Effect of post-isometric relaxation versus myofascial release therapy on pain, functional disability, rom and qol in the management of non-specific neck pain: a randomized controlled trial

Non-specific neck pain (NSNP) is the most common and the 4^th leading cause of musculoskeletal disorder worldwide. It is estimated that about 70% of the population experiences neck pain throughout the life, with an annual incidence of 15% to 50%0 [1]. It is seen more commonly in middle-aged females [2]. It has been well established that NSNP is not only the risk factor for developing severe spinal pathologies and functional disability but that it is also associated with decreasing the quality of life and productivity of workers [3].

According to the global burden of diseases, the statistical prevalence of neck pain shows Asia at 10.14%, Australia at 10.13%, the Caribbean at 9.7%, Central Asia at 9.8%, Central Europe at 9.9%, East Asia at 11.8%, Eastern Europe as 9.9%, Latin America s 10.12%, and Southeast Asia as 7.6% [4]. According to the global burden of disease in the Mediterranean region the point prevalence of neck pain was estimated as 34.31 per 1000 in Pakistan [5].

The NSNP is described as pain present in the anatomical region of the neck without radiating to the upper limbs. It is also defined as the pain in the posterior region of the neck from the superior nuchal line to the spine of the scapula and the side region down to the superior border of the clavicle and the suprasternal notch [6]. The International Association for the Study of Pain refers to the duration of pain symptoms i.e. acute pain defined as pain for less than 7 days, sub-acute pain less than three months, and chronic pain more than three months [7]. NSNP is associated with occupational and musculoskeletal factors including prolonged work hours, poor sedentary lifestyle, high workload and demands, inappropriate computer workstation designs, and desk-bound work position [8, 9]. These factors may lead to muscle spasm, decreased cervical mobility and functional limitation [10].

Conservative treatment approaches to treat NSNP include pharmacological treatments such as analgesics and muscle relaxants [11, 12]. However, the physical therapy consists of manual therapy (post isometric relaxation, myofascial release), exercise therapy (stretching, strengthening, stabilization, endurance training), thermotherapy, cryotherapy [13], laser therapy, infra-red therapy, electrotherapy including TENS and ultrasound [14], dry needling [15], acupuncture [16]. The Post isometric relaxation is a form of muscle energy technique (MET) in which the patient’s muscles are moved in a particular direction against the counterforce of the therapist, which is mediated by Golgi tendon organ (GTO) when the muscle contracts isometrically. The GTO activates and responds by reflex inhibition and contracting antagonist muscles (by submaximal contraction of the muscles followed by stretching of the same muscles). It is used in the management of various musculoskeletal conditions that work on the principles of restoring biomechanics and reducing the movement restriction and pain [17]. The Post isometric relaxation involves the peripheral and central modulating mechanism by activating the muscles and joint mechanoreceptors, like periaqueductal grey in the midbrain or non-opioids noradrenergic descending inhibitory pathways and serotonergic. Further, MET increase augments hypoalgesia and fluid drainage. Rhythmic muscle contraction increases lymph flow rates and blood flow, while the mechanical forces acting on fibroblast increase transcapillary blood flow and produce changes in interstitial connective tissue. MET application may desensitize peripheral nociceptors and reduces the pro-inflammatory cytokines [18] Myofascial release therapy is the soft tissue technique that involves the application of low load and long duration stretch applied through knuckles or elbows on the restricted fascia that is facilitated by detecting the restriction in fascia [19] It decreases pain, increases blood flow and lymphatic drainage, and relaxes the muscles because the slow movement in the contracted muscles stimulates the parasympathetic nervous system that produces the feeling of relaxation [20].

According to a systemic review by Thomas et al. [21], studies reporting effectiveness of MET as standard treatment or combination with other therapeutic exercise is limited, the studies suggested that MET has a good clinical effect in reducing pain and improving ROM. However further research using a robust methodology is needed to enhance treatment effects for the management of NSNP. Overall, there is a lack of high-quality evidence investigating the effectiveness and safety of MET to guide its use in the clinical management of NSNP. However, the high risk of bias and methodological shortcomings require caution in interpreting these results [22]. Therefore, this study was conducted to evaluate the effect of post isometric relaxation versus myofascial release therapy on pain, functional disability, ROM, and QoL in the management of NSNP. In this study, the best manual technique is used with the good outcome effects in the physical therapy practices. This study not only helps the physical therapist to upgrade their knowledge regarding the NSNP but also provides the basis to manage the problem with more effective therapy.

