6. Goals of Discussion
• Review the diagnostic criteria for myofascial pain and
demonstrate the referral patterns of common myofascial
trigger points (MTrPs)
• Examine the unique neurobiology of muscle pain
• Discuss the dynamic interplay of muscle nociceptors and
endogenous biochemicals in the initiation, amplification
and perpetuation of peripheral and central sensitization
• Demonstrate that an active myofascial trigger point (MTrP)
in the upper trapezius has elevated levels of inflammatory
mediators, neuropeptides, and cytokines, etc. – substances
known to be associated with persistent pain states,
sensitization and inflammation
7. Goals of Discussion
• Introduce novel applications of ultrasound
techniques to visualize MTrPs, measure their
stiffness properties and local blood flow
• Demonstrate that MTrPs in the upper trapezius are
stiffer than surrounding tissue and that active MTrPs
can be distinguished from latent MTrPs by their
high-resistance blood flow
8. Myofascial Trigger Points
Hans-Werner Weisskircher
www.trigger-point.com
A Very Common, Complex and Overlooked
Cause of Non-articular Musculoskeletal Pain
9. Essential Clinical Criteria for
Myofascial Pain
• Palpation of a taut band
• Exquisitely tender spot (a myofascial trigger point) in
the taut band
• Reproduction of the subject’s symptomatic pain
Gerwin et al. Interrater reliability in
myofascial trigger point examination.
Pain. 1997;69(1-2):65-73
Hans-Werner Weisskircher
www.trigger-point.com
10. Essential Clinical Criteria for
Myofascial Pain
• Palpation of a taut band
• Exquisitely tender spot (a myofascial trigger point) in
the taut band
• Reproduction of the subjects symptomatic pain
Gerwin et al. Interrater reliability in myofascial trigger point
examination. Pain. 1997;69(1-2):65-73
Courtesy Marta Imamura
11. Myofascial Trigger Points
2-5 areas in hard, palpable
bands of skeletal muscle:
Active – cause a clinical pain
complaint or other abnormal
sensory symptoms
Latent – show all the other
characteristics of active
MTrPs, except that they’re
pain free
Travell JG, Simons DG. Myofascial pain and
dysfunction: the trigger point manual.
Baltimore: Williams & Wilkins; 1992.
13. Muscle Pain, Inflammation, and Sensitization
Muscle
Injury Release of Inflammatory
mediators, Neuropeptides
and Cytokines
Courtesy Marta Imamura
14. Muscle Pain, Inflammation, and Sensitization
Muscle Sensitize wide dynamic range
Injury neurons and higher centers
leading to allodynia, hyperalgesia
and…
and…
Courtesy Marta Imamura
15. Muscle Pain, Inflammation, and Sensitization
… expansion of the receptive
field of pain and referral of pain
Courtesy Marta Imamura
16. Travell JG, Simons DG. Myofascial
pain and dysfunction: the trigger point
manual. Baltimore: Williams &
Wilkins; 1992.
17. Common Referral Diagnoses for Pain
Found to be of Myofascial Origin
• Angina Pectoris • Pectoralis Major
(atypical)
• Appendicitis • Lower Rectus
Abdominis
• Atypical Migraine • Sternocleidomastoid,
• Tension Headache Temporalis, Mastic.
• Occipital Headache Musc, Post. Cervicals,
Travell JG, Simons DG. Myofascial
pain and dysfunction: the trigger point
manual. Baltimore: Williams &
Wilkins; 1992.
18. “Since no specialty claims
skeletal muscle as their organ, it
is often overlooked”
David G. Simons, MD
19. Muscle – The “Orphan Organ”
• NO specialty claims muscle as its organ
Muscle is ½ of the body
No organized emphasis on muscle pain
(MTrP) research or student training
Clinicians focus primarily on treating the
SYMPTOMS of myogenic pain, not the
CAUSE of the pain (MTrPs)
20. Active MTrPs can only be diagnosed by
systematic palpation
Hans-Werner
Weisskircher
www.trigger-point.com
22. Palpation, Palpation, Palpation
• Careful palpation of the surface
of the body reveals distinct
differences in the quality and
density of the underlying tissue.
Many of these areas or points
will be tender:
• A Shi points in Traditional
Chinese Medicine
• Kori in Japanese system
• Muskelharten in German system
23. Nociceptor Function
• Encode Noxious Stimuli
• Possibly leading to pain
• Maintain Tissue Health
• Initiate and maintain reaction to injury
27. Muscle Pain is often Overlooked
“I’ll be “Ohhh,
Back!” my
Back!”
