LITERATURE REVIEW. Authors: Affiliations: Correspondence: Disclosures: ABSTRACT. Neck Pain

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1 Authors: Barbara Cagnie, PT, PhD Birgit Castelein, PT, MSc Flore Pollie, PT, MSc Lieselotte Steelant, PT, MSc Hanne Verhoeyen, PT, MSc Ann Cools, PT, PhD Affiliations: From the Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium. Correspondence: All correspondence and requests for reprints should be addressed to: Barbara Cagnie, PT, PhD, Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185 3B3, 9000 Ghent, Belgium. Disclosures: Author Castelein is funded by BOF- UGent 01D Authors Cagnie and Castelein contributed equally to this article. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article /15/ American Journal of Physical Medicine & Rehabilitation Copyright * 2015 Wolters Kluwer Health, Inc. All rights reserved. DOI: /PHM LITERATURE REVIEW Neck Pain Evidence for the Use of Ischemic Compression and Dry Needling in the Management of Trigger Points of the Upper Trapezius in Patients with Neck Pain A Systematic Review ABSTRACT Cagnie B, Castelein B, Pollie F, Steelant L, Verhoeyen H, Cools A: Evidence for the use of ischemic compression and dry needling in the management of trigger points of the upper trapezius in patients with neck pain. Am J Phys Med Rehabil 2015;00:00Y00. The aim of this review was to describe the effects of ischemic compression and dry needling on trigger points in the upper trapezius muscle in patients with neck pain and compare these two interventions with other therapeutic interventions aiming to inactivate trigger points. Both PubMed and Web of Science were searched for randomized controlled trials using different key word combinations related to myofascial neck pain and therapeutic interventions. Four main outcome parameters were evaluated on short and medium term: pain, range of motion, functionality, and quality-of-life, including depression. Fifteen randomized controlled trials were included in this systematic review. There is moderate evidence for ischemic compression and strong evidence for dry needling to have a positive effect on pain intensity. This pain decrease is greater compared with active range of motion exercises (ischemic compression) and no or placebo intervention (ischemic compression and dry needling) but similar to other therapeutic approaches. There is moderate evidence that both ischemic compression and dry needling increase side-bending range of motion, with similar effects compared with lidocaine injection. There is weak evidence regarding its effects on functionality and quality-of-life. On the basis of this systematic review, ischemic compression and dry needling can both be recommended in the treatment of neck pain patients with trigger points in the upper trapezius muscle. Additional research with high-quality study designs are needed to develop more conclusive evidence. Key Words: Trigger Points, Ischemic Compression, Dry Needling, Upper Trapezius Ischemic Compression and Dry Needling in Neck Pain 1

2 Neck pain is a growing 21st century health concern, affecting 45%Y54% of the general population. 1 Activities that require repetitive use of the same muscle (group) or prolonged poor postures (e.g., office workers) can lead to the development of myofascial pain syndrome. 2 The latter is characterized by the presence of one or more trigger points (TPs), often in the upper trapezius (UT), which can be defined as a hyperirritable spot within a taut band of a skeletal muscle. 3 Patients with TPs are generally characterized by the presence of one or more of the following symptoms: local pain, referred pain according to a typical pattern, pain when exerting compression or stretch on the muscle, local twitch response (LTR) provoked by the snapping palpation of the taut band, reduced force, and decreased range of motion (ROM). 3 A combination of these symptoms can result in less functionality and quality-of-life. As a consequence, pain, ROM, and functionality are frequently used to measure the effect of treatment in patients with myofascial pain syndrome. A variety of therapeutic techniques exist to inactivate the TPs, with the most commonly used techniques being ischemic compression (IC) and dry needling (DN). 4,5 Ischemic compression is a manual technique in which the physiotherapist applies pressure directly on the TP. Different parameters are used to define the amount of pressure, such as pain or tissue resistance. Dry needling is another commonly used technique that has gained popularity over the last few years, in clinical practice as well as for research purposes. 