Myofascial Trigger Points therapy decreases myotonometric tone and stiffness of trapezius muscle, benefits headaches and muscle pain in migraine

2.1Subjects

Thirty-one right-handed female patients with episodic migraine without aura were recruited for the study (Table 1). The diagnosis of migraine was performed by a neurologist according to international criteria (beta ICHD-3) (Headache Classification Committee, 2018; IHS Classification ICHD - 3 Beta).

Inclusion criteria were: age - adults, gender - female, migraine lasting for at least 12 months diagnosed by a neurologist, no metabolic or cardiological syndromes, lack of neurological and orthopedic diseases in the area of the shoulder girdle and the cervical spine, voluntary consent to the examination in writing, and criteria according to ICHD-3 allowing to classify the symptoms as episodic migraine without aura.

Exclusion criteria were: age – under 18, gender – male, patients undergoing pharmacological treatment that cannot be discontinued, people with other headaches types, previous injuries of the musculoskeletal system in the cervical spine and cervical shoulder, skin diseases and other conditions such as deep vein thrombosis; criteria for excluding episodic migraine with aura.

The research was carried out in accordance with the Declaration of Helsinki (86/609/ECC) and the research protocol was approved by the Senate Research Ethics Committee at Jozef Pilsudski Academy of Physical Education in Warsaw (consent number: SKE 01-52 / 2017) and the Council of the Regional Center for Research and Development (RCRD) in Biala Podlaska (consent number: 14/21//10/11/2017). The study protocol has been registered as a clinical trial in the international clinical trials data base ClinicalTrials.gov (identifiter: NCT05646160).

2.2Experimental procedures

Patients suffering migraine without aura underwent a cycle of seven therapeutic sessions (encoded as Arabic numerals 1–6; as in the Fig. 1 and Table 2) of ischemic compression of myofascial trigger points (IC-MTrPs) therapy with a 3-day time intervals in between (Fig. 1). The whole therapeutic cycle lasted about 25 days, when counting from the 1’st to the 7’th IC-MTrPs therapy session (Fig. 1).

Fig. 1

Graphic time schedule of therapeutic and testing sessions with an indication of types of measurements collected during particular testing sessions. MYO –myotonometric measurent of upper trapezius muscle’s mechanical properties; PAIN –patients’ perception of shoulder girdle and neck muscles pain using the Visual Analogue Scale.

In each migraine patient the testing sessions were conducted in the following five time points (encoded as Roman numerals I–V; as in the Figs. 1, 3–6 and Table 2): I–pre-1’st therapy; II –post-1’st therapy; III –post-4’th therapy; IV –post-7’th therapy; V –one month after the 7’th therapy (1 month follow up) (Fig. 1). The myotonometric (MYO) measurements of muscle mechanical properties were performed in each of the five testing sessions: pre- and post-1’st, post-4’th, post-7’th therapy and 1 month follow up (i.e. while the testing sessions I–V; Fig. 1). Shoulder girdle and neck muscle pain was assessed during the following three testing sessions: post-1’st, post-4’th and post-7’th therapy (i.e. while the testing sessions II, III and IV; Fig. 1). Headache characteristics were evaluated twice, and namely while pre-1’st and post-7’th therapy (i.e. while the testing sessions I and IV; Fig. 1).

Fig. 3

Myotonometric frequency (F-MYO, [Hz]) values in the tested P1-P6 points at the left (A) and the right (B) side upper trapezius muscle. Data are expressed as mean (SD). * - statistically significant difference (p≤0.001) compared to the pre-1’st therapy measurement session value in the post hoc analysis.

Fig. 4

Myotonometric decrement (D-MYO, [log]) values in the tested P1-P6 points at the left (A) and right (B) side upper trapezius muscle. Data are expressed as mean (SD). No significant p > 0,005.

