The Effects of Pressure Release, Phonophoresis of Hydrocortisone, and Ultrasound on Upper Trapezius Latent Myofascial Trigger Point

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1 72 ORIGINAL ARTICLE The Effects of Pressure Release, Phonophoresis of Hydrocortisone, and Ultrasound on Upper Trapezius Latent Myofascial Trigger Point Javad Sarrafzadeh, PhD, PT, Amir Ahmadi, PhD, PT, Marziyeh Yassin, MSc, PT ABSTRACT. Sarrafzadeh J, Ahmadi A, Yassin M. The effects of pressure release, phonophoresis of hydrocortisone, and ultrasound on upper trapezius latent myofascial trigger point. Arch Phys Med Rehabil 2012;93:72-7. Objective: To compare the effects of pressure release (PR), phonophoresis of hydrocortisone (PhH) 1%, and ultrasonic therapy (UT) in patients with an upper trapezius latent myofascial trigger point (MTP). Design: Repeated-measure design. Setting: A pain control medical clinic. Participants: Subjects (N 60; mean SD age, y) with a diagnosis of upper trapezius MTP participated in this study. Subjects were randomly divided into 4 groups: PR, PhH, UT, and control (15 in each group). All patients had a latent MTP in the upper trapezius muscle. Interventions: PR, PhH, UT. Main Outcome Measures: Subjective pain intensity, pain pressure threshold (PPT), and active cervical lateral flexion range of motion were assessed in 6 sessions. Results: All 3 treatment groups showed decreases in pain and PPT and an increase in cervical lateral flexion range of motion (P.001) compared with the control group. Both PhH and PR techniques showed more significant therapeutic effects than UT (P.001). Conclusions: Our results indicate that all 3 treatments used in this study were effective for treating MTP. According to this study, PhH is suggested as a new method effective for the treatment of MTP. Key Words: Myofascial pain syndromes; Pain; Phonophoresis; Rehabilitation; Ultrasonic therapy by the American Congress of Rehabilitation Medicine MYOFASCIAL TRIGGER POINT (MTP) is a hyperirritable nodule of spot tenderness in a palpable taut band of skeletal muscle that can refer pain to a distant point and also causes distant motor and autonomic effects. 1,2 MTP prevalence varies from 21% of patients presenting to a general orthopedic clinic to up to 93% seen in specialty pain management centers. 3 The exact cause of MTP is still unknown, but Simons et al 2 hypothesized that some muscle fibers shorten and form taut bands in response to the release of calcium ions from damaged fibers or excessive amounts of acetylcholine from the motor end plate. The upper trapezius is probably the muscle most often beset by MTP, 4,5 and Fischer 6 indicated that the upper trapezius is the most sensitive of 8 different muscles (upper trapezius, pectoralis major, levator scapulae, teres major, supraspinatus, gluteus medius, infraspinatus, paraspinals) to the pressure of an algometer. 6 MTP is classified clinically as latent and active, 7-9 and the spontaneous presence of the typical referred pain pattern and/or patient recognition of the referred pain as familiar can be a measure to differentiate latent versus active MTP. 2,10 Latent MTP also is introduced as a reason for activity pattern disorders A number of treatments are available for MTP in the 2 categories of invasive and noninvasive techniques. Some invasive techniques consist of injection therapy and dry needling, whereas noninvasive approaches include massage, stretching, and ultrasound. 2,3,14-18 Phonophoresis is a therapeutic method that may be helpful for the treatment of MTP. However, there is little information about the mechanisms of this technique. 19 Despite the lack of evidence for the effectiveness of phonophoresis, the impact of pressure release (PR) has been made crystal clear in numerous studies. 7,15,20-24 For this reason, we decided to compare phonophoresis of hydrocortisone (PhH) with PR. In addition, to determine the pure effects of ultrasonic therapy (UT) and algometery, 2 independent groups (UT, control) also were added to this study. The aim of the present study was to investigate the effect of PR, PhH, and UT on pain intensity, pain pressure threshold (PPT), and active cervical lateral flexion range of motion in latent MTP of the upper trapezius muscles. METHODS A convenience sample of 60 women who were identified with 1 MTP available in the upper trapezius muscle during the last 3 months to 1 year were recruited. Because the existence of numerous MTPs may affect the outcome, 25 we selected subjects with at least 1 MTP in the upper trapezius. Anthropometric characteristics of subjects are listed in table 1. List of Abbreviations From the Tehran University of Medical Sciences, Tehran, Iran. Supported by Tehran University of Medical Sciences. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated. Reprint requests to Amir Ahmadi, PhD, PT, Faculty of Rehabilitation, Tehran University of Medical Sciences, PO Box , Tehran, Iran, amirahmadi@tums.ac.ir /12/ $36.00/0 doi: /j.apmr ANOVA CLF ILF K-S MTP PhH PPT PR UT VAS analysis of variance contralateral lateral flexion ipsilateral lateral flexion Kolmogorov-Smirnov myofascial trigger point phonophoresis of hydrocortisone pain pressure threshold pressure release ultrasonic therapy visual analog scale

