ArticlePDF AvailableLiterature Review

Abstract

Background: Myofascial trigger point (MTrP) injection and trigger point dry needling (TrPDN) are widely accepted therapies for myofascial pain syndrome (MPS). Empirical evidence suggests eliciting a local twitch response (LTR) during needling is essential. Objective: This is the first review exploring the available literature, regardless of study design, on the neurophysiological effects and clinical significance of the LTR as it relates to reductions in pain and disability secondary to MTrP needling. Methods: PubMed, MEDLINE, Science Direct and Google Scholar were searched up until October 2016 using terms related to trigger point needling and the LTR. Results: and Discussion: Several studies show that eliciting a LTR does not correlate with changes in pain and disability, and multiple systematic reviews have failed to conclude whether the LTR is relevant to the outcome of TrPDN. Post needling soreness is consistently reported in studies using repeated in and out needling to elicit LTRs and increases in proportion to the number of needle insertions. In contrast, needle winding without LTRs to MTrPs and connective tissue is well supported in the literature, as it is linked to anti-nociception and factors related to tissue repair and remodeling. Additionally, the positive biochemical changes in the MTrP after needling may simply be a wash out effect related to local vasodilation. While the LTR during TrPDN appears unnecessary for managing myofascial pain and unrelated to many of the positive effects of TrPDN, further investigation is required.
Accepted Manuscript
The local twitch response during trigger point dry needling: Is it necessary for
successful outcomes?
Thomas Perreault, DPT, James Dunning, DPT, MSc, FAAOMPT, Raymond Butts,
DPT, PhD, MSc
PII: S1360-8592(17)30031-1
DOI: 10.1016/j.jbmt.2017.03.008
Reference: YJBMT 1493
To appear in: Journal of Bodywork & Movement Therapies
Received Date: 12 December 2016
Revised Date: 17 February 2017
Accepted Date: 28 February 2017
Please cite this article as: Perreault, T., Dunning, J., Butts, R., The local twitch response during
trigger point dry needling: Is it necessary for successful outcomes?, Journal of Bodywork & Movement
Therapies (2017), doi: 10.1016/j.jbmt.2017.03.008.
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The Local Twitch Response During Trigger Point Dry Needling: Is it Necessary For Successful
Outcomes?
Authors:
Thomas Perreault, DPT, OCS, Faculty, American Academy Of Manipulative Therapy Fellowship in
Orthopedic Manual Physical Therapy. Senior Instructor, Spinal Manipulation Institute & Dry Needling
Institute, Montgomery, Alabama
James Dunning, DPT, MSc, FAAOMPT, Alumno de Doctorado, Escuela Internacional de Doctorado,
Universidad Rey Juan Carlos, Alcorcon, Madrid, Spain
Raymond Butts, DPT, PhD, MSc, Faculty, American Academy Of Manipulative Therapy Fellowship in
Orthopedic Manual Physical Therapy. Senior Instructor, Spinal Manipulation Institute & Dry Needling
Institute, Montgomery, Alabama
Corresponding Author:
Dr. Thomas Perreault
American Academy of Manipulative Therapy, 1036 Old Breckenridge, Ln., Montgomery, Alabama, USA
Postal Code: 36117
Tel: 603-781-2782
Email: tommy.perreault@gmail.com
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The Local Twitch Response During Trigger Point Dry Needling: Is it Necessary For
Successful Outcomes?
Abstract:
Background: Myofascial trigger point (MTrP) injection and trigger point dry needling (TrPDN)
are widely accepted therapies for myofascial pain syndrome (MPS). Empirical evidence suggests
eliciting a local twitch response (LTR) during needling is essential.
Objective: This is the first review exploring the available literature, regardless of study design,
on the neurophysiological effects and clinical significance of the LTR as it relates to reductions
in pain and disability secondary to MTrP needling.
Methods: PubMed, MEDLINE, Science Direct and Google Scholar were searched up until
October 2016 using terms related to trigger point needling and the LTR.
Results and Discussion: Several studies show that eliciting a LTR does not correlate with
changes in pain and disability, and multiple systematic reviews have failed to conclude whether
the LTR is relevant to the outcome of TrPDN. Post needling soreness is consistently reported in
studies using repeated in and out needling to elicit LTRs and increases in proportion to the
number of needle insertions. In contrast, needle winding without LTRs to MTrPs and connective
tissue is well supported in the literature, as it is linked to anti-nociception and factors related to
tissue repair and remodeling. Additionally, the positive biochemical changes in the MTrP after
needling may simply be a wash out effect related to local vasodilation. While the LTR during
TrPDN appears unnecessary for managing myofascial pain and unrelated to many of the positive
effects of TrPDN, further investigation is required
.
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The Local Twitch Response During Trigger Point Dry Needling: Is it Necessary For
Successful Outcomes?
Introduction
Myofascial pain syndrome (MPS) is a highly prevalent condition without clear evidence-based
clinical guidelines for optimal management (Fleckenstein et al., 2010). According to a recent
international survey, pain specialists consider MPS to be a readily distinguishable condition
involving local muscle pain and the presence of tender spots that reproduce symptoms when
pressure is applied (Rivers et al., 2015). Clinically, MPS is associated with the presence of
myofascial trigger points (MTrPs), which are often the focus of examination and treatment (Shah
et al., 2015). A MTrP is a palpable, hyperirritable nodule located within a taut band of skeletal
muscle fibers that is classified into an active (A-MTrP) or latent (L-MTrP) myofascial trigger
point (Ge et al., 2011). A-MTrPs are associated with pain recognition when manually stimulated,
and often present with predictable pain referral patterns (Myburgh et al., 2008); furthermore, A-
MTrPs have the potential to cause both peripheral and central sensitization (Fernandez-de-las-
Penas & Dommerholt, 2014; Hsieh et al., 2007). L-MTrPs are only painful with compression or
palpation (Bron et al., 2011), however, they may predispose patients to altered movement
patterns (Ge et al., 2012; Ge et al., 2014; Ibarra et al., 2011; Lucas et al., 2010; Sergienko &
Kalichman, 2015) and/or be converted to A-MTrPs when perpetuating factors are present (Ge &
Arendt-Nielsen, 2011). Importantly, MTrPs are prevalent in patients with musculoskeletal pain
(Alburquerque-García et al., 2015; Arendt-Nielsen, 2015; Bron et al., 2011; Castaldo et al., 2014;
Fernandez-Carnero et al., 2007; Fernández-de-las-Peñas et al., 2005; Sergienko & Kalichman,
2015) and a multitude of causes for MTrP development have been suggested (Campa-Moran et
al., 2015; Huang et al., 2014; Itoh et al., 2004; Lin et al., 2011; Ruiz-Saez et al., 2007; Treaster et
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al., 2006; Tsai et al., 2009). MTrP injection and trigger point dry needling (TrPDN) are
commonly applied interventions for MTrP pain (Kuan, 2009) . Several studies suggest the effects
of injection therapy are largely due to mechanical disruption of muscle fibers and nerve endings
from the prick of the needle, not solely from the infiltration of a local anesthetic (Ay et al., 2010;
Cummings & White, 2001; Venancio Rde et al., 2008). Thus, TrPDN—i.e. without injectate—is
becoming a popular therapeutic intervention among health professionals (Rodriguez-Mansilla et
al., 2016) and involves the insertion of thin monofilament (Cerezo-Tellez et al., 2016a) or hollow
bore needles (Kamanli et al., 2005) without delivery of any drug into a MTrP region. Current
systematic reviews report that direct MTrP needling is superior only to placebo for reducing pain
(Tough, 2011) at immediate (Kietrys et al., 2013), short-term (Boyles et al., 2015; Kietrys et al.,
2013; Liu et al., 2015) and medium-term (Liu et al., 2015) follow up. However, the effectiveness
of TrPDN over placebo for pain reduction in the long-term remains unknown (Kietrys et al.,
2013; Ong & Claydon, 2014). A recent systematic review of 19 randomized controlled trials
(RCTs) concluded that TrPDN may be effective for MTrP pain reduction across multiple body
regions and conditions, but no consensus was determined about the most effective needling
techniques for pain relief (Boyles et al., 2015). More specifically, some authors suggest that
TrPDN is most effective if a local twitch response (LTR) is elicited during the procedure (Hong,
1994b; Tekin et al., 2013). The LTR is characterized by a visible contraction of part of the taut
band in the involved muscle upon mechanical stimulation with needling or palpation to a
sensitive site in a MTrP region (Simons & Dexter, 1995). To elicit LTRs, many clinicians use a
fast-in and fast-out needling technique often referred to as “pistoning” in a fan or cone shape, for
the deactivation of MTrPs (Calvo-Lobo et al., 2015; Calvo-Lobo et al., 2016; Tellez-Garcia et
al., 2015). Notably, the use of needle pistoning, with the goal of eliciting single or multiple
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LTRs in the muscle belly, was a dominant theme in the methodology of the majority of studies
included in a recent systematic review that investigated the effectiveness of dry needling on
MTrP related pain (Morihisa et al., 2016). However, although needling (dry or wet) with the
production of LTRs has been shown to reduce MTrP related pain in the immediate, short, and
medium term, the long-term outcomes remain unknown. Furthermore, and more importantly,
whether needling with the elicitation of the LTR leads to superior outcomes for the reduction of
pain and disability when compared to needling interventions without the LTR remains largely
unexplored (Boyles et al., 2015; Gerber et al., 2015; Hong, 1994b; Kuan et al., 2012; Rha et al.,
2011; Tekin et al., 2013). In addition, the physiologic importance of the LTR during TrPDN
remains to be elucidated (Kuan et al., 2012), and no systematic reviews to date have provided
firm conclusions linking the LTR phenomenon directly to the positive clinical outcomes
experienced by patients with MPS following the use of TrPDN (Boyles et al., 2015; Cagnie et
al., 2015; Cummings & White, 2001; Kietrys et al., 2013). Given that other needling techniques
and manual therapies have shown efficacy in the management of myofascial pain and do not rely
on eliciting the LTR (Cagnie et al., 2012; Cagnie et al., 2015; Kostopoulos et al., 2008; Takano
et al., 2012), a more detailed investigation of the clinical relevance of the LTR seems
appropriate. Therefore, the purpose of this narrative review is to comprehensively investigate
the available literature to determine whether or not elicitation of the LTR is a necessary event
during dry or wet needling for the optimal short and/or long-term reduction of pain and disability
in patients with MPS.