Fig. 5

Myotonometric stiffness (S-MYO, [N/m]) values in the tested P1-P6 points at the left (A) and right (B) side upper trapezius muscle. Data are expressed as mean (SD). * - statistically significant difference (p≤0.001) compared to the pre-1’st therapy measurement session value in the post hoc analysis.

Fig. 6

Shoulder girdle and neck (SGN) muscles pain felt by subject (assessed with VAS-visual analog scale score; [cm]) during therapeutic sessions. Data are expressed as mean (SD); # - statistically significant difference (p≤0.001) compared to the post-1’st therapy measurement session value in the post hoc analysis; ** - statistically significant difference (p≤0.001) compared to the post-4’th therapy measurement session value in the post hoc analysis.

2.3Therapeutic intervention - ischemic compression of myofascial trigger points (IC-MTrPs)

Therapeutic intervention relied on deactivation of MTrPs by ischemic compression method and was carried out according to the criteria established by Travell & Simons (2018). The IC-MTrPs therapy was applied on both sides of shoulder girdle and neck region on the following muscles: upper part of trapezius muscle, sternocleidomastoid muscle, temporal muscle, levator scapulae muscle, supraspinatus muscle, suboccipital muscle (Burstein, Jakubowski, & Rauch, 2011; Fernandez de Las Penas et al., 2010; Florencio et al., 2017).

IC-MTrPs intervention was made first on the right side and then on the left side and this order was the same in each patient. This is due to the fact that the right side showed palpatively higher muscle tone. A greater number of active MTrPs was found at the right side when compared to the left side (Fernandez de Las Penas et al., 2010). In physiotherapeutic practice, the principle of developing more tense tissues is applied in order to equalize tensions between the parties (Almeida Tolentino et al., 2021; Do et al., 2018; Espi-López et al., 2018; Fernandez De Las Penas et al. 2010).

Before starting the therapeutic procedure, the MTrPs localizations were identified by palpation and pinch pressure in patients lying back on the couch. During the procedure, a qualified physiotherapist sat behind the subject’s head. The pressure was sustained for about 5 seconds with a 2-3 seconds pause. In each subject, the intervention lasted 15 minutes on the same measurement day in the morning. During such a procedure, the patient could feel pain and discomfort in the area of pressure, however the pain decreased with time of the therapy. The manual pressure intervention were performed until the treated area was noticeably relaxed (based on therapist’s palpation) and the patient’s feeling of decreased pain (Do, Heldarskard, Kolding, Hvedstrup, & Schytz, 2018; Travell, Simons, & Simons, 2018). According to Travel & Simons (2018) when no results were obtained, the procedure was stopped after 2 minutes, and in the case of exacerbation of pain symptoms, it was stopped immediately. The strong pressure on the thumb induced local ischemia, as shown by local skin paleness. The cessation of pressure causes increased blood flow and better tissue nutrition.

The subjects underwent a cycle of seven IC-MTrPs therapeutic sessions, with 3 days breaks between each session, which lasted about 3 weeks in total (25 days) (Fig. 1). We chose the 7-session therapeutic program assuming that it would be effective enough since previous studies showed that 1-session therapy as well as longer therapeutic programs (ex. 12 sessions) were effective in MTrPs deactivation and pain alleviation (Moraska et al., 2017; Fernandez de Las Penas et al., 2011; Travell, Simons & Simons, 2018).