28. Unique Characteristics of Muscle Pain
• Aching, cramping pain, difficult to
localize and referred to deep and distant
somatic tissues
• Muscle pain activates unique cortical
structures
Svensson P et al. Cerebral processing of acute skin and muscle pain in humans. J
Neurophysiology July 1997; 78: 450-460.
• Inhibited more strongly by descending
pain-modulating pathways
XianMin Y, Mense S. Response Properties and descending control of rat dorsal
horn neurons with deep receptive fields. Neuroscience 1990; 39:823-831.
• Activation of muscle nociceptors is much more
effective at inducing neuroplastic changes in
dorsal horn neurons
Wall PD, Woolf CJ. J Physiol 1984 Nov;356:443-458.
30. Powerful Descending Inhibition on Muscle Pain
Fields HL, Basbaum AI: Central
nervous system mechanisms of
pain modualtion. In Textbook of
Pain; 1999:309-329.
31. Afferent Bombardment of Muscle Nociceptors:
2nd Messenger Cascades, Induction of Immediate Early
Genes and Protein Synthesis, Excitotoxicity and Cell Death
Activity Dependent Plasticity
Wall PD, Woolf CJ. Muscle but not cutaneous C-afferent input produces prolonged
increases in the excitability of the flexion reflex in the rat. J Physiol. 1984 Nov;356:443-58.
35. Characteristics of Muscle Nociceptor
Projections to Dorsal Horn
• REDUCED SPATIAL RESOLUTION
– Due to lower density of muscle sensory afferents
compared to the skin
• CONVERGENCE OF SENSORY INPUT
– Input from skin, bone, viscera, periosteum
36. Dorsal Horn Changes in Pathologic
Conditions – Central Sensitization
DIVERGENCE OF SENSORY INPUT
• Sustained noxious stimulation (of Group IV fibers
in muscle) leads to the opening of previously
ineffective connections in dorsal horn neurons
• Intramuscular injection of various biochemicals
(e.g., bradykinin, prostaglandins, serotonin, acidic
saline, etc.) activates muscle nociceptors and
causes allodynia and hyperalgesia
37. Expansion of Receptive Field by a
Painful Muscle Stimulus
Courtesy Jan Dommerholt
Biceps Femoris
Selected neuron responds
Hoheisel U, Mense S, Simons DG. Appearance of new receptive fields in
only to deep pressure in rat dorsal horn neurons following noxious stimulation of skeletal muscle: a
biceps femoris muscle model for referral of muscle pain? Neurosci lett 153:9-12, 1993
38. Expansion of Receptive Field by a
Painful Muscle Stimulus
Courtesy Jan Dommerholt
5 min after BK injection in TA, the selected neuron can
now be excited by additional RF’s located in deep Hoheisel U, Mense S, Simons DG.
muscle that normally have high threshold Neurosci lett 153:9-12, 1993
39. Expansion of Receptive Field by a
Painful Muscle Stimulus
Hoheisel U, Mense S, Simons DG.
Neurosci lett 153:9-12, 1993
40. Expansion of Receptive Field by a
Painful Muscle Stimulus
Hoheisel U, Mense S, Simons DG.
Neurosci lett 153:9-12, 1993
41. Expansion of Receptive Field by a
Painful Muscle Stimulus
Hoheisel U, Mense S, Simons DG.
Neurosci lett 153:9-12, 1993
42. Expansion of Receptive Field by a
Painful Muscle Stimulus
Hoheisel U, Mense S, Simons DG.
Neurosci lett 153:9-12, 1993
43. Expansion of Receptive Field by a
Painful Muscle Stimulus
Allodynia
(light pressure and muscle
movement)
Hyperalgesia
15 min after BK injection in the TA the selected neuron responds
to moderate (innocuous) pressure in its original receptive field -
Hoheisel U, Mense S, Simons DG
biceps femoris
Neurosci lett 153:9-12, 1993
44. Nociceptive Bombardment causes
Central Sensitization and Neuroplastic
Glutamate Substance P Changes in Dorsal Horn Neurons
54. Historical Context of Trigger Points
• Steindler coined the term “trigger points”
when he found he was able to relieve
sciatica by injecting Novocain into tender
points in muscles in the lumbar and gluteal
regions
• Travell added the term “myofascial” after
performing a biopsy of the infraspinatus
muscle and observed that pinching the
fasciae produced the same referral pattern
as the muscle
58. “Dry needling MTrPs and
eliciting LTRs is as effective as
lidocaine injection in inactivating
a MTrP and relieving pain”
Hong CZ. Lidocaine injection versus dry needling to
myofascial trigger point. The importance of the local twitch
response. Am J Phys Med Rehabil. 1994;73(4):256-63.