Materials and Methods
Literature for this narrative review was sought that investigated the LTR phenomenon during
MTrP needling. Articles that provided insight on the neurophysiological mechanisms of MTrP
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needling and the LTR were included, along with studies that assessed the clinical relevance of
the LTR. The reference lists of these studies were also hand searched to identify other articles
relevant to the topic of the LTR. Importantly, individual studies that investigated the role of the
LTR as it pertains to the outcome of pain intensity with TrPDN or MTrP injection in human
subjects with MPS or other painful musculoskeletal conditions were included and listed in Table-
1. Consistent with our intent of performing a narrative review, the search was not limited to
randomized controlled trials, systematic reviews or meta-analyses. In addition, no restrictions
were placed on the date of article publication and only articles written in English were reviewed.
An electronic database search of PubMed, MEDLINE, Science Direct and Google Scholar were
searched up until October 2016 using the following terms; dry needling, injection, acupuncture
AND local twitch response, twitch response, myofascial pain, trigger point, mechanisms. All
articles that did not meet the above criteria were discarded
Results and Discussion
In this narrative review, 6 studies were identified that all investigated the clinical importance of
eliciting the LTR with MTrP injection or TrPDN as it pertains to the outcome of pain intensity
and they are summarized in Table-1. The studies included two randomized controlled trials
(Hong, 1994b; Tekin et al., 2013), one prospective, non-randomized, controlled, interventional
clinical study (Gerber et al., 2015), one case control study (Rha et al., 2011), one single-arm
cohort study (Kuan et al., 2012) and one quasi-experimental study (Koppenhaver et al., 2016).
Importantly, only a single study assessed the influence of eliciting the LTR on changes in
disability in addition to pain intensity (Koppenhaver et al., 2016)
.
All other studies referenced in
this review have relevance to the topic of MTrP injection or TrPDN for the management of MPS.
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Dry Needling Technique and The Localized Twitch Response
Empirical evidence suggests that eliciting multiple LTRs through mechanical stimulation of a
MTrP within a taut band is the most important factor for pain relief (Chou et al., 2014; Hong &
Simons, 1998; Hsieh et al., 2007). Some authors have suggested that the LTR during TrPDN is a
sensitive measure (Ge et al., 2008) and an objective confirmation (Simons & Travell, 1999) of
needle insertion into a trigger point, the location thought to have the greatest therapeutic effect
(Hong, 1994a). Developed by Hong (Hong, 1994a; Hong, 2013; Hong & Simons, 1998) and
now broadly used by practitioners for MTrP injection and TrPDN, the “multiple rapid insertion
technique” in a fan or cone shape is intended to provide high-pressure mechanical stimulation to
“sensitive loci”—i.e. sensitized afferent fibers—stimulating a subset of the α-motor neurons in
the spinal cord. The LTR is thought to subsequently break the vicious cycle of the MTrP circuit,
decreasing pain and disability (Audette et al., 2004; Chou et al., 2014; Hong & Simons, 1998;
Kuan et al., 2012). Importantly, the sensitive afferents that proliferate in the MTrP region (Hong
et al., 1997a; Meng et al., 2015b), mediate both the noxious input to the spinal cord (Meng et al.,
2015a) and the LTR induced through needling precise MTrP locations (Hong & Torigoe, 1994;
Simons et al., 1995). Resting pain intensity of the MTrP before injection has been found to be
highly correlated with LTR prevalence during injection (i.e. the higher the baseline pain
intensity, the more LTRs that were elicited), suggesting that the number of sensitized nociceptors
in the MTrP region is proportionate to the MTrP irritability (Kuan et al., 2012). Moreover, early
studies (Hong, 1994b; Hong et al., 1997b) also observed that the number of LTRs elicited was
directly proportional to subjective pain intensity before needling of MTrPs. Hong et al. (1997b)
further found the LTR was elicited in 100% of MTrPs treated with needling, while manual
palpation prior to injection was only able to elicit the LTR in 39% of the same MTrPs, a
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phenomenon which is likely due to the needle tip’s ability to directly stimulate sensitive loci
(Hong et al., 1997b).
Pathophysiology of the Localized Twitch Response
TrPDN to elicit the LTR is associated with neurophysiological responses (Cagnie et al., 2013)
that may contribute to its therapeutic effects. An earlier animal study showed that fast, rapid dry
needling resulted in more LTRs and end plate discharges when compared to slow needle
insertion (Chen et al., 2001). Consequently, suppression of motor end plate activity was more
pronounced with rapid dry needling to elicit multiple LTRs and may have led to more
acetylcholine depletion at the neuromuscular junction. Likewise, injection of botulinum
neurotoxin A into MTrPs has shown efficacy in treating myofascial pain (Zhou & Wang, 2014)
by blocking the release of acetylcholine from peripheral nerves, and decreasing motor endplate
activity (Kuan et al., 2002). Recently, motor end plate activity was normalized after eliciting
LTRs with dry needling to MTrPs of human subjects with trapezius MPS. In addition, the
improvement in pain intensity that occurred in the 20 subjects was accompanied by decreased
sympathetic hyperactivity measured through sympathetic skin response (Abbaszadeh-Amirdehi
et al., 2016a; Abbaszadeh-Amirdehi et al., 2016b). Importantly, another current study reported
eliciting the LTR with TrPDN in human subjects with MPS was more effective for reducing
surface EMG activity of the upper trapezius when compared to needling without LTRs provoked
(De Meulemeester et al., 2016). In a novel animal study by Hsieh et al. (2011), eliciting a LTR in
distal MTrPs suppressed motor end plate activity in a proximal but segmentally related muscle
(Hsieh et al., 2011). Thus, there seems to be a positive correlation between reduction in motor
end plate irritability and the LTR following TDN to either a local or remote MTrP (Chou et al.,
2011; Chou et al., 2009). Remarkably, motor endplate irritability in the MTrP region is strongly
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associated with pain intensity (Kuan et al., 2007) and TrPDN to evoke LTRs has been shown to
suppress motor endplate activity (i.e. deplete acetylcholine levels) and decrease MTrP pain
simultaneously (Chou et al., 2011). However, underlying pathologies of non-muscular origin
such as facet joint dysfunction (Hong, 2006; Tsai et al., 2009) may contribute to MTrP
formation. Moreover, facet injections (Huang et al., 2014; Tsai et al., 2009) and spinal
manipulation (Ruiz-Saez et al., 2007) have been shown to decrease endplate activity and pain,
respectively, related to trigger points. Additionally, alterations in the visco-elastic properties of
fascia (Stecco et al., 2013) and biomechanical deficiencies (Gerwin, 2001) have also been linked
with the formation and propagation of MTrPs. Thus, the LTR may lead to short term pain relief
by reducing muscle hyperexcitability, but long-term outcomes will likely not be achieved if the
underlying etiology of the condition is something other than muscle tissue (Hong, 2006).