2.4Myotonometric measurements of muscle mechanical properties

Patients were seated steadily and relaxed in a chair with full body support, hands in lap, looking straight ahead. For all patients, six measurement points were carefully indicated on both sides of upper trapezius muscle, i.e. three points on the left upper trapezius (P1, P2, P3) and three on the right upper trapezius (P4, P5, P6) (Fig. 2). The three testing points were located on a horizontal line between the cervico-thoracic junction of the spine (C7 / Th1) and the shoulder process of scapula in a distance between these points similar for each patient. Going from medial to lateral side the testing points were as follows: (i) the most medial point as P1 on the left and P4 on the right trapezius, which was distant 3 cm laterally from the cervico-thoracic junction of the spine (C7 / Th1); (ii) the next P2 or P5 point (intermediate one) was distant 2 cm laterally from the P1 or P4; (iii) and the most laterally located the P3 or P6 point was distant 2 cm from the P2 or P5 (on the left or right trapezius, respectively) (Fig. 2). The testing points were carefully marked on a skin and kept (remarked) by patients at home during the time frame of the study (about 2 months) to ensure the myotonometric measurement in the same locations for all testing sessions. In the present study, we chose only the upper trapezius muscle to be measured since in our and others opinion (Kisilewicz et al., 2018; Kisilewicz et al., 2020), when taking into account an anatomical structure and location of upper part of trapezius muscle, a selective and reliable myotonometric measurements are easier to obtain for the upper part then for the middle or lower parts.

Fig. 2

Diagram indicating locations of the three testing points (P1, P2 and P3; as the grey dots) on the left side upper trapezius muscle, where the myotonometric measurements (using MyotonPRO^®) were conducted (own source). The three right side testing points (P4, P5 and P6) were located in similar manner on the right side upper trapezius muscle.

After instructions were given to the subject to relax, an investigator placed the testing end of the MyotonPRO^® device on the marked testing point of the upper trapezius muscle and performed myotonometric measurements using multiscan 10 mode (10 consecutive records from which an average values for the myotonometric parameters were automatically calculated). We used the multiscan 10 mode since according to Marusiak et al., (2018) the 10 or even 5 records mode enable an excellent repeatability for the resting-condition myotonometric measurements. Agreeing with methodological guidelines (Gapeyeva, & Vain, 2008) the testing end of the MyotonPRO^® device was placed in the testing point perpendicularly to the skin surface overlying the upper trapezius muscle. Myotonometric measurement’s order for the six strictly specified testing points was as follows: first P1, P2, P3 on the left side and then P4, P5, P6 on the right side. During each testing session, the whole myotonometric measurement protocol and testing conditions (temperature, light, time of the day) were identical. Myotonometric measurements were conducted by the same experienced investigator, who carried out the measurements without knowing about the measurement session number and did not participate in the analysis of the obtained data. We analyzed the following three myotonometric parameters: frequency of natural oscillations (F-MYO, [Hz]; reflecting non-neural muscle tone), decrement (D-MYO, [log]; informing about muscle elasticity) and stiffness (S-MYO, [N/m]; describing an ability of the muscle to resist an external force). The lower the F-MYO and S-MYO values, the smaller the tension and stiffness (respectively) of the examined muscle. The lower the D-MYO value the smaller the dissipation of mechanical energy during oscillation, indicating the higher the elasticity of the muscle structure (Stefaniak, Marusiak, & Bączkowicz, 2022). These parameters are more often reported in the literature and therefore their meaning for studying muscle mechanical properties is more acknowledged (Kisilewicz et al., 2018; Kisilewicz et al., 2020, Marusiak et al., 2018).

2.5Assessment of shoulder girdle and neck muscle pain using the Visual Analogue Scale (VAS)

Shoulder girdle and neck muscle pain was assessed with the graphic form of the Visual Analogue Scale (VAS), that consisted of a straight line (10 cm long) on paper with the endpoints defining extreme limits such as ‘no pain at all’ (number “0” in our study) and ‘pain as bad as it could be’ (number “10” in our study). First, the patient was asked: “How much did you feel shoulder girdle and neck muscles pain during the IC MTrPs therapy?". Then, the migraine patient was asked to mark with pen her perceived pain level on the line between the two endpoints. The distance between the two end points was measured with a ruler (Medline) to give a score of the patient’s perception of shoulder girdle and neck muscles pain, expressed in [cm]. Studies showed that an application of ruler in distance assessment increased the distance measurement reliability (Baker, Depuydt, & Thompson, 2009; Nemeth, Graham, & Harrison, 2003).