Analysis of the baseline characteristics revealed that both groups were homogenous in terms of age and gender, i.e. a total of 60 participants in this research study 30 in each group. Out of 60 patients, there were 20(33.3%) males and 40(66.7%) females with a mean age of 32.4(5.0) years. However, the baseline characteristic for both groups is presented in (Table 2).

In this study, the pain intensity on the visual analogue scale showed a significant group-by-time interaction (F = 6.113, p = 0.008, ηp2 = 0.095) with the PIR group indicating better pain reduction with mean VAS (1.3 ± 1.0) over time than those in MFR group (2.0 ± 1.2). The neck disability index also showed a significant group by time interaction (F = 8.844, p = 0.002, ηp2 = 0.132) with the PIR group indicating better improvement in mean NDI (1.4 ± 2.0) over time than those in MFR group (3.6 ± 3.4). (Table 3).

CROM shows statistically significant change within mean scores of both the PIR group (Extension, Right and Left rotation) and MFR group (Flexion, Right and Left side bending), while pairwise comparison between PIR and MFR groups shows statistical significance in cervical extension and left rotation. The active cervical extension showed a significant group-by-time interaction with (F = 5.716, p = 0.010, ηp2 = 0.090) with the PIR group indicating significantly better improvement in mean cervical extension ROM (43.4 ± 1.6) over time than those in MFR group (42.0 ± 2.7). Furthermore, the left rotation also showed a significant group-by-time interaction with (F = 5.378, p = 0.012, ηp2 = 0.085) with the PIR group indicating significantly better improvement in mean cervical rotation ROM (79.2 ± 2.2) over time than those in MFR group (76.5 ± 5.9). However, no significant group-by-time interaction was observed for CROM, as measured using cervical flexion, right side bending, left side bending, and right rotation. (Table 4).

WHOQOL-BREF-100 shows statistically significant change within all domains of QoL in both PIR and MFR groups, while pairwise comparison between PIR and MFR groups in the social domain of WHO quality of life brief-100 shows statistical significant group by time interaction (F = 4.796, p = 0.016, ηp2 = 0.076) with the PIR group indicating significantly better improvement with a mean score of the social domain (55.6 ± 18.0) over time than those in MFR group (64.5 ± 13.1)). However, no significant group-by-time interaction between groups was observed in the physical, psychological, and social domains. (Table 5).

The current single-blinded RCT was designed to evaluate the effect of post isometric relaxation vs. myofascial release therapy on pain, functional disability, ROM, and QoL in the management of non-specific neck pain. The results of this study revealed that PIR showed significant improvements in pain, disability, Cervical ROM, and QoL at the 2-week follow-up compared with those in the Myofascial group.

In the current study, within and between groups analyses of VAS showed significant relief of pain after 6 sessions of treatment application in both groups. However, the PIR group was shown to be superior in means scores to the MFR group statistically. The clinically significant result could be interpreted because the greater change in VAS scores within the PIR group than MFR is within the range of a minimal clinical important difference (MCID) of VAS-neck ranging from 4.6 to 21.4 [34]. The reduction of pain following application of PIR could be due to the inhibitory effects of Golgi tendon organs, which reduces the motor neuronal discharges, thereby causing relaxation of the musculotendinous unit by resetting its resting length and Pacinian corpuscle modification. These reflexes allow relaxation in musculotendinous unit tension and decreased pain perception [35]. The results of our study were in agreement with the study conducted to evaluate the effect of PIR on 30 patients diagnosed with mechanical NP showed that PIR has a significant effect in pain reduction and increasing ROM [36]. The current study was also in consistence with the finding of the study in which MET was compared with manual pressure release to treat mechanical neck pain on 45 females participants. The finding of the study shows statistically significant improvement in within group analysis of pain intensity, PPT, CROM and disability p < 0.05 in both groups. However, between group showed insignificant results p > 0.05 in MPR group, whereas MET shows marginal significance in only in pain intensity p < 0.05 [24].