2 THREE METHODS FOR TREATING TRIGGER POINT, Sarrafzadeh 73 Table 1: Characteristics of Subjects Variable Control (n 15) UT (n 15) PR (n 15) PhH (n 15) P Age (y) Weight (kg) Height (cm) NOTE. N 60. Values expressed as mean SD unless noted otherwise. Results of ANOVA test showed no significant differences among the 4 groups. All subjects were given a clear explanation of tests and treatments approved by the Tehran University of Medical Sciences and signed the informed consent before taking part in this research. Patients were evaluated for the presence of a latent MTP in the upper trapezius muscle with manual palpation. Table 2 lists patients inclusion and exclusion criteria. 23,26 After the first evaluation session, patients were systematically assigned to 4 groups: PhH, PR, UT, and control (n 15 in each group). To find the MTP region in each session, a designed cm transparency sheet containing 1 and 4 lateral hollow parts was used after identification of the MTP. The sheet was placed on the point of MTP, and its 4 lateral parts were filled with skin markers in the first evaluation session. This made it easier to differentiate the MTP area throughout various sessions. Pain intensity, PPT, and active range of motion were evaluated by an experienced physiotherapist in all 6 sessions for all groups. Treatment groups were treated by using the mentioned techniques (PhH, PR, UT) from sessions 2 to 5, whereas in sessions 1 and 6, only assessment of primary outcomes (pain intensity, PPT, active range of lateral flexion) was carried out. The range of active ipsilateral flexion (ILF) and contralateral lateral flexion (CLF) of the cervical spine was measured by using a dual inclinometer a consisting of master and slave parts that records the greatest range of motion for each movement. The master part was placed parallel to the shoulders horizontally, and the slave part was placed on the lateral border of the head (fig 1). The reliability of this method was investigated in 30 healthy subjects before the study and an interclass correlation coefficient model 2, 1 of 97% and standard error of measurement of 0.99 were obtained. PPT was measured with a digital algometer a consisting of a 1-cm wide disk that was pressed vertically on the MTP. To provoke the patient s pain, pressure was increased with a speed of 1kg cm 2 s 1. 7,23 This procedure was performed 3 times with 10-second intervals, and the average value was determined as PPT. 6,23,27-29 Furthermore, to evaluate pain intensity, a pressure of 25N was exerted on the MTP using the algometer and patients were asked to show their pain on the visual analog scale (VAS). The VAS was a 10-cm horizontal line divided into 10 equal parts. After introducing candidates to the VAS, the evaluation took place and pain intensity was recorded. 23 To evaluate the magnitude of pain, the VAS was used simultaneously with the algometer, but for determining PPT, the algometer was used alone. 7,23 All patients were asked to lie down in a prone position, and the neck was placed in a neutral position during the study. Phonophoresis of Hydrocortisone PhH 1% (pulse mode, 1.2W/cm 2 ; 1MHz; spatial average temporal average, 0.2W/cm 2 for 5min) was applied by using a Sonopuls 434, b which had an applicator with a cross-sectional area of 1cm 2. Before the start of treatment, the therapist thoroughly cleaned the subject s skin with alcohol, and after specifying the concerned point, hydrocortisone 1% gel was applied over the MTP. During this treatment, the ultrasound applicator was moved rotationally on the MTP with similar speed and pressure for all subjects. 6,20,30-33 Pressure Release In this group, after identifying the MTP, the algometer disk was put on the MTP and pressure equal to the average PPT, which was obtained at the first evaluation session, was exerted. During this treatment, pressure increased after reported pain reduction by the patient until pain recurrence was reported. This procedure lasted about 90 seconds. 7,22-24,32 Ultrasonic Therapy This procedure was exactly like PhH, but without the use of hydrocortisone gel. The pulse mode 1.2W/cm 2 dose with 1MHz frequency for 5 minutes was applied. 20,30,33 This group was designed to indicate the effect of UT alone. Table 2: Inclusion and Exclusion Criteria Inclusion Criteria Presence of a palpable taut band in a skeletal muscle Presence of a nodule Presence of at least 1 hypersensitive tender spot in the taut band in response to 25N of pressure Exclusion Criteria Diagnosis of fibromyalgia syndrome according to the American College of Rheumatology History of whiplash injury History of cervical spine surgery Diagnosis of cervical radiculopathy or myelopathy determined by the primary care physician Having myofascial therapy within the past month before the study Presence of spontaneous referred pain pattern (Active Trigger Point) Presence of jump sign Being in the period of menstrual cycle Presence of postural disorders