2.6Evaluation of headache characteristics

Headache characteristics were evaluated in each migraine patient before and after the 3-week IC MTrPs therapy. Average headache level while single episode was assessed using the same pain scale as it was described above in the point 2.5 (VAS score [cm]). Additionally, a frequency of headaches episodes (as number of headache episodes per month) and duration of single headache episode (as number of days) were reported by subjects in a custom-made questionnaire.

2.7Statistical analysis

The results are presented as arithmetic mean and standard deviation (mean (SD)) values for the whole tested group. Statistical differences between the testing sessions were analyzed using the repeated measures analysis of variance for Friedman ranks (due to absence of compliance with the normal distribution - Friedman ANOVA) and when a significant measurement session effect was found, post hoc for Friedman’s analysis was applied. For the inter-session comparisons of parameters measured during only two testing sessions (as in the case of headache parameters), a non-parametric test was used for two dependent samples: Wilcoxon pair wise order.

The results were considered statistically significant at the significance level of p≤0.05. We used the Statistica v. 10 software (StatSoft Inc., Krakow, Poland) for all statistical analyses.

3.1Inter-session comparisons of the myotonometric frequency (F-MYO) values in the tested points of the upper trapezius muscle

The F-MYO values, initially measured in the pre-1’st therapy session, had a clear tendency to decrease in all post therapy and 1-month follow up measurement sessions in all testing points of upper trapezius muscle (i.e. P1, P2, P3 on the left and P4, P5, P6 on the right side; Fig. 3A and 3B; respectively). However, the statistical analysis showed that compared to the pre-1’st therapy measurements the F-MYO values were significantly lower (P < 0.05) for the: (i) post-1’st therapy measurements in the left side testing point P3 (the most lateral point on the left side upper trapezius; Fig. 3A), (ii) post-4’th therapy measurements in all the three testing points on both sides of upper trapezius (i.e. P1, P2, P3 on the left and P4, P5, P6 on the right side; Fig. 3A and 3B; respectively), and (iii) 1-month follow up measurements in the left side testing point P1 (the most medial point on the left side upper trapezius; Fig. 3A) as well as in all the three right side testing points (i.e. P4, P5, P6; Fig. 3B).

3.2Inter-session comparisons of the myotonometric decrement (D-MYO) values in the tested points of the upper trapezius muscle

There was no clear tendency and any statistically significant inter-session differences (P > 0.05) in the D-MYO values in the left and right side testing points of the upper trapezius muscle (i.e. P1, P2, P3 and P4, P5, P6; Fig. 4A and 4B; respectively).

3.3Inter-session comparisons of the myotonometric stiffness (S-MYO) values in the tested points of the upper trapezius muscle

For the S-MYO measurements in the left and right side testing points of upper trapezius muscle (i.e. P1, P2, P3 and P4, P5, P6; respectively) there was a clear tendency of lower values in all post therapy and 1-month follow up measurement sessions, in reference to the pre-1’st therapy values (Fig. 5A, 5B). Nevertheless, the statistical analysis showed that compared to the pre-1’st therapy measurements the S-MYO values were significantly lower (P < 0.05) for the: (i) post-1’st therapy measurements in the left side testing point P3 (the most lateral point on the left side upper trapezius; Fig. 5A), (ii) post-4’th therapy measurements in all the three testing points on left side of upper trapezius (i.e. P1, P2, P3; Fig. 5A) and in the P4 and P6 testing points on the right side (the most medial and lateral points, respectively; Fig. 5B), and (iii) 1-month follow up measurements in the left side testing point P2 (the intermediate point on the left side upper trapezius; Fig. 5A), as well as in the P4 and P6 testing points on the right side (the most medial and lateral points, respectively; Fig. 5B).

