.50 ± 8.5 were seen. In cervical extension and rotation, only significant difference was seen from day 1 st to 7 th but insignificant results from day 1 st to 4 th day and day 4 th to 7 th day. For side flexion, p<0.05 found from day 1 st to 4 th day and day 1 st to 7 th day but p > 0.05 from day 4 th to 7 th day.
In group B, significant results (p < 0.05) were seen for all three days for VAS. For NDI, p > 0.05 for day 1 st to 4 th day and p < 0.05 for day 1 st to 7 th day and day 4 th to 7 th day were seen. For cervical flexion, extension and side flexion, insignificant results (p > 0.05) were seen for all days. In case of cervical rotation, insigni- ficant results were found from day 1 st to 4 th day and day 4 th to 7 th day but significant from day 1 st to 7 th day as seen .Effect size has been shown to explain the degree of improvement seen with treatment provided. The interpretation of effect size is considered as 0.2 is small but not trivial, 0.5 is medium and 0.8 is large effect size.

Discussion
The upper trapezius muscle plays an important role in the stability and mobility of the neck region. The formation of trigger points in upper trapezius gives rise to specific pain patterns either in the neck, shoulder and upper limbs. Furthermore, the trigger point development is supported by the hypothesis that some motor units remain excited after overuse or injury. These excited muscle fibers can be treated using the treatment method of Strain counterstrain described by Jones. In the present study, effect size of the treatment group A was large in the variables of VAS and NDI but moderate in other variables of ranges of motion compared to the control group B having mild effect size. Between group comparison had shown significant difference using p-value < 0.5 indicating the effectiveness of Strain counter strain along with conventional physical therapy. These results were consistent with the studies by Klein et al., Hou CR et al. and F. Okhovatian et al. that SCS may be an effective treatment for upper trapezius muscle. 1,12,13 Different studies measured its effectiveness either as a sole treatment or combination with other specific techniques i.e. muscle energy techniques, longitudinal stroking andischemic compression. 5,10 A study by F. Okhovatian et al. in 2012 on strain counterstrain conducted a Randomized trial, found strain counterstrain an effective treatment technique in reducing neck pain and improving pain threshold measured by VAS and pain pressure threshold instrument (PPT) respectively. 13 The results were consistent with the present study in case of VAS. Their study measured only three variables i.e. VAS, PPT and effect size but present study measured VAS, cervical range of motion, neck disability index and effect size. Effect size calculated in both studies found moderate to large effect size for VAS in group A compared to group B with mild effect size.
Pain pressure threshold instrument was not used by the researcher due to non-availability and cost. The diagnosis of trigger point in present study was based on a subjective method rather than any objective visualization tool. Recent advances used pressure algometer to measure specific pressure and magnetic resonance elastography to visualize trigger or tender point. [14][15][16] The physiologic mechanism of strain counterstrain is still practically unproven although theoretical clinical reasoning is present to explain its physiology. Strain counterstrain work by automatic resetting of the muscle spindle. 1 It changes tone and neuromuscular activity of the muscles. 6 Still, it might be possible that pain relief of the muscle was due to patient relaxation with breathing during treatment and consciousness.
The present study concludes that conventional physical therapy and strain counterstrain is moderately effective in reducing pain, functional disability and improving range of motion at cervical region than conventional physical therapy alone in patients with trigger point of upper trapezius. These results actively contribute to the growing body of knowledge and evidence in supporting the use of strain counterstrain as part of treatment of Myofascial trigger points.
The focus of the study was on the upper trapezius muscles. There are other muscles needed to be considered in the posterior neck region where trigger points can be developed in different fibers. Also, it is required to find out that these trigger points are in slow twitch or fast twitch fibers and what are the numbers of trigger or tender points in one or group of muscles.