6,7 It involves the insertion of a fine, solid filiform needle without introduction of any analgesic medication. Several DN techniques in the context of TPs are noted in the literature. 8,9 Two subtypes, that is, superficial and deep DN, exist. Within the superficial technique, the needle is inserted 5-mm deep, aiming an indirect effect on pain by inhibiting C-fiber pain impulses. Using deep DN, there is a direct stimulation of the affected muscle eliciting an LTR, with different physiological effects. 7 Inserting the needle deeper affects skin, fascia, and muscle and has abetteranalgesiceffect than when inserted only into the skin and superficial muscle. 8,10,11 The needle can be moved up and down like a piston, but it can also be left in situ for awhile. 8 There is some evidence suggesting that IC is effective at short term for reducing TP-related symptoms in individuals with mechanical neck pain. 12 Arecentmeta-analysisbyKietrysetal. 13 reported that DN is beneficial for decreasing pain immediately after treatment and at a 4-wk follow-up in patients with neck pain. There is, however, no recent systematic literature overview investigating the effects of both IC and DN in patients with neck pain. The aim of this review was to determine the evidence base for the effect of both treatments and compare them with other (non-)physiotherapeutic approaches aiming to inactivate TPs. METHODS Information Sources and Search Strategy The search strategy has been executed in December 2013 in the electronic databases PubMed ( and Web of Science ( using the CO (Participant, Intervention, Comparison, Outcome) approach. 14 Studies assessing the effects of IC and/or DN (I) compared with other (non-) physiotherapeutic treatments (C) on pain, ROM, functionality, and quality-of-life (O) in patients with TPs in the neck (P) were considered in this systematic review. The search strategy was based on a combination of the following MeSH terms or free-text words: (BNeck Pain[[Mesh] OR Bneck[) AND (BTrigger Points[[Mesh] OR Btrigger point[ OR BTrigger Area[ OR Bischemic compression[ OR Bdry needling[ OR Bmyofascial release[ OR Bpressure release[). B[MESH][ was left out in the Web of Science search. Furthermore, reference lists of review articles were scanned. To be included, the study had to meet the following inclusion criteria: (1) Only RCTs were included in this analysis; (2) Participants with neck pain must be diagnosed with active or latent TPs in the UT; (3) DN and/or IC must be used as intervention (DN was defined as an Bintramuscular procedure,[ i.e., the insertion of needles into TPs 15 ); (4) Only articles concerning the therapeutic effects of treatment were included. Articles about side effects or complications were excluded. Only articles meeting all 4 criteria were included. Articles describing the effects of acupuncture treatment, but meeting all the other inclusion criteria, were read by the reviewers. When during the acupuncture treatment the skin was pierced until the TP was reached (as with DN), the study was included. In the first phase, the selection criteria were only applied to the title and abstract. For all possible eligible studies, full texts were retrieved. In the second phase, selection was based on the full-text articles, screened by two independent reviewers. 2 Cagnie et al. Am. J. Phys. Med. Rehabil. & Vol. 00, No. 00, Month 2015

3 Qualification of Methodological Quality The checklist for RCTs, developed by the Dutch Cochrane Centre and Dutch Institute for Healthcare Improvement, was used to assess the methodological quality. Three independent, blinded researchers scored all the included articles. The possible answers were Byes[ (one point) and Bno[ as well as Binsignificant information[ or Bnot answered[ (zero points). Scores were compared, and disagreements were discussed until a consensus was reached. As a measure of interobserver agreement, the intraclass correlation coefficient was calculated. In this review, only studies scoring at least 50% on the quality assessment were included. In this review, a quality score of 5/9 or 6/9 was considered as moderate quality, whereas studies scoring 7/9 or 8/9 were considered as good quality. Depending on methodological quality, a level of evidence was determined according to the 2005 classification system of the Dutch Institute for Healthcare Improvement ( An BA2[ classification is given to RCTs of good quality and of sufficient size and consistency. Randomized controlled trials of moderate quality or insufficient size are classified as BB.