TrPDN to MTrPs has been shown to increase B-endorphins (Hsieh et al., 2016; Hsieh et al.,
2012) and decrease CGRP and SP when measured after the occurrence of a LTR (Shah et al.,
2008; Shah & Gilliams, 2008; Shah et al., 2005). However, the physiologic mechanism
responsible for these biochemical changes following the LTR remains unknown (Kuan et al.,
2012). On the other hand, the LTR may be unrelated to changes in opioids, CGRP and SP.
Instead, TrPDN may simply cause vasodilation, resulting in the delivery of opioid producing
leukocytes and “washing out” sensitizing substances such as CGRP and SP (Shah & Gilliams,
2008). Moreover, dry needling has been shown to elicit increases in local circulation near the site
of needle insertion in the absence of a LTR (Ohkubo et al., 2009; Sandberg et al., 2005;
Sandberg et al., 2004). Cagnie et al. (2012) reported local blood flow in the upper trapezius was
72% higher than baseline levels 15 minutes after exposure to dry needling in healthy subjects, a
result that did not require a LTR (Cagnie et al., 2012). In other studies, blood flow increases with
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needling in a dose dependent manner and remains elevated for 60 minutes without the report of a
LTR (Shinbara et al., 2008).
Interestingly, studies from the acupuncture literature report an initial increase of CGRP and SP
after needling in the absence of a LTR (Butts et al., 2016; Wu et al., 2015). The added CGRP
may initiate a cascade of vasodilators, to include nitric oxide, which may lead to a washout effect
(Shinbara et al., 2013, 2015). Alternatively, the CGRP and SP may work to provide negative
feedback onto autoreceptors, ultimately decreasing the release of CGRP and SP (Zhang et al.,
2012). There is also evidence that the simultaneous release of SP may work to counter
peripheral levels of CGRP (Zijlstra et al., 2003). The latter explanation is particularly
interesting, as CGRP has been shown to propagate inflammation in high quantities but provide
potent anti-inflammatory actions in low quantities (Zijlstra et al., 2003). In this case, leaving
needles in situ with intermittent stimulation via winding or electric stimulation may be more
advantageous than TrPDN with a LTR, as it may facilitate continuous low levels of SP and
CGRP over time, thereby leading to lasting reduction of peripheral pain (Butts et al., 2016).
Clinical Relevance of The Localized Twitch Response
According to a recent narrative review, there is a sizeable consensus that elicitation of a LTR
provides greater immediate and long-term pain relief with needling therapy than no LTR (Shah
et al., 2015). However, this assumption is based on very limited research and relies
predominantly on clinical observation. Ga et al. (2007a, 2007b, 2007c) conceded that the LTR
experienced by the majority of subjects over 3 treatments of MTrP needling, likely contributed to
positive clinical outcomes (Ga et al., 2007a, b; Ga et al., 2007c). While this is consistent with
other recent studies reporting a high occurrence of LTRs in subjects treated with TrPDN
(Cerezo-Tellez et al., 2016b; Ma et al., 2010), the significant reductions in pain observed in the
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treatment groups were not directly compared to a group where needling was performed without
inducing a LTR. In fact, few studies have isolated elicitation of the LTR during TrPDN as a
variable that is more beneficial than not eliciting one in the treatment of trigger points for MPS
or other conditions (See Table-1)(Boyles et al., 2015). An earlier review by Cummings et al.
(2001) reported that only 1 out of 23 studies mentioned eliciting the LTR making it difficult to
draw conclusions of its clinical relevance (Cummings & White, 2001). In a more recent
systematic review, Cagnie et al. (2015) further reported a lack of clarity in the description of
TrPDN technique across 8 studies, making it difficult to determine if the LTR contributes to
TrPDN success (Cagnie et al., 2015). Similarly, Kietrys et al. (2013) could not clarify if eliciting
the LTR was a necessary component of TrPDN in 8 of 12 studies that treated upper quarter
myofascial pain (Kietrys et al., 2013). While Boyles et al. (2015) included 7 of 15 studies that
described eliciting a LTR during TrPDN for multiple body regions, few studies reported if or
how often LTRs were evoked during treatment. Thus, no firm conclusions can be made
concerning the importance of the LTR during TrPDN to treatment outcomes (Boyles et al.,
2015).
A number of recent studies that have yet to be included in current systematic reviews further
challenge the assumption that the LTR is necessary for effective TrPDN. Gerber et al. (2015)
and Suh et al. (2014) found no correlation between LTR occurrence during TrPDN of the upper
trapezius and brachialis muscles, respectively, and pain reduction or treatment success rate
(Gerber et al., 2015; Suh et al., 2014). Koppenhaver et al. (2016) also studied the LTR elicited
during TrPDN to the lumbar multifidus muscle at the L3, L4, and L5 spinal levels bilaterally in
66 subjects with low back pain to determine if it related to changes in pain, disability and muscle
function. Importantly, the LTRs elicited on the most painful side and vertebral level in 53% of
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subjects were unrelated to reductions in pain and disability at immediate and 1 week follow up
and did not lead to lasting change in muscle function. Furthermore, the authors concluded that
the LTR should not be considered necessary for successful TrPDN (Koppenhaver et al., 2016).
In another recent study, 3 weekly sessions of TrPDN were provided to 56 patients with neck or
shoulder girdle pain and A-MTrPs in the upper trapezius with the aim of eliciting a LTR.
Subsequently, the authors report 41 positive responders with a change in MTrP status from
active to latent or no palpable nodule and a clinically relevant improvement on the VAS (Gerber
et al., 2015), which persisted at the 6-week follow-up (Gerber et al., 2016). Interestingly, the
elicitation of the LTR failed to distinguish responders from non-responders, and the occurrence
of the LTR did not correlate with changes in pain (Gerber et al., 2015). Lim et al. (2008) further
reported that 69% of subjects had a 50% reduction in pain from baseline following TrPDN, even
though a low percentage of LTRs were actually elicited (Lim et al., 2008). Interestingly, Irnich et
al. (2002) found that TrPDN was not effective for reducing pain because of increased soreness
following the procedure, which may have resulted from the LTR (Irnich et al., 2002). However,
one study reported that occurrence of the LTR did not contribute to increased pain during MTrP
injection (Yoon et al., 2009). While Kuan et al. (2012) discovered that needle stimulation of
MTrPs can more frequently elicit LTRs when pain intensity and trigger point irritability (i.e.
number of sensitized nociceptors) is high, the degree of pain relief achieved with MTrP injection
to the upper trapezius was not strongly associated with the mean LTR prevalence in 72 subjects
with MPS. Rather, pain relief correlated with frequency of LTRs only when pain intensity was
exceptionally high (Kuan et al., 2012).
Place Table – 1 Summary of Clinical Studies Investigating The Local Twitch Response
Here
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The Localized Twitch Response and Short Term Pain Relief
Hong et al. (1994b) was the first to report significant pain reduction immediately post treatment
only when the LTR was elicited with no difference between the use of lidocaine injection or dry
needling in 41 of 58 patients with MPS (Hong, 1994b). However, the dry needling group
experienced significant pain increase from post treatment to 2-week follow up, and this was
reportedly due to the significant amount of post needling soreness. Thus, the improvements in
pain seen after the LTR with TrPDN in the Hong et al. (1994b) study were immediate only—i.e.
were not present at 2-week follow-up. In a study on 39-patients with MPS, TrPDN resulted in
significant reductions in pain and medication intake vs. non-penetrating sham needling, and
patients who experienced the LTR had better improvements in pain scores at 4 weeks (Tekin et
al., 2013). While subjects in the study who achieved a LTR had clinically meaningful reductions
in pain (Koppenhaver et al., 2016), long term outcomes were not measured (Tekin et al., 2013).