3 74 THREE METHODS FOR TREATING TRIGGER POINT, Sarrafzadeh Control The control group was only evaluated during the 6 sessions they took part in for this study, and pain intensity, PPT, and range of lateral flexion at both sides were measured and recorded. This group was designed to assess the effects of the algometery method. Statistical Analysis A Kolmogorov-Smirnov (K-S) test was performed to determine normal distribution of each variable. Analysis of variance (ANOVA) test was used to determine whether there was a difference among the 4 groups regarding age, weight, and height. The data obtained were coded before analysis and the analysis process therefore was blinded. A mixed between-/withinsubjects ANOVA was conducted to assess the effects of sessions (6 levels) on dependent parameters. Bonferroni test was used for post hoc comparison. The confidence level was set at.05 for statistical significance. All statistical analyses were performed using SPSS statistical software, version c RESULTS The K-S test was not significant for all parameters. There was no significant difference in age, weight, and height among the 4 groups participating in this study (see table 1). Meanwhile, results of repeated-measures ANOVA indicated a significant decrease in pain intensity in all groups (P.001) except the control group, which showed a significant increase Fig 2. Mean values for pain in 6 sessions for 3 treatments and a control group. Repeated ANOVA indicated significant differences between the 3 treatment groups and the control group (P<.001). in pain intensity after 6 sessions (P.001). Results of Bonferroni post hoc test showed that effects of PhH and PR on pain reduction were significantly greater than UT (P.001) (fig 2). PPT increased significantly in all groups (P.001) except the control group, which showed a significant decrease (P.001). Bonferroni post hoc test showed that effects of PhH and PR on PPT were significantly greater than that of UT (P.001) (fig 3). There was a significant increase in CLF within sessions for all treatment groups (P.001) except the control group, which showed a significant decrease in CLF (P.02) (fig 4). There also was a significant increase in ILF within sessions for all treatment groups (P.001) (fig 5). Table 3 lists results of repeated-measures ANOVA test. DISCUSSION Various hypotheses were proposed to explain the cause of MTP. Consequently, an assortment of therapeutic methods (eg, PR, ultrasonography, injection) have been put forth as suggestions. 8,11,34,35 Generally, to treat MTPs, special attention should be given to 2 factors. The first is increasing blood supply to the MTP, whereas the second revolves around increasing the length of sarcomeres. 9 Simons 9 suggested that PR may cause pain reduction and might remove the involved MTPs by modifying the length of sarcomeres. Some studies indicated that blood supply may be limited in the neighborhood of the palpable MTP. 36,37 It seems that PR could be effective when ischemia and hypoxia are Fig 1. Measurement of active cervical range of motion using a dual inclinometer. Fig 3. Mean PPT values in 6 sessions for 3 treatments and a control group. Repeated ANOVA indicated significant differences between the 3 treatment groups and the control group (P<.001).

4 THREE METHODS FOR TREATING TRIGGER POINT, Sarrafzadeh 75 Fig 4. Mean ILF values in 6 sessions for 3 treatments and a control group. removed from the area. After pressing the MTP, ischemia may be created, and when that pressure was released, a sudden increment in local blood flow was inevitable. Consequently, increasing local blood flow may clean out pain-producing substances from the area, and stimulation of pain receptors may be reduced accordingly. Finally, by returning the condition of the area to normal, sarcomeres might be relieved from the short position and pain, and poor blood flow may be decreased or eliminated. 9,34 Releasing anesthesia (antipain) hormones such as endorphin and enkephalin after removing pressure from the MTP site, 38,39 neurologic inhibition, 40 and gate control theory 41 might be other mechanisms proposed for pain reduction and removal of relative symptoms after using PR. It seems that hand pressure applied by the therapist or the applicator pressure of the algometer in the present study on the latent MTP might release endorphins and enkephalins and cause neurologic inhibition and A mechanoreceptor activation and, as a consequence, may block the pain and remove motional limitation. 42,43 The influence of PR on trapezius latent MTPs in this study was consistent with findings of some previous studies. 7,20,23 However, they did not use an algometer in their treatment methods. In the present study, we used this evaluation device for better monitoring during PR treatment. Some studies used UT for treatment of MTPs. 19,20,30,33 Aguilera et al 20 indicated that UT decreased pain, but did not significantly increase active range of motion, in contrast to the present study. The difference may be due to the different methods of range-of-motion assessment. The mentioned study combined ILF and CLF values, whereas the present study evaluated these 2 factors separately. We used pulsed ultrasound, and because minimal or no thermal effect is produced with pulsed ultrasound, we could not relate treatment effects of the present study to thermal effects of UT. Meanwhile, some positive treatment effects in the UT and PhH groups could be due to the nonthermal effects of pulsed ultrasound energy, such as microstreaming. It seems that microstreaming can exert stress on the cell membrane and also clean out ions and molecules accumulated outside the cell due to cellular activity and membrane transport. In addition, rapidly changing pressure on cells and tissue structures, which has been called micromassage, can cause differential pressure between cell layers and tissue boundaries, which in turn would produce mechanical effects, such as change in permeability of cell membranes, and ultimately may lead to repairing a tissue. 