[ Finally, a strength of conclusion was calculated for each outcome parameter and was placed between brackets when describing the results. A strength of conclusion 1 is given when there are at least two independently conducted studies of A2. A strength of conclusion 2 is given when there are at least two independently conducted studies of level B or one study of level A2; a strength of conclusion 3, when there is one study of level B. To structurally present the relevant data from the articles, an evidence table was created (Table 1). The following items were systematically extracted from every article: author, patient groups, intervention, control and/or comparison intervention, outcome parameters, as well as main results. The data were extracted independently by two reviewers (F. Pollie and L. Steelant) and were compared and merged afterward. RESULTS Study Selection The search for studies resulted in a total of 369 references and 8 Bhand-searched[ articles. After de-duplication and the 2 screening phases based on the selection criteria, 21 relevant RCTs remained. After a methodological assessment, 6 of the 21 articles scored less than 50% (G5/9) and were excluded, leading to a total of 15 studies qualified for inclusion. An overview of the study selection is presented in Figure 1. Assessment of Methodological Quality Table 2 shows the quality of each article. Interobserver agreement resulted in an intraclass correlation coefficient of 0.77 (initial disagreement in 31 of the 135 items). An important limitation of the methodological quality of many studies was the lack of blinding of the practitioner and/or patients. Six articles were of low quality and were not further included in the analysis; 9, of moderate quality; and 6, of good quality. Eighty percent of the articles are scored as level B studies, whereas 20% of the articles are classified as level A2. Study Characteristics As presented in Table 1, the number of patients varied between 39 and 117 in each study. 22,25 Of all included articles, there were 7 that described the effects of IC. 16Y22 In the other 8 studies, the effect of DN was investigated. 23Y30 No articles compared IC with DN. In all studies, only short- or medium-term effects were evaluated, with a maximum follow-up period of 3 mos. Synthesis of Results Pain All articles used pain as an outcome measurement, including pain intensity (measured with the visual analog scale), pressure pain threshold (PPT), and pressure pain intensity (). When measuring PPT or, the pressure was applied with an algometer. Pressure pain threshold measures the point where the applied pressure starts to change into a pain sensation, whereas is the intensity of pain that the patient senses when a certain amount of pressure is applied (mostly 2.5 kg/cm 2 ). Pressure pain intensity is evaluated using the tenderness grading scale or the visual analog scale. In all IC studies evaluating pain intensity, the score on the visual analog scale was reduced (strength of conclusion 2). 18Y21 There was a greater decrease after IC compared with active ROM exercises. 19 Although Gemmell et al. 18 did not find a statistically significant difference between IC and ultrasound (US), a clinically significant difference was shown with an odds ratio IC/US of Nagrale et al. 21 demonstrated the added value of therapeutic combinations. A treatment consisting of only muscle energy techniques (MET) showed less improvement than the combination with IC and Ischemic Compression and Dry Needling in Neck Pain 3

4 4 Cagnie et al. Am. J. Phys. Med. Rehabil. & Vol. 00, No. 00, Month 2015 TABLE 1 Evidence table Ischemic compression Aguilera et al. 16 Fernandezde-las-Penas et al. 17 Gemmell et al. 18 Hanten et al. 19 Patients Intervention Control Outcome Main Results Subjects with ltps in UT n = 66; 29SY379 inp (atps in UT) n = 40; 17SY239 inp (atps in UT) n = 45 Subjects with TPs in the neck/upper back IC (n = 22) Duration: 90 secs Frequency: 1 session US (n = 22): 2 mins on both trapezius muscles alternatively Baseline and after treatment: :, in IC and US, but not in sham US ROM: j in side bending Sham US (n = 22): 5 mins, in IC only apparatus not connected. ROM: side bending IC (n = 20) Transverse friction massage Baseline and 2 mins PPT: j in both groups, but no (n = 20): 3 mins after treatment difference between the groups Duration: 90 secs PPT :, in both groups, but no difference between the groups Frequency: 1 session IC (n = 15) PR (n = 15): Baseline and 5 mins :, in IC, PR, sham US, but no after treatment difference between the groups. Duration: 30 secsy1 mins Duration: until release PPT: j