Using ultrasound guided MTrP injection, Rha et al. (2011) further investigated the clinical
importance of eliciting the LTR. While pain reduction was more significant in patients that were
LTR positive than LTR negative regardless of the muscle being treated (i.e. upper trapezius,
quadratus lumborum, or erector spinae), pain was only assessed immediately after the needling
procedure (Rha et al., 2011). Likewise, Bubnov and Wang (2013) found a significant correlation
between eliciting the LTR during TrPDN and pain relief (i.e. 50% reduction in pain on VAS) in
133 subjects with MTrPs, but only immediate and 24 hour follow up was observed (Bubnov &
Wang, 2013).
Post Needling Soreness
Significant adverse events secondary to TrPDN performed by trained physical therapists are rare
and have been calculated to be as low as 0.04% (Brady et al., 2014). However, the repeated
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needle insertion often required to elicit LTRs often leads to added micro trauma and post
needling soreness, which can increase patients’ resting pain levels instead of reducing them
(Campa-Moran et al., 2015; Irnich et al., 2002; Martín-Pintado-Zugasti et al., 2016). Post
needling soreness has been reported to occur in 100% of subjects receiving dry needling and
appears to be associated with levels of local hemorrhage and the number of needle insertions
(Hong, 1994b). Using the multiple rapid needling procedure on latent trigger points in 60
subjects, post needling soreness was present in 100% of subjects and resolved within 72 hours
(Martín-Pintado-Zugasti et al., 2016). Of importance, a higher number of needle insertions
during the “pistoning” procedure correlated with higher pain levels after needling treatment
(Martín-Pintado-Zugasti et al., 2016). Other studies reported that post-needling soreness
occurred in 50% or more (Ga et al., 2007a, b; Ga et al., 2007c; Martin-Pintado-Zugasti et al.,
2015) of subjects who received dry needling using multiple needle insertion method to elicit the
LTR, and the duration of soreness lasted more than 24 hours. A recent study reported 100% of
subjects treated with multiple rapid dry needle insertion to latent MTrPs in the upper trapezius
developed immediate post needling soreness that resolved within 72 hours (Martin-Pintado
Zugasti et al., 2014). It has been previously reported that the fast needle movement during the
multiple insertion method helps to prevent tissue injury (Hong, 2013), but skeletal muscle and
intramuscular nerve damage have been reported with use of this method (Domingo et al., 2013).
Domingo et al. (2013) reported that 1 session of 15 repeated needle punctures to healthy muscle
tissue in mice led to mechanical injury near the neuromuscular junction, a rapid inflammatory
reaction in the muscle and nerve terminal degeneration by Schwann cells within 24 hours.
Interestingly, re-innervation of end plates occurred within 3 days and skeletal muscle
regeneration was seen at 1 week (Domingo et al., 2013). However, in clinical practice dry
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needling is commonly used over several treatments, so it is uncertain if the normal processes of
muscle regeneration and nerve re-innervation occur after a series of needling treatments on
symptomatic individuals. In fact, a higher dosage of needling to MTrPs has shown to result in
overexpression of tumor necrosis factor (TNF-α) along the needle pathway and in the serum,
increased SP levels in the treated muscle and dorsal root ganglion, and reductions in endogenous
opioid levels (Hsieh et al., 2012), all evidence of skeletal muscle damage that may be
counterproductive for pain management.
Alternative Needling Techniques
Strong effects are observed when MTrPs are the focus of dry needle stimulation due to the
presence of sensitized nociceptors associated with the MTrP region (Hong et al., 1997a; Meng et
al., 2015a, b). The multiple rapid needle insertion technique—i.e. one needle with one insertion
point through the skin and into the target muscular trigger point, using repeated partial
withdrawals to the subcutaneous tissue and then re-insertion with a different angulation in a fan
or cone shape-- is proposed to elicit its effects mainly through “pricking” sensitized nociceptors
and inducing the LTR (Hong, 1994a). However, it remains unknown if this technique is superior
to other forms of needling for the treatment of pain associated with MTrPs. In fact, strong
stimulation may also be achieved through other forms of needle manipulation to bring about an
analgesic effect (Choi et al., 2013). For example, winding instead of pistoning the needle initiates
mechanotransduction of tissue, thereby activating TRPv1 receptors on peripheral nerve endings
(Wu et al., 2014). TRPv1 receptors are unique because they are one of the only peripheral
receptors activated by low pH, increased temperature and mechanical stimulation (Wu et al.,
2014). Recent evidence supports manually inserting and rotating needles every 5 minutes for a
total of 30 minute durations leads to intracellular Ca2+ wave propagation and increases in
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extracellular ATP and adenosine for up to 60 minutes when measured by microdialysis
(Goldman et al., 2010; Takano et al., 2012). The accumulation of adenosine activates A1
adenosine receptors and provides a strong anti nociceptive effect via inhibition of adenylate
cyclase (Takano et al., 2012). The intracellular Ca2+ propagation also helps initiate rho kinase
mediated tissue remodeling and blocks pain at the level of the spine by stimulating glycinergic
and GABAergic interneurons (Butts et al., 2016; Goldman et al., 2013; Langevin et al., 2011;
Zhou et al., 2008). Importantly, insertion (and likely repeated insertion) of the needle was shown
to not be enough to activate TRPv1 receptors and initiate the analgesic cascade. Rather,
increases in extracellular ATP and adenosine were only possible when connective tissue was
coupled to the needle (i.e. mechanotransduction) via winding (Langevin, 2014). Furthermore,
elicitation of a LTR is not necessary for this effect. According to Langevin et al. (2001) the
mechanical stimulation induced by needle pistoning may be amplified when connective tissue is
first coupled to the needle by winding, thus strengthening the mechanical signals transmitted to
nearby or remote cells (Langevin et al., 2001). In fact, several studies have suggested enhanced
LTR occurrence using needle rotation together with repeated in-and-out needle insertion (i.e.
“screwing in-and-out technique”) during treatment of MTrPs (Chou et al., 2008; Chou et al.,
2011; Chou et al., 2009). Therefore, needle pistoning in the absence of winding may not be
justified to elicit mechanotransduction. Consistent with this finding, Zhang et al. (2012) reported
greater activation of C-fibers, distal superficial and deep mechanoreceptors and stretch receptors
with needle rotation compared to lifting, scraping, shaking, thrusting and flicking (Zhang et al.,
2012). Thus, based on the evidence to date, the production of single or multiple LTRs during
TrPDN seems to have poor correlation in the short-term, and no correlation for the long-term
outcomes of pain and disability in patients with neck, shoulder or low back pain; however, the
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benefits of needle manipulation via winding of connective tissue, rather than repeated pistoning
directly into a single muscular trigger point is well supported in the literature for both the short
and long-term reduction of pain and disability (Dunning et al., 2014).
Segmental Analgesia
TrPDN also helps elicit spinal segmental pain inhibitory effects (Mejuto-Vazquez et al., 2014;
Srbely et al., 2010) and descending pain control pathways (Niddam et al., 2007) that may not
rely on eliciting LTRs. Strong needle stimulation via winding stimulates the release endogenous
opioids, which is considered one of the most potent mechanisms for pain suppression in the
periphery and at the spinal cord level secondary to needling treatment (Chou et al., 2012; Zhang
et al., 2014). Hsieh et al. (2016) demonstrated that needling distal but segmentally related MTrPs
induced increases in enkephalin at the spinal dorsal horn and β-endorphin in the serum and
dorsal root ganglion neurons. In addition, endogenous opioids were markedly increased in the
proximal muscle in proportion to needle dosage (Hsieh et al., 2016). Most importantly, this
study used slow and gentle needle insertion with rotation to MTrPs during a 30 second period
and did not report eliciting a LTR (Hsieh et al., 2016). In clinical studies, deep needle stimulation
to muscular afferents at acupuncture points and MTrPs with needle rotation, not multiple rapid
insertions at the same entry point and with the same needle, demonstrated a superior treatment
effect that persisted at 3 month follow up compared to superficial needling in subjects with
chronic shoulder (Ceccheerelli et al., 2001) and lumbar myofascial pain (Ceccherelli et al.,
2002), respectively.