3.4Inter-session comparisons of perceived shoulder girdle and neck muscles pain using the Visual Analogue Scale (VAS)

The initially measured VAS score for shoulder girdle and neck muscles pain in the post-1’st therapy session, significantly decreased (P < 0.05) in the post-4’th and post-7’th therapy session (Fig. 6). Also, there was a statistically significant decrease (P < 0.05) of the VAS value in the post-7’th compared to the post-4’th therapy session (Fig. 6).

3.5Inter-session comparisons of headache characteristics

All headache characteristics significantly improved (decrease of: average headache level while single episode, frequency of headache episodes and duration of single headache episode) in the post-7’th therapy session compared to the 1’st therapy session (P < 0.05; Table 2).

4.1Asssociation of MTrPs with migraine

Previous studies indicated that an occurrence of the MTrPs might be one of the reason that may contribute to start a migraine attack (Andreou, & Edvissone, 2019; Do, Heldarskard, Kolding, Hvedstrup, & Schytz, 2018; Sollmann et al., 2019). Additionally, several studies shown that patients with migraine have a greater number of MTrPs compared to healthy subjects and that higher number of MTrPs in neck and shoulder area correlates with muscular pain severity and duration of migraine attacks (Rezaeian, Mosallanezhad, Nourbakhsh, Ahmadi, & Nourozi, 2019; Travell, Simons, & Simons, 2018).

In contrary, studies by (Luedtke, Starke, & May, 2018; Rezaeian, Mosallanezhad, Nourbakhsh, Ahmadi, & Nourozi, 2019) reported that an inhibition of MTrPs in neck muscles (with usage of relaxation techniques including EMG biofeedback and dry needling technique) led to a decrease in frequency and severity of migraine attacks. The above mentioned study results are in agreement with our findings showing that ischemic compression therapy inactivate the MTrPs and consequently decreases headaches’ level, frequency and duration.

4.2IC-MTrPs therapy effects on the muscle hypertonia and pain

4.3IC-MTrPs therapy effects on the headaches’ characteristics

We assessed headache characteristics before and after 3-week period of the IC-MTrPs therapy and found a significant decrease of: (i) average headache level felt while single episode, (ii) frequency of headache episodes and (iii) duration of single headache episode. Our findings of positive effect of IC-MTrPs therapy on headaches characteristics might be caused by changed cervical spine biomechanics (associated with change in shoulder girdle and neck muscle tone) that might contribute to reduction of adverse tension in the spinal dura, that is assumed as one of the neurophysiological mechanism of headache (Alix, & Bates, 1999). This assumption is in accordance with studies by Crooks et al. (2018) and Espi-López et al. (2018), who found that soft tissue techniques and mobilization techniques may reduce headache in migraine patients.

4.4Implications and limitation of our findings, and perspectives for future research

Our findings confirm the assumption of beneficial cause-effect association between deactivation of trigger points via the IC-MTrPs therapy and an improvement of upper trapezius muscle functional state, and perceived shoulder girdle and neck muscles’ pain, with simultaneous reduction of headaches level, frequency and duration in migraine patients without aura. Findings of our uncontrolled study (case series repeated design) provide a preliminary evidence of the IC-MTrPs method’s efficacy in migraine pain therapeutic approach. This information is new and important not only from practical but also from scientific point of view. Based on our findings we can speculate about the mechanisms linking the IC-induced deactivation of MTrPs with positive changes of tonic muscle activity and consequent alleviation of muscle pain and headaches.

Unfortunately, the methodological limitations of our present study do not allow us to address some of scientific questions raised in our discussion, since we measured only the mechanical and behavioral counterparts of biochemical and neural processes that could stand behind the muscle state improvement and pain reduction in response to the IC-MTrPs therapy in migraine without aura. However, in spite of the above mentioned limitations, our current findings and considerations might be a good starting point for future controlled studies with more advanced methodology that will engage comprehensive multimodal measurements approach with using biochemical, neurophysiological and biomechanical methods.