in all groups, but no or up to 90 secs differences between the groups Frequency: 1 session Frequency: 1 session PPT ROM: j in side bending in all groups, but no difference between the groups Sham US (n = 15): 2 mins ROM: side bending IC (+ stretching) Active ROM exercises (n = 20): Baseline and 3 days : greater, in IC (n = 20): 2timesadayfor5days after treatment n = 40; 17SY239 Duration: until release (24 hrs) PPT: greater j in IC Frequency: 10 sessions PPT (2 times a day for 5 days) Remark: use of theracane (self-treatment) Kannan et al. 20 inp (atps in UT) IC (+ UT stretch at home) (n = 15): n = 45; 23SY229 Duration: until release or up to 90 secs (repetition if no release) US over the most tender spot (n = 15): 5 mins (+ UT stretch at home) Laser (30 secs) (+ UT stretch at home) Baseline and immediately after treatment :, in all groups ROM: j in side bending in all groups (n = 15) Frequency: 5 sessions ROM: side bending Laser therapy had a tendency toward a better improvement than the other two groups did Nagrale et al. 21 inp (atps in UT) IC (n = 30): INIT (n = 30) Baseline, 2 and 4 wks after initiation of therapy n = 60; 25SY359 Duration: until release or up to 90 secs Frequency: 12 sessions (3 times a week for 4 wks) ROM: side bending NDI Improvement in both groups for all parameters jimprovement for INIT at 2 and 4 wks (Continued on next page)

5 Ischemic Compression and Dry Needling in Neck Pain 5 TABLE 1 (Continued) Patients Intervention Control Outcome Main Results Oliveira-Campelo et al. 22 Unilateral inp (atps in UT) IC (n = 24): S (n = 23): 30 secs Baseline, immediately, 24 hrs and 1-wk after treatment PPT: j in IC, MET, and S and, in P and WS, immediately after treatment n = 117; 32SY859 Duration: 90 secs MET (n = 23) PPT j in IC and, in MET and S, 24 hrs and 1 wk after treatment Frequency: 1 session P (n = 25) :, in IC and MET until one wk after treatment;, in S and P only was immediately after treatment Dry needling Ay et al. 23 Eroglu et al. 24 inp (atp in UT) n = 80; 28SY529 inp (atp in UT) n = 60; 7SY539 Ga et al. 25 inp (atp in UT) n = 43; 5SY389 Ga et al. 26 inp (atp in UT) n = 40; 4SY369 DN (+neck exercises for 12 wks) (n = 40) Duration: forward and backward needling, until there were no more LTRs Frequency: 1 session DN (+ self-stretching) (n = 20) Duration: 20 repetitions of rapid movements until the LTR was no longer perceived. Frequency: 3 sessions (1st, 3rd, and 14th day). DN (+ self-stretching 3 times a day) (n = 22): Duration: forward and backward needling, until there were no more LTR Frequency: 3 sessions (1st, 7th, and 14th day) WS (n = 22) Lidocaine injection (+ neck exercises for 12 wks) (n = 40) Lidocaine injection (+ self-stretching) (n = 20) Lidocaine injection + (self-stretching 3 times a day) (n = 21) DN without paraspinal needling DN with paraspinal (+ self-stretching 3 times a day) needling (multifidus (n = 18) C3YC5) (+ self-stretching 3timesaday)(n=22) ROM: flexion, extension, side bending, and rotation Baseline, 4 wks and 12 wks after DN treatment: No difference between the groups ROM: flexion, extension, side bending, rotation Depression: Beck depression inventory Baseline, on the 3rd and 14th day of treatment PPT ROM: flexion, extension, side bending, rotation Quality-of-life: Nottingham Health Profile Measurements on days 0, 7, 14, and 28 just before each treatment : shoulder, neck, and headache ROM: flexion, extension, side bending, rotation Depression: Geriatric Depression Scale (Short Form) Measurements on days 0, 7, 14, and 28 just before each treatment ROM: j in contralateral side-bending and ipsilateral rotation, immediately after treatment in IC, MET, and S, but 24 hrs and 1 wk after treatment in IC only Improvement in both groups for all parameters after 4 and 12 wks Improvement in all groups on the 3rd and 14th day of treatment No difference between the groups NSAID (+self stretching) (n = 20) and :, in both groups (no difference between the groups) ROM: j in both groups, except for extension in the TP needling group Depression: a trend toward, in both groups and :, in both groups, (no difference between groups) (Continued on next page)