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Manual MTrP Therapy
In a recent study on 94 patients with chronic neck pain, TrPDN with LTRs and trigger point
manual release both resulted in significant reduction in pain without significant between group
differences (Llamas-Ramos et al., 2014). Notably, manual pressure release does not involve the
insertion of a needle or the elicitation of a LTR. Moreover, a recent study reported that manual
MTrP compression was more effective than massage and non-MTrP compression for subjects
with acute LBP. As in TrPDN with LTRs, the authors reported that the effects of MTrP
compression may involve increased blood flow and suppression of acetylcholine at the
neuromuscular junction (Takamoto et al., 2015), a finding that has been confirmed by a recent
micro dialysis study (Moraska et al., 2013). Moreover, ischemic compression of MTrPs has been
shown to result in a significant reduction of SEA in the absence of a LTR (Kostopoulos et al.,
2008).
Conclusion
Dry needling to elicit LTRs is a commonly used technique to treat MTrPs for the management of
MPS; however, based on the evidence to date, the production of single or multiple LTRs during
muscular TrPDN seems to have poor correlation in the short-term for the outcomes of pain and
disability in patients with neck, shoulder or low back pain. Furthermore, there are no studies with
long-term outcome data that have investigated the effect of, or need for, the LTR during TrPDN
or acupuncture in patients with MPS or any musculoskeletal disorder. Nevertheless, the benefits
of needle manipulation via needle rotation or winding of connective tissue, rather than repeated
pistoning directly into muscular trigger points, is well supported in the literature. In addition, the
number of needle insertions during “pistoning” at one insertion site appears to positively
correlate with levels of post-needling soreness, increased levels of inflammation within muscle
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fibers, and mechanical injury at or near the neuromuscular junction. In addition, TrPDN using
needle rotation (i.e. unidirectional or bidirectional winding) and manual MTrP techniques have
been shown to elicit neurophysiological responses that can positively alter the MTrP status and
reduce pain without the need for a LTR. Therefore, the LTR during TrPDN appears unnecessary
and may not be required for managing myofascial pain and may be unrelated to many of the
positive effects of dry needling. However, further investigation is required.
Conflicts of interest: None
Funding: This research did not receive any specific grant from funding agencies in the public,
commercial, or not-for-profit sectors.
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Table – 1 Summary of Clinical Studies Investigating The Local Twitch Response
Study Subjects Interventions Findings on LTR
Hong (1994b)
58 patients with UT
MPS
TrPDN or Lidocaine
MTrP injection into
UT MTrPs
Pain intensity was
significantly reduced
immediately after
TrPDN or MTrP
injection without
significant between
group differences if
LTR was elicited.
Minimal to no
treatment effects
observed without
eliciting the LTR.
Immediate and 2
week follow up.
Rha et al. (2011)
103 patients (41
with MTrPs in UT,
62 with MTrPs in
ES or QL
US guided MTrP
Injection to UT, ES
or QL
Pain reduction was
more significant
when LTR was
elicited for both
groups receiving
MTrP Injection of
UT, ES or QL.
Immediate follow
up.
Tekin et al. (2013)
39 patients with
MPS TrPDN of upper
quarter MTrPs or
sham TrPDN
Patients in TrPDN
group with LTR had
better reduction in
pain than those
without LTR. Follow
up at end of
treatment (4 weeks).
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Gerber et al. (2015)
56 subjects with
neck or shoulder
girdle pain and UT
MTrPs
TrPDN of UT
MTrPs
Elicitation of the
LTR did not
distinguish
responders from
non-responders.
Change in pain not
statistically
correlated with
eliciting the LTR.
Follow up at end of
treatment (3 weeks).
Kuan et al. (2012)
72 subjects with UT
MPS
MTrP Injection into
UT
Weak correlation
found between pain
relief after injection
and LTR prevalence
during injection.
Immediate follow
up.
Koppenhaver et al.
(2016)*
66 patients with
LBP
TrPDN to L3, L4,
L5 multifidus
muscles bilaterally
No between group
differences between
subjects
experiencing a LTR
and those without
LTR in pain
intensity or disability
on the ODI at
immediate or 1 week
follow up.
*Denotes studies that assessed the influence of the LTR on disability measures
QL = quadratus lumborum; UT = upper trapezius; ES = erector spinae; US = ultrasound
... Authors of previous research have stressed the importance of eliciting a LTR during TDN to ensure that the myofilament needle has come in contact with a myofascial trigger point. 56,57 While it is still unclear if the elicitation of one or multiple LTRs during the application of dry needling is essential for reductions in pain and disability in various patient populations, 58,59 the purpose of this study was to investigate the effects of TDN specifically to latent trigger points within the gluteus medius muscle. As such, it was critical that a LTR was elicited during the application of TDN to ensure that the needle had in fact come in contact with a latent trigger point. ...
... Even though strength was being assessed on the control side, participants reported an increased level of soreness on the side that they were lying on potentially due to the need for stabilization during testing. Post needling soreness is commonly reported following the application of TDN 58 and may have affected the participants' ability to generate force during their first MVIC break test trial on the control side in the SL0 position. ...
... Future research on this topic could include other types of dry needling including superficial dry needling techniques, which may make it easier to include sham needles as a true placebo, while also reducing the potential for post needling soreness. 58 While the side of dominance was recorded for each of this study's participants, it was not considered during statistical analysis outside of descriptive statistics for demographic information of the sample. Future studies may consider if side of dominance has an effect on the number of MTrPs found in the muscle tissue as well as study outcomes. ...
Article
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Background Latent trigger points have been identified as a source of impaired muscle function giving rise to a reduction in force production and alterations in muscle activation patterns and movement efficiency. There is limited investigation into the effectiveness of a treatment in reducing these clinical manifestations. Purpose To investigate whether the application of trigger point dry needling (TDN) to latent trigger points within the gluteus medius musculature affected strength measurements and muscle activation levels immediately following intervention. Design Quasi experimental, single group, pretest-posttest, randomized control study Methods A control and an intervention side were randomly assigned for each participant ( N = 39). Hand held dynamometer (HHD) force measurements and raw surface electromyography (sEMG) amplitude readings were recorded during maximal volitional isometric contractions of the gluteus medius in two separate positions before and after application of TDN. Comparison of within and between group data were conducted. Results A statistically significant interaction between time (pre-TDN to post-TDN) and groups (intervention side and control side), p < 0.001 was found for HHD measurements in both positions. Post hoc analysis revealed a statistically significant difference ( p < 0.001) for all comparisons in the side lying neutral (SL0) position, while statistically significant differences ( p < 0.001) were found for pre and post-TDN measurements within intervention side as well as between the intervention and control side for post-TDN measurements in the side lying internal rotation (SLIR) position. For sEMG amplitude measurements, statistically significant differences were found only in the SL0 position for within group comparisons on the intervention side ( p = 0.009) and for between group comparisons for post-TDN measurements ( p = 0.002). Conclusion Application of TDN to latent trigger points within the gluteus medius can significantly increase gluteus muscle force production immediately following intervention while reducing the level of muscle activation required during contraction. Level of Evidence Level 2
... Needle insertion was slow. Local twitch responses (LTRs) were not sought given the current debate in the literature as to whether DN and the commonly used pistoning technique, whereby the needle is moved in an up-and-down motion, may cause post-TX muscle soreness [36][37][38]. Likewise, eliciting LTR may be uncomfortable [39]. ...
... Likewise, eliciting LTR may be uncomfortable [39]. Finally, whether obtaining an LTR is necessary to obtain positive outcomes is under debate [37,39,40]. Considering these issues, seeking an LTR was deemed contraindicated to functional goal attainment for fear the patient may refuse the IMES TX if she experienced discomfort during or post-TX. ...
Article
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The patient was a 6-year-old child with spastic quadriplegic cerebral palsy (CP) categorized with the gross motor function classification system (GMFCS) as a level IV and a Modified Modified Ashworth Scale (MMAS) of 2 for the bilateral hamstring and hip adductor muscles, and 3 for the bilateral gastrocnemius muscles. This patient’s limited range of motion significntly affected the caregiver’s ability to perform activities of daily living (ADLs). Dry needling (DN) is considered a standard treatment (TX) when treating adults with poor range of motion. This article aims to place intramuscular electrical stimulation (IMES), the delivery of an electrical current through a monofilament needle into targeted trigger points (TrPs) within the context of treating children with spastic CP. Following IMES TXs over 32 months that totaled 12 left hamstring TXs, 13 right hamstring TXs, 13 hip adductor TXs, 21 left gastrocnemius TXs, and 18 right gastrocnemius TXs, the patient demonstrated an increase in passive range of motion (PROM) of the hamstring, hip adductors, and gastrocnemius muscles. These gains equated to ease in ADLs. Both the Pediatric Evaluation of Disability Inventory (PEDI, PEDI-Caregiver Assistance Scale) and the Goal Attainment Scale (GAS) demonstrated decreased caregiver burden. The child’s GMFCS level and the MMAS did not change. Further data collection related to treating children with spasticity using IMES is indicated to validate this type of TX with this patient population.