Regarding the comparison between the experimental treatments, we found that disability, measured through NDI, showed statistically significant differences in the immediate effects in favour of the PIR group. In the short term, there were also statistically significant differences between the experimental groups, this suggests that PIR is faster in obtaining a decrease in cervical disability. According to a systematic review, it was concluded that NDI has an MDC of 10% and MCID of 14% [37]. According to the present study, the average change score of both groups exceeded MDC and MCID values (i.e. mean difference within the groups on NDI was PIR 18.7 and MFR 17.5). Therefore, the difference in improvement between groups was significant, the clinical importance was also certain when the interpretation was performed based on mean difference. this could be because the NDI assesses different aspects of neck pain which consists of pain intensity, and daily activities, suggesting that improvement in the score might be due to the reduction of pain. The results of this study were in line with the study conducted by Phadke et al. conducted an RCT on 60 individuals with NSNP, and indicated that 6 days of manual therapy including MET and static stretching along with strengthening exercise and hot pack causes a significant improvement on both groups. However, both VAS and NDI scores showed better improvement in the MET group as compared to the stretching group (p < 0.025) [23].

The comparison of CROM within both groups showed significant improvement in all six movements. However pairwise comparison between groups also showed equal improvement in both groups. For patients with NP, MCID value had a variation of 5 to 10⁰ [38]. In the present study the mean difference score in all CROM has reached that MCID value giving clinically significant result. PIR showed better improvement in (Extension, Right and Left rotation), this could be explained by the hypothesis suggested by Taylor et al. that a combination of contractions and stretches (as used in PIR) might be more effective in producing viscoelastic changes than passive stretching alone, because the greater forces produce increased viscoelastic change and passive extensibility [39]. However, the MFR group also showed improvement in (Flexion, Right and Left side bending), studies showed the increase in the ROM from MFR occur by improving joint hypo mobility and breaking the adhesion between the soft tissue by shearing the crosslink’s and remobilizing the fascia back into the gel-like structure [32] The results of the present study were in agreement with the study conducted by Gilani et al. They randomly divided 30 patients into two groups: Group 1 (n = 15) received ischemic compression (IC) in upper trapezius myofascial trigger points, and Group 2 (n = 15) received MET. According to this study, IC was more significantly effective (p ≤ 0.001) for reducing neck pain than MET. MET, in contrast, was more effective for improving range of motion (p ≤ 0.001) [40]. Another RCT conducted by huguet to evaluate the effect of myofascial release therapy on neck pain including 41 participants diagnosed with NSNP. The result of this stated that myofascial release could be a better than multimodal physical therapy program in improving pain and CROM [41]

Within the available literature and for our knowledge this is the first study which investigate the effect of PIR as compared to MFR by using WHO-BRIEF 100 scale to access the quality of life in NSNP patients. According to authors’ knowledge, no consensus is available regarding the MCID values of WHO BREF-100 in NP yet. However, a study on NSNP reported MCID as 1.80 for Physical domain, 1.68 for physiological domain, 2.48 for social relationship, and 1.68 environmental domain [42]. In this study, among the four domains of WHO-BRIEF 100 all domains had a clinical change of scores within groups with MCID. Only the social domain showed a statistically significant difference between groups with more clinical differences. Whereas, the study conducted by Rodrigues et al. on 59 patients observed that both therapeutic procedures manual therapy and myofascial release improves the QoL of patients with occupational mechanical NP by using SF 36. The manual therapy group showed significant changes only in the dimensions of physical functioning and bodily pain, whereas the myofascial group achieved significant improvements in both PCS and MCS (physical and mental component scores). This study's results were in contrast with the finding of the above study, as in our study PIR was shown to be statistically superior compared to MFR [43].

In addition, the study limitation is the absence of a long-term evaluation of the outcome. Other studies with larger follow-up periods along with control groups are needed to determine the long-term clinical benefit and to generalize the intervention results. The main strength of the study is the clear and understandable methodology for both of the treatment groups and secondly, this study was single-blinded RCT.

The study demonstrated both the manual therapy techniques were effective in alleviating NSNP. However, individuals with non-specific neck pain who received PIR showed an overall better outcome in terms of VAS, (cervical extension and rotation), NDI, and WHO QoL BREF 100 (Social domain) than those who received the MFR at 2 weeks.