6 6 Cagnie et al. Am. J. Phys. Med. Rehabil. & Vol. 00, No. 00, Month 2015 TABLE 1 (Continued) Patients Intervention Control Outcome Main Results Duration: forward and backward needling, until there were no more LTRs Depression:, in DN with paraspinal needling only Frequency: 3 sessions (1st, 7th, and 14th day) Hong et al. 27 inp (atp in UT) DN (+ stretching) (n = 23) n = 58; 16SY429 Duration: forward and backward needling, until there were no more LTRs Lidocaine injection (+ stretching) (n = 35) : shoulder, neck, and headache ROM: flexion, extension, side bending, rotation Depression: Geriatric Depression Scale (Short Form) Baseline, immediately, and 2 wks after treatment PPT Frequency: 1 session ROM: side bending Itoh et al. 28 cnp DN (n = 10) Non-TP DN (n = 10) : baseline +1, 2, 3, 6, 7, 8, 9, and 12 wks after the first treatment. n = 40; 11SY299 Duration: until LTR was elicited, the needle was left in place for 10 mins. Frequency: 6 sessions over 10 wks Ma et al. 29 cnp (atps in UT) DN (+ self-stretching) (n = 15) n = 43; 21SY229 Duration: forward and backward needling, until there were no more LTRs Frequency: 2Y4 sessions over 2 wks Sham acupuncture (n = 10) Standard acupuncture (n = 10) Self-stretching (n = 13) MSN (+ self-stretching) (n = 15) Myburgh et al. 30 Asymptomatic: n = 40 DN (n = 37) Superficial DN (n = 40): depth of inp (atps in UT): Duration: depth of 10 mm 5 mm for 90 secs n = 37 for 90 secs until LTR (no LTR was expected) was no longer elicited Frequency: 1 session NDI: baseline +3, 6, 9, and 12 wks after the first treatment Baseline, 2 wks and 3 mos after treatment PPT ROM: side bending Baseline, immediately and 48 hrs after treatment: PPT ROM: j in both groups, except for extension in DN-only group Depression:, in DN with paraspinal needling only :, in both groups immediately after treatment, but no difference between the groups. Greater, in lidocaine injection group 2 wks after treatment PPT, ROM: j immediately after treatment in both groups, effects decreased 2 wks after treatment (no difference between the groups) :, in all groups, but with different time course. After 9 wks, the DN group reported relatively lower than the other groups did. NDI:, in the DN group only Greater improvement for MSN and DN for all parameters compared with self-stretching at 2-wks and 3-mos follow-up Greater,, j PPT and jrom in MSN compared with DN at 3 months follow-up :, in both groups, but no difference between the groups PPT:, in both groups, but no difference between the groups atp, active trigger point; cnp, chronic neck pain; INIT, integrated neuromuscular inhibition technique: combination of MET, IC, and strain-counterstrain; inp, idiopathic neck pain; ltp, latent trigger point; NSAID, nonsteroidal anti-inflammatory drug; P, placebo stretching,, pain intensity; PR, pressure release; S, passive stretching; WS, wait-and-see; decrease; increase; S male; 9 female.

7 FIGURE 1 Flow chart study selection. strain-counterstrain did, which is also called integrated neuromuscular inhibition technique. The pain intensity after DN decreased in all DN studies (strength of conclusion 1). 23Y30 However, only Itoh et al. 28 demonstrated greater improvement of the DN intervention compared with other forms of treatment. They demonstrated a longlasting effect of 6 sessions of DN compared with non-tp DN, sham, and standard acupuncture. Two other studies 27,29 demonstrated other treatments to be more effective. Ma et al. 29 found a significant decrease in pain intensity for miniscalpel needling (MSN) and DN, but MSN had a more prolonged effect than DN. Hong et al. 27 demonstrated a similar improvement in pain intensity immediately after both DN and lidocaine injection. However, two wks after treatment, the reduction in pain intensity was significantly greater after lidocaine injection. In all IC studies evaluating PPT, the threshold increased after IC (strength of conclusion 2). 17Y19,22 The increase after IC was greater compared with active ROM exercises 19 and no or placebo intervention. 22 In comparison with MET and passive stretching, IC seemed to have a longer-lasting effect on PPT. 22 There was a significant increase for the PPT after DN in all studies, 24,27,29 except for the study of Myburgh et al., 30 who demonstrated an increased tissue sensitivity for the entire cohort over time (strength of conclusion 2). Both Eroglu et al. 24 and Hong et al. 27 did not find a difference between DN and lidocaine injection on PPT. In all studies evaluating, there was a significant decrease in after IC (strength of conclusion 2). 16,17,22 This decrease in was significantly greater in IC compared with sham US, 16 but it was equal to transverse friction massage, 17 US, 16 passive stretching, 22 and MET 22 immediately after treatment. However, the study of Oliveira-Campelo et al. 22 showed a more prolonged effect for IC in comparison to passive stretching and placebo. Only Ga et al. 25,26 evaluated the effect of DN on in two different studies (strength of conclusion 2). They found a decrease in after DN, but this was not different from lidocaine injection 25 or DN with paraspinal needling. 26 Range of Motion Five of 7 studies evaluated ROM as an outcome measure of IC. 16,18,20Y22 All studies evaluated side bending, whereas only one study evaluated flexion, extension, and rotation as well Ischemic Compression and Dry Needling in Neck Pain 7