... It has been reported that DN can cause a relief in pain secondary to MTrPs by producing local twitch responses (LTRs) [23]. Many researchers [24][25][26] have found that the effects of DN generally stem from the mechanical disruption of the muscle fibres and nerve endings caused by the needle prick, and few researchers [27] claimed that an LTR is being evoked during the DN procedure. Additionally, recent research has shown that DN of the upper trapezius alleviates myofascial pain syndromes, particularly neck pain. ...
... Additionally, recent research has shown that DN of the upper trapezius alleviates myofascial pain syndromes, particularly neck pain. In the study by Perreault, Dunning [27], TrP-DN resulted in immediate pain relief and improved range of motion with a four-week follow-up. ...
Article
Full-text available
Background: This study aimed to determine the short-term effects of dry needling (DN) combined with a standard exercise program on pain and quality of life in patients with chronic mechanical neck pain (CMNP). Methods: Thirty-one patients with CMNP were randomly allocated to the experimental and control groups. The experimental group received DN and underwent a standard exercise program (one DN session and six exercise sessions) for two weeks, whereas the control group underwent the same exercise program alone for two weeks. The participants' scores in the Numeric Pain Rating Scale (NPRS), Neck Disability Index (NDI), Short Form-36 Quality of Life Scale (SF-36 QOLS), and Beck Depression Inventory (BDI) before and after the intervention were assessed. Results: The control and experimental groups' post-test NDI, NPRS, SF-36 QOLS, and BDI scores significantly differed from their baseline scores (p ≤ 0.05). The between-group comparison of the post-test scores using Wilcoxon rank-sum test revealed no significant differences between the NDI, NPRS, BDI, and SF-36 QOLS scores of both groups (p ≥ 0.05). Conclusions: One session of trigger point DN (TrP-DN) with exercise and exercise alone showed the same pain and quality-of-life outcomes after a two-week intervention. We did not recognise TrP-DN as an efficient intervention, not because we obtained evidence that it is ineffective, but because there were inadequate high-quality studies on the subject and unavailable data on the minimum quantity of injections required for better DN outcomes in CMNP patients.
... When DN is applied directly into MTrPs, it consists of inserting a fine needle without medication into the skin, subcutaneous tissues, and muscle for eliciting LTR and disrupting mechanically MTrPs [16]. This technique should be differentiated from wet needling or injection, which uses an additional injection of analgesic substances, such as lidocaine, when performing the needling [17,18]. Among the different modalities of DN applied to the MTrPs, the most widely used is the "fast-in fast-out" or "pistoning" modality, which consists of repeated and fast entry of the needle into the MTrPs area in a fan or cone shape to elicit LTR [18]. ...
... This technique should be differentiated from wet needling or injection, which uses an additional injection of analgesic substances, such as lidocaine, when performing the needling [17,18]. Among the different modalities of DN applied to the MTrPs, the most widely used is the "fast-in fast-out" or "pistoning" modality, which consists of repeated and fast entry of the needle into the MTrPs area in a fan or cone shape to elicit LTR [18]. ...
Article
Full-text available
This study aims to analyze the effects of Dry Needling (DN) for the release of myofascial trigger points (MTrPs) in the triceps surae muscles (TSM). A systematic review was performed up to February 2022 in PubMed, PEDro, Scopus, CENTRAL, and Web of Science. Selection criteria were studies involving subjects older than 18 years presenting MTrPs in the TSM, without any concomitant acute or chronic musculoskeletal conditions; DN interventions applied to the MTrPs of the TSM; and results on pain, range of motion (ROM), muscle strength, muscle stiffness, and functional outcomes. The PEDro scale was used to assess the methodological quality of the studies, and the Risk of Bias Tool 2.0 to assess risk of bias. A total of 12 studies were included in the systematic review, involving 426 participants. These results suggest that DN of MTrPs in TSM could have a positive impact on muscle stiffness and functional outcomes. There are inconclusive findings on musculoskeletal pain, ROM, and muscle strength. Significant results were obtained in favor of the control groups on pressure pain thresholds. Despite the benefits obtained on muscle stiffness and functional performance, the evidence for the use of DN of MTrPs in the TSM remains inconclusive.
... For example, Hong [18] described a 'fast in and fast out' technique to elicit a local twitch response (LTR). While this technique is likely the most widely implemented, the literature is controversial regarding its use [23] and the importance of eliciting an LTR [23]. Furthermore, there is a lack of literature investigating DN dosage [24] or comparing different techniques [15,25,26]. ...
... For example, Hong [18] described a 'fast in and fast out' technique to elicit a local twitch response (LTR). While this technique is likely the most widely implemented, the literature is controversial regarding its use [23] and the importance of eliciting an LTR [23]. Furthermore, there is a lack of literature investigating DN dosage [24] or comparing different techniques [15,25,26]. ...
Article
Objectives: Examine: (1) whether variability in dry needling (DN) dosage affects pain outcomes, (2) if effect sizes are clinically important, and (3) how adverse events (AE) were documented and whether DN safety was determined. Methods: Nine databases were searched for randomized controlled trials (RCTs) investigating DN in symptomatic musculoskeletal disorders. Methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) scale. Included RCTs met PEDro criteria #1 and scored > 7/10. Data extraction included DN dosage, pain outcome measures, dichotomous AE reporting (yes/no), and AE categorization. Clinically meaningful differences were determined using the minimum clinically important difference (MCID) for pain outcomes . Results: Out of 22 identified RCTs, 11 demonstrated significant between-group differences exceeding the MCID, suggesting a clinically meaningful change in pain outcomes. Nine documented whether AE occurred. Only five provided AEs details and four cited a standard means to report AE. Discussion: There was inconsistency in reporting DN dosing parameters and AE. We could not determine if DN dosing affects outcomes, whether DN consistently produces clinically meaningful changes, or establish optimal dosage. Without more detailed reporting, replication of methods in future investigations is severely limited. A standardized method is lacking to report, classify, and provide context to AE from DN. Without more detailed AE reporting in clinical trials investigating DN efficacy, a more thorough appraisal of relative risk, severity, and frequency was not possible. Based on these inconsistencies, adopting a standardized checklist for reporting DN dosage and AE may improve internal and external validity and the generalizability of results.
... There is a statistically signi cant association with a chi-square, the higher the number of LTRs with the higher the percentage of subjects in whom their neck pain is reproduced (p<0.05) but there is no association that for more LTRs there is a greater improvement, higher LTRs also occur more where there is an active trigger point than latent but that is not related to a greater improvement either. The production of single or multiple LTRs during muscular MTrP DN seems to have poor correlation in the short-term for the outcomes of pain and disability in patients with neck pain (46). The twitch response during dry needling might be clinically relevant, but should not be considered necessary for successful treatment (32). ...
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The purpose was to determine the efficacy of deep dry needling (DDN) applied on an active myofascial trigger point (MTrP) versus a latent-MTrP versus a non-MTrP location, on pain reduction and cervical disability, in patients with chronic neck pain. A randomized, double-blind clinical trial design was used. A sample of 65 patients was divided into non-MTrP-DDN, active-MTrP-DDN and latent-MTrP-DDN groups. The visual analog scale (VAS), reproduction of the patient’s pain, number of local twitch responses, pressure pain threshold (PPT) and Neck Disability Index (NDI) were assessed before, during and after the intervention and up to 1 month post-intervention. The active-MTrP-DDN-group reduced pain intensity more than non-MTrP-DDN-group after a week and a month (p<0.01). Active-MTrP-DDN-group showed the greatest improvement in tibialis muscle PPT. An association was found with a higher percentage of subjects in whom their neck pain was reproduced when the active-MTrP (77.3%) and the latent-MTrP (81.8%) were treated. The application of DDN on an active-MTrP in the upper trapezius muscle shows greater improvements in pain intensity after one week and one month post-intervention, as well as lesser improvement in PPT in the tibialis muscle, compared to DDN applied in latent-MTrPs or outside of MTrPs in patients with neck pain
... This may have been due to differences in the application of the needling method. It is very important for the physician to get the muscle relaxation response known as twitch while needling, because twitch response is associated with anti-nociception and factors related to tissue repair and remodeling [29]. In a study in 2006 comparing the effects of laser therapy and trigger point injection in the treatment of MPS, 43 patients were divided into two groups. ...