44 While using ultrasound, the gate control mechanism could be mentioned again due to excitation of A mechanoreceptors. In this condition, messages produced from mechanoreceptors enter the spinal cord and quick pain impulses at the spinal cord become inhibited and pain would be blocked. 45 In the present study, UT was significantly effective in relation to the control group, similar to results of Srbely et al. 33 They investigated the effect of UT on MTPs of the supraspinatus and infraspinatus muscles, and the pain threshold rate at different times (1, 3, 5, 10, 15min) was studied. They reported that low-dose ultrasound evoked short-term antinociceptive effects on MTPs. The present study showed that both UT and hydrocortisone were effective for treatment of latent MTPs. As mentioned, tissue repair created by the mechanical effects of UT might be the reason behind some of the positive effects on latent MTPs in the present study for both the UT and PhH groups. However, there was a significant difference between the PhH and UT groups, and treatment was more successful in the PhH group. Although effects of phonophoresis could be attributed to the effects of UT and the drug, the significant difference between these 2 groups (UT and PhH) might be due to the use of hydrocortisone 1%. Hydrocortisone is an effective and potent anti-inflammatory steroid (corticosteroid) agent. However, in systematic (oral) use, it might be associated with a number of serious side effects. 45 Localized absorption and dispersion of hydrocortisone in the target tissue is an advantage of phonophoresis, and no side effects would be expected. 46 Shah et al 47 reported that levels of chemical mediators associated with pain and inflammation were elevated at points near and remote from active MTPs of the upper trapezius. In addition, they found no significant difference in inflammatory chemical mediator levels between patients with latent MTPs and healthy subjects. Our study showed that the effect of PhH on latent MTPs was significantly higher than that of UT. This may show that there might be some inflammatory changes in latent MTPs. Further studies should be carried out to clarify this issue. PhH was not used in previous studies for MTP. Recently, Ay et al 19 reported the effect of diclofenac phonophoresis on active MTPs. They compared phonophoresis with UT and sham UT. Their results showed a significant improvement in all factors, but no significant differences were found between phonophoresis of diclofenac and UT. 19 Diclofenac is a nonsteroidal anti-inflammatory drug associated with fewer serious side effects. It also is not as powerful in reducing inflammation as corticosteroids, 45 and this might be the cause of the nonsignificant difference between the ultrasonic and phonophoresis groups in the study by Ay et al. 19 Fig 5. Mean CLF values in 6 sessions for 3 treatments and a control group.

5 76 THREE METHODS FOR TREATING TRIGGER POINT, Sarrafzadeh Table 3: Results of Repeated-Measure ANOVA Test for 3 Treatments and a Control Group Main Effect (session) Variable Main Effect (group) Control (n 15) UT (n 15) PR (n 15) PhH (n 15) Interaction Effect Pain PPT ILF CLF NOTE. N 60. Some new studies suggested that sympathetic vasoconstriction activity may be increased at latent MTPs The question is whether therapeutic methods could affect sympathetic vasoconstriction activity of the MTP area. One of the advantages of the present study was investigating the pure effect of algometry. Our results indicated that this evaluation method had no confounding effect on the treatment of latent MTPs. Another innovation in our study was using a designed sheet that permitted us to determine the latent MTP in various follow-up sessions. Study Limitations Because cervical rotation was not evaluated and only women were recruited, performing new research in both sexes and considering cervical rotation is proposed. Using PhH therapy in a large population and for active MTPs also is recommended. Investigating the short-term effects of treatment methods is 1 of the other limitations of the present study. CONCLUSIONS According to the present study, PhH and PR were 2 suitable methods for latent MTPs. PhH was not used in previous studies for the treatment of latent MTPs and now is being introduced as an effective and suitable treatment for latent MTPs. Acknowledgments: This research was a part of an MSc thesis (Marziyeh Yassin, Tehran University of Medical Sciences, March 2010). References 1. Simons DG, Travell JG. Myofascial pain and dysfunction: the trigger point manual. Baltimore: Williams & Wilkins; Simons DG, Travell JG, Simons LS. Travell & Simons myofascial pain and dysfunction: upper half of body. 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