8 TABLE 2 Risk for bias and level of evidence for randomized controlled trials RCT Score Level of Evidence Ischemic compression Aguilera et al j j +? +? + 5/9 B Fernandez-de-las-Penas et al j j + +?? + 5/9 B Gemmell et al j j /9 B Hanten et al j j +?? + + 5/9 B Kannan et al. 20 +? j j /9 B Nagrale et al j j? j /9 B Oliveira-Campelo et al j j + j /9 B Dry needling Ay et al j? /9 B Eroglu et al j j j + +? + 5/9 B Ga et al j j /9 B Ga et al. 26 +? + j j /9 B Hong et al. 27 +? + j /9 A2 Itoh et al j j + 7/9 A2 Ma et al j j? /9 B Myburgh et al j /9 A2 Items: 1, randomization; 2, blinding of the randomization procedure; 3, blinding of patients; 4, blinding of practitioner; 5, blinding of outcome assessor; 6, comparability of groups; 7, lack of loss to follow-up; 8, intention-to-treat analysis; 9, comparability of treatment.?, not enough information; +, yes; j, no. Ischemic compression had a positive effect on the ipsilateral and contralateral side bending (strength of conclusion 2). The combination of IC, MET, and strain-counterstrain resulted in greater improvement than MET only. 21 The increase in side-bending ROM after IC was equal to MET and passive stretching immediately after treatment, but it was significantly greater 24 hrs and 1 wk after treatment. 22 Aguilera et al. 16 demonstrated greater improvement in side bending after IC compared with US and sham US, but this was in contrast to the study of Gemmell and Allen 18 (sham US) as well as that of Kannan 20 (US), who did not find a difference in improvement. The effect of DN on ROM was described in 6 studies. 23Y27,29 All studies evaluated all directions of movement in the cervical spine, except for the studies of Ma et al. 29 and Chen et al., 31 who only evaluated side bending. Most studies compared the effects of DN with lidocaine injection and found a similar improvement in both groups after intervention for all range of movements (strength of conclusion 2). Only for extension, there were some conflicting results: Hong et al. 27 demonstrated in two studies that lidocaine injection and DN with paraspinal needling resulted in a greater improvement in extension ROM compared with DN only, whereas Ay et al. 23 and Eroglu et al. 24 did not find a difference between groups. Functionality Only 2 studies assessed the degree of functionality using the Neck Disability Index (NDI). 21,28 There was a reduction in the NDI score, both after treatment with IC 21 and DN 28 (strength of conclusion 3). Nagrale et al. 21 found a larger improvement in disability for the combination of IC, MET, and strain-counterstrain, compared with MET alone. Dry needling resulted in a significant decrease in the NDI score, whereas there was no significant decrease in the non-tp, placebo, and standard acupuncture groups. 28 Quality-of-Life and Depression Four studies evaluated the effect of DN on quality-of-life 24 and depression. 23,25,26 Eroglu et al. 24 used the Nottingham Health Profile to evaluate the quality-of-life after DN intervention and found a significant improvement that was equal to lidocaine injection and the use of nonsteroidal antiinflammatory drug (strength of conclusion 3). Regarding the assessment of depression, only Ay et al., 23 using the Beck Depression Inventory, found a significant improvement after treatment with DN (strength of conclusion 3), whereas Ga et al., 26 using the Geriatric Depression Scale (Short Form), only found a reduction in the group that received DN in combination with paraspinal needling. 8 Cagnie et al. Am. J. Phys. Med. Rehabil. & Vol. 00, No. 00, Month 2015