Article
Full-text available
Myofascial pain syndrome (MPS) is a very common disease in the population that seriously affects quality of life. Although many treatment modalities are used, there is still no common protocol. The aim of this study was to compare the effectiveness of high-intensity laser therapy (HILT) and dry needling options. This prospective study included 108 patients with neck and/or upper back pain, diagnosed with MPS, who were randomly separated into 3 groups: the exercise group, the exercise + HILT group (HILT group), and the exercise + dry needling group (needling group). The visual analog scale (VAS), neck disability index (NDI), short form-36 (SF-36) scores, and neck range of motion (ROM) values of the patients before and after treatment were recorded and compared between the groups. In all 3 groups, the VAS and NDI scores decreased and ROM levels increased after treatment. The results in the HILT and needling groups were statistically significantly better than those of the exercise group (p < 0.05).The addition of HILT and dry needling to exercises is seen as a more successful treatment option to reduce pain in MPS. Clinical trial registration number: NCT05078333.
Article
Objective: The purpose of this study was to determine the immediate effects of adding dry needling (DN) to thoracic spine manipulation and neck-specific exercise in individuals with neck pain. Methods: Forty-two participants with neck pain were randomized to either the true (n = 21) or sham (n = 21) DN groups, receiving treatment on the initial visit and 2 to 3 days later. Outcomes were assessed on day 1, both at baseline and immediately after the initial treatment, at the second treatment 2 to 3 days later, and at the final visit 5 to 7 days after visit 2. Primary outcomes were Neck Disability Index (NDI) (0-50) and current pain via numeric pain rating scale (0-10). Secondary outcomes were cervical range of motion, pain pressure threshold, and global rating of change. Results: Repeated measures analysis of covariance with baseline value as covariate revealed no significant difference in NDI scores at either follow-up time point with adjusted mean differences (95% confidence interval) of -0.11 (-2.70 to 2.48) and 0.31 (-1.96 to 2.57). There were no between-group differences in pain at any time point via Independent-Samples Median Test (P value range of .54-1.0). Secondary outcome measures were similarly not statistically different between groups except for immediate improvements in rotation to the side opposite of pain, which favored DN, with an adjusted mean difference (95% confidence interval) of 7.85 (3.54-12.15) degrees. Conclusion: The addition of DN to thoracic spinal manipulation and neck-specific exercise did not affect improvements in NDI score or numeric pain rating scale but showed an increase in cervical range of motion.
Article
Objective: The authors of this systematic review with meta-analysis evaluated the evidence for the effectiveness of various applications of dry needling (DN) combined with other conservative treatments for subacromial pain syndrome (SAPS). Methods: Six databases (PubMED, CINALH, Biosis, Web of Science, SPORTDiscus and Cochrane Central register of Controlled Trials) were searched following PROSPERO registration. The authors included randomized clinical trials investigating clinical effects of DN in combination with other conservative interventions for SAPS. Outcomes included pain and/or disability. Results: Eight studies were selected. All eight studies involving 10 comparisons were included in the analyses (N-538). Random-effects model analyzed between-group effects. Dry needling performed in combination with other conservative interventions produced favorable outcomes at all time points for pain and disability. Standard mean difference ranged from -0.57 (moderate) to -1.29 (large) for pain and -0.69 (moderate) to -1.07 (large) for disability favoring groups receiving DN in addition to conservative treatment. Four of the eight studies were rated as unclear or high risk of bias. Conclusion: The meta-analysis suggests various applications of DN performed with other conservative interventions are more effective than conservative treatment alone for reducing pain and disability in patients with SAPS. Direct comparison studies are needed to determine if one application of DN is superior to another. Prospero registration: CRD42022303063.
Article
Purpose: This article investigates the immediate effects of a dry needling (DN) puncture on the viscoelastic properties (tone, stiffness, elasticity) of a trigger point (TP) in the infraspinatus muscle in non-traumatic chronic shoulder pain. Method: Forty-eight individuals with non-traumatic chronic shoulder pain were recruited. The presence of a TP in the infraspinatus muscle was confirmed by a standardized palpatory exam. The viscoelastic properties were measured with a MyotonPRO device at baseline (T1), immediately after DN (T2), and 30 minutes later (T3). A DN puncture was applied to the TP to obtain a local twitch response while performing the technique. Results: Analyses of variance showed significant decreases in tone ( p < 0.001) and stiffness ( p = 0.003) across time after the DN technique. Post hoc tests revealed a significant reduction in tone and stiffness from T1 to T2 ( p ≤ 0.004) and no significant changes from T2 to T3 ( p ≥ 0.10). At T3, only stiffness remained significantly lower compared to T1 ( p = 0.013). Conclusions: This study brings new insights on the immediate mechanical effect of DN on tone and stiffness of TPs. Whether these effects are associated with symptom improvement and long-term effects still needs to be verified.
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Background Active myofascial trigger points (MTrPs) are major pain generators in myofascial pain syndrome. Dry needling (DN) is an effective method for the treatment of MTrPs. Objective To assess the immediate neurophysiological and clinical effects of DN in patients with upper trapezius MTrPs. Methods This was a prospective, clinical trial study of 20 patients with upper trapezius MTrPs and 20 healthy volunteers (matched for height, weight, body mass index and age), all of whom received one session of DN. Primary outcome measures were neuromuscular junction response (NMJR) and sympathetic skin response (SSR). Secondary outcomes were pain intensity (PI) and pressure pain threshold (PPT). Data were collected at baseline and immediately post-intervention. Results At baseline, SSR amplitude was higher in patients versus healthy volunteers (p<0.003). With respect to NMJR, a clinically abnormal increment and normal reduction was observed in patients and healthy volunteers, respectively. Moreover, PPT of patients was less than healthy volunteers (p<0.0001). After DN, SSR amplitude decreased significantly in patients (p<0.01), but did not change in healthy volunteers. A clinically important reduction in the NMJR of patients and increment in healthy volunteers was demonstrated after DN. PPT increased after DN in patients, but decreased in healthy volunteers (p<0.0001). PI improved after DN in patients (p<0.001). Conclusions The results of this study showed that one session of DN targeting active MTrPs appears to reduce hyperactivity of the sympathetic nervous system and irritability of the motor endplate. DN seems effective at improving symptoms and deactivating active MTrPs, although further research is needed. Trial registration number IRCT20130316128.
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Background: Dry needling is an effective treatment for reducing pain associated with active myofascial trigger points (aMTrPs) in the short term. The duration of the benefits of this treatment have not been fully assessed. Objective: This study attempts to determine whether the benefits of dry needling (DN) of a-MTrPs are sustained 6 weeks post-treatment. Design: Follow-up of a prospective study SETTING: University PARTICIPANTS: Forty-five subjects (13 males) with cervical pain > 3 months and a-MTrPs in the upper trapezius who completed 3 DN treatments, evaluated 6-weeks post-treatment. Interventions: None Main Outcome Measures: PRIMARY OUTCOMES: Changes from baseline to follow-up in scores for the verbal analogue scale (VAS), Brief Pain Inventory (BPI), and MTrP status. MTrPs were rated: active (spontaneously painful), latent (painful only on compression) and non-palpable nodule. Responders: patients whose MTrP status changed from active to latent or non-palpable nodule (resolved). Secondary outcomes: Pain pressure threshold (PPT), Profile of Mood States, Oswestry Disability Index (ODI), SF-36, Cervical Range of Motion. Results: Pain measures remained significantly improved 6 weeks post-treatment (p<.003), as did the SF-36 physical functioning score (.01) and ODI (p=.002). Side bending and PPT for subjects with unilateral MTrPs had sustained improvement (p=.002). The number of subjects with sustained MTrP response at 6 weeks was significant (p<.001). Comparing responders to non-responders, change in VAS and BPI were statistically significant (p = .006, p=.03), but PPT was not. Patients with higher baseline VAS have higher risk of not responding to DN, those with a greater drop in VAS from baseline have a higher probability of sustained response. One unit decrease in VAS at baseline results in a 6.3-fold increase in the odds of being a responder versus a non-responder (p = .008). Conclusions: There is sustained reduction of pain scores after completion of DN, which is more likely with a greater drop in VAS. Patients with higher baseline VAS are less likely to respond to DN. Early intervention toward significant pain reduction is likely to be associated with sustained clinical response.