9 DISCUSSION The goal of this systematic review was to summarize the existing knowledge about the efficacy of IC and DN on patients with myofascial TPs in the UT. Pain, ROM, functionality, and quality-of-life were used as outcome parameters to describe the effects of those two treatments. Before discussing the results, it is important to highlight some methodological limitations of the current systematic review. It was opted to only focus on the most common parameters, that is, pain, ROM, functionality, and quality-of-life, but the description of other outcome parameters such as strength and muscle electrical activity may be relevant, too. Secondly, for both interventions (IC and DN), no MeSH terms could be found, which required the use of synonyms in the search strategy. As a consequence, this could have led to an incomplete retrieval of suitable articles. Finally, in some studies, combined interventions might have influenced the results regarding the relative contribution of IC or DN to treatment effects often making the conclusions doubtful. For example, in different studies, 19,20,24Y27,29 subjects in all groups performed stretching exercises. In these studies, it is possible that the stretching exercises contributed to the treatment effects. All studies using IC as intervention showed a reduction in pain and improvement of ROM after treatment. There is moderate evidence that the reduction in pain and improvement of ROM after IC is greater compared with active ROM exercises as well as no or placebo intervention but equal to transverse friction massage, US, passive stretching, and MET immediately after treatment. In comparison with MET and passive stretching, IC seems to have an effect on PPT that lasts for a longer period of time. There are some dissimilarities between the IC studies that should be taken into account when making conclusions. Comparison between studies is complicated because of the variance in treatment modalities, for example, duration and amount of pressure as well as treatment frequency. The variation in duration was limited because most studies applied pressure until release occurred or up to 90 seconds, with or without repetition of the technique. There was, however, more variety between the different studies in the amount of pressure that was used. Two studies 16,22 increased pressure until the patient reported a pain value of 7 of 10 on the visual analog scale, whereas two other studies 18,21 used tissue resistance to determine the amount of pressure. Other indicators were PPT 17 and tolerably painful, sustained pressure (ranging from 20 to 30 lbs). 20 Finally, there was also a divergence in treatment frequency ranging from 1 session to 12 sessions over 4 wks. It is currently unknown what the optimal treatment modalities are. There is strong evidence that DN has an analgesic effect, whereas the evidence is moderate to weak with respect to its effect on ROM and disability. Only one study 28 showed a longer-lasting effect of DN compared with sham or control. In the same study, 28 DN on tender points was favored over DN of nontender points or acupuncture. On the basis of 4 studies, 23Y25,27 DN seemed to be not superior to lidocaine injection. Interestingly, Hong 27 emphasized that it is essential for the efficacy of DN to elicit LTRs, which supports the theory that an LTR is an important component of effective DN. Recent animal and human studies have concluded that induction of an LTR is the important factor to make the best analgesic effectiveness. 32Y34 In the description of the DN technique included in this systematic review, it was not always clear whether an LTR was desired or elicited upon DN. In further clinical studies, it is recommended to indicate the presence of an LTR to confirm whether this is a valid predictor of success. The dosage of DN used in the different RCTs (frequency of sessions, duration of needle insertion, number and thickness of needles) is variable. For example, the frequency of sessions ranged from 1 single session of DN to 6 sessions of DN over 10 wks, which makes the interpretation of the collective body of results complicated. The optimal dosage remains unclear and requires further research. Besides further clarification of the effect of an LTR and the determination of the optimal treatment modalities, some other aspects need further investigation to develop more conclusive evidence for IC and DN. More high-quality RCTs are needed to further elucidate the effects of DN and IC compared with appropriate comparative treatments both on the short and long term. Until now, most studies have evaluated the immediate effect of IC and DN, with only a few studies describing longerterm effects. Although the goal of DN and IC is often rapid relief of pain so that patients can be progressed to other forms of therapy, further research of long-term effects is needed. Finally, it is currently unknown whether the benefits of DN exceed that of IC because no literature focusing on the specific comparison of IC and DN exists. This could be a challenge for further research. CONCLUSIONS There is moderate evidence that IC results in pain reduction, whereas there is strong evidence Ischemic Compression and Dry Needling in Neck Pain 9

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