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There are a number of biochemical, biomechanical, endocrinological and neurovascular mechanisms underpinning the anti-nociceptive and anti-inflammatory effects of dry needling (DN). While myofascial trigger points likely play a role in peripheral pain, a diagnostic tool for localizing them has not been validated, and DN studies that have targeted trigger points to elicit localized twitch responses have reported mixed results. Therefore, the mechanism responsible for DN-mediated analgesia may be more complicated. DN activates opioid-based pain reduction, mediated by endogenous cannabinoids and the sympathetic nervous system, and non- opioid pain relief via serotonin and norepinephrine from the brain stem. DN also triggers the hypothalamic-pituitary-adrenal axis centrally and the corticotropin releasing hormone-proopiomelanocortin-corticosteroid axis locally to inhibit cox-2, reducing inflammatory cytokines. Recent studies demonstrate that DN combined with mechanical and/or electric stimulation may reverse PKC-mediated peripheral hyperalgesic priming by normalizing nociceptive channels, to include TRPV, ASIC, TTX and P2X/Y. Electric DN (EDN) stimulates immune cells, fibroblasts and keratinocytes to release CGRP and substance-P, altering the stimulation of TTX receptors to reverse hyperalgesia. It also encourages the supraoptic nucleus to release oxytocin to quiet ASIC receptors peripherally and stimulate opioid interneurons spinally. Moreover, EDN inhibits ERK1/2 kinase pathways of inflammation in the spinal cord and stimulates Aδ fibers and N/OFQ to reverse C-fiber mediated central changes. Mechanotransduction of fibroblasts and peripheral nerves via TRPV1 and P2X/Y-mediated intracellular Ca2+ wave propagation and subsequent activation of the nucleus accumbens inhibits spinal pain transmission via glycinergic and opioidergic interneurons. The increased ATP is metabolized to adenosine, which activates P1 purinergic receptors, events considered key to DN analgesia and rho kinase-based tissue remodeling. Mechanotransduction-mediated release of histamine further explains analgesia secondary to needling points distal to pain. DN-mediated analgesia is dependent on a number of synergistic physiologic events involving biochemical and mechanical processes in neural, connective and muscle tissue.
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Objective: To summarize the literature about the effectiveness of dry needling (DN) on relieving pain and increasing range of motion (ROM) in individuals with myofascial pain syndrome (MPS). Methods: Papers published from January 2000 to January 2013 were identified through an electronic search in the databases MEDLINE, Dialnet, Cochrane Library Plus, Physiotherapy Evidence Data-base (PEDro) and Spanish Superior Council of Scientific Research (CSIC). The studies included were randomized controlled trials written in English and/or Spanish about the effectiveness of DN on pain and ROM in individuals with MPS. Results: Out of 19 clinical trials that were potentially relevant, a total of 10 were included in the Meta-analysis. Regarding pain intensity reduction when measured before and immediately after the intervention, DN achieved improvement compared with the placebo treatment [d = - 0.49; 95% CI (- 3.21, 0.42)] and with the control group [d = - 9.13; 95% C (- 14.70, - 3.56)]. However, other treatments achieved better results on the same variable compared with DN, considering the measurements for pre-treatment and immediately after [d = 2.54; 95% CI (- 0.40, 5.48)], as well as the pre-treatment and after 3-4 weeks [d = 4.23; 95% CI (0.78, 7.68)]. DN showed a significantly increased ROM when measured before the intervention and immediately after, in comparison with the placebo [d = 2.00; 95% C (1.60, 2.41)]. However, other treatments achieved a significant better result regarding ROM when it was measured before the intervention and immediately after, as compared with DN [d = - 1.42; 95% CI (- 1.84, - 0.99)]. Conclusion: DN was less effective on decreasing pain comparing to the placebo group. Other treatments were more effective than DN on reducing pain after 3-4 weeks. However, on increasing ROM, DN was more effective comparing to that of placebo group, but less than other treatments.
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Objective: To investigate the relationship between dry needling-induced twitch response and change in pain, disability, nociceptive sensitivity, and lumbar multifidus muscle function, in patients with low back pain (LBP). Design: Quasi-experimental study. Setting: Department of Defense Academic Institution. Participants: Sixty-six patients with mechanical LBP (38 men, 28 women, age: 41.3 [9.2] years). Interventions: Dry needling treatment to the lumbar multifidus muscles between L3 and L5 bilaterally. Main outcome measures: Examination procedures included numeric pain rating, the Modified Oswestry Disability Index, pressure algometry, and real-time ultrasound imaging assessment of lumbar multifidus muscle function before and after dry needling treatment. Pain pressure threshold (PPT) was used to measure nocioceptive sensitivity. The percent change in muscle thickness from rest to contraction was calculated to represent muscle function. Participants were dichotomized and compared based on whether or not they experienced at least one twitch response on the most painful side and spinal level during dry needling. Results: Participants experiencing local twitch response during dry needling exhibited greater immediate improvement in lumbar multifidus muscle function than participants who did not experience a twitch (thickness change with twitch: 12.4 [6]%, thickness change without twitch: 5.7 [11]%, mean difference adjusted for baseline value, 95%CI: 4.4 [1 to 8]%). However, this difference was not present after 1-week, and there were no between-groups differences in disability, pain intensity, or nociceptive sensitivity. Conclusions: The twitch response during dry needling might be clinically relevant, but should not be considered necessary for successful treatment.
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Introduction: Dry needling (DN) is a widely used in treatment of myofascial trigger points (MTrPs). The purpose of this pretest-posttest clinical trial was to investigate the neurophysiological and clinical effects of DN in patients with MTrPs. Methods: A sample of 20 patients (3 man, 17 women; mean age 31.7 ± 10.8) with upper trapezius MTrPs received one session of deep DN. The outcomes of neuromuscular junction response (NMJR), sympathetic skin response (SSR), pain intensity (PI) and pressure pain threshold (PPT) were measured at baseline and immediately after DN. Results: There were significant improvements in SSR latency and amplitude, pain, and PPT after DN. The NMJR decreased and returned to normal after DN. Conclusions: A single session of DN to the active upper trapezius MTrP was effective in improving pain, PPT, NMJR, and SSR in patients with myofascial trigger points. Further studies are needed.
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Background and aim Acupuncture applied at myofascial trigger points (MTrPs) of distant anatomical regions, to reduce pain in a patient's area of primary complaint, is one strategy that is available to manage myofascial pain. However, the endogenous opioid-mediated analgesic mechanism of distant acupuncture associated with pain control is still unclear. This aims of this study were to evaluate the changes in enkephalin and β-endorphin in serum, spinal cord, dorsal root ganglion (DRG) and muscle induced by acupuncture at distant myofascial trigger spots (MTrSs, similar to human MTrPs) in rabbits, to explore its underlying remote analgesic mechanism. Methods Acupuncture at MTrSs of a distant muscle (gastrocnemius) was performed either for one session or five daily sessions in rabbits. The levels of enkephalin and β-endorphin in proximal muscle (biceps femoris), serum, DRGs and spinal cords (L5-S2) were then determined by immunoassay immediately and 5 days after treatment. Results Immediately after treatment, acupuncture comprising both one dose and five doses significantly enhanced spinal enkephalin expression and serum β-endorphin levels (p<0.05). However, only five-dose acupuncture significantly enhanced the β-endorphin levels in the biceps femoris and DRGs (p<0.05), while 1-dose acupuncture did not (p>0.05). Furthermore, 5 days after treatment, significantly increased levels of spinal enkephalin and serum β-endorphin persisted in animals that received 5-dose acupuncture (p<0.05). Conclusions This study demonstrates that interactions within the endogenous opioid system may be involved in the remote effects of acupuncture treatment and could be a potential analgesic mechanism underlying MTrP pain management.