59. Recent studies comparing MTrP injections with a
syringe and MTrP needling with an acupuncture
needle showed that MTrP needling with an acup
needle does not cause more post-needling soreness
Ga H, Choi JH, Park CH, Yoon HJ. Acupuncture needling
versus lidocaine injection of trigger points in myofascial
pain syndrome in elderly patients - a randomised trial.
Acupunct Med. 2007 Dec;25(4):130-6.
Ga H, Koh HJ, Choi JH, Kim CH. Intramuscular and nerve
root stimulation vs lidocaine injection to trigger points in
myofascial pain syndrome. J Rehabil Med. 2007
May;39(5):374-8.
60. Trigger Point Needling:
Proper Technique to Elicit Local Twitch
Responses is Essential
Hong CZ Arch Phys Med Rehab 1994;73:256
Courtesy Joseph Audette
69. Microdialysis/Acupuncture
Needle – 30 Gauge Hypodermic
Delivery tubes
Fluid in
Fluid
out
Solute exchange
surface – dialyzer
membrane set 0.2
mm from the
needle tip
Courtesy Terry Phillips
70. Comparison of Needle Tips
25G syringe needle
32G acupuncture needle
Courtesy Terry Phillips
71. Comparison between a
Standard Acupuncture Needle and
our Needle/Probe
Needle/Probe
Acupuncture needle
Courtesy Terry Phillips
72. Comparison of Needle Tips
Rounded Sharp beveled
acupuncture needle hypodermic needle
tip pushes cells tip acts like a
aside rather than miniature scalpel
piercing them capable of piercing,
cutting and tearing
cells
Courtesy Terry Phillips
79. Design, Setting, and Patients
Three healthy subjects were selected to be in each of
three groups (total 9 subjects) based on history and
physical examination of upper trapezius:
• Group 1) Normal (no neck pain, no trigger point)
• Group 2) Latent (no neck pain, trigger point
present)
• Group 3) Active (neck pain present [< 3months],
trigger point present).
80. Initial Analyte Values in Trapezius
Analyte Active Latent Normal *P value
pH (pH units) 5.4 6.3 6.5 P<.03
Bradykinin (pm/l) 69 49.6 47.5 P<.01
NE (nmol/l) 3.1 2.0 1.8 P<.01
Serotonin (nmol/l) 6.6 4.7 4.1 P<.01
Substance P (pg/ml) 187 50 34 P<.01
CGRP (pg/ml) 172 37.4 25.5 P<.01
TNF-α (pg/ml) 173.5 26.5 21.2 P<.001
IL-1β (pg/ml) 133.7 19.5 17.7 P<.001
*Active > Latent, Normal (except pH)
81. 400
Concentration of Substance P over time
350
300
250
Active
I
p g /ml
200
I = SEE
150
100
Latent
50 I
I
Normal
0
0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48
Time
82. First Phase: What We’ve
Demonstrated
• Collect near real-time samples from soft tissue
with minimal system perturbation and without
harmful effects on subjects
• Proof-of-principle of the system’s ability to
distinguish among subjects who have clinically
distinct soft tissue findings
• Active MTrP in the upper trapezius has elevated
levels of inflammatory mediators (bradykinin,
protons, etc.), catecholamines (norepinephrine and
serotonin), neuropeptides (substance P, CGRP)
and pro-inflammatory cytokines (TNF-α, IL-1β)
Shah J, Phillips T, Danoff J, Gerber L. An in vivo microanalytical technique for measuring
the local biochemical milieu of human skeletal muscle. J Appl Physiol. 2005 99(5): 1977-84.
83. Purpose of Second Phase
1) Determine whether these findings are unique to
the upper trapezius when compared to a remote
uninvolved site in the medial gastrocnemius
muscle
2) Measure additional analytes (e.g., IL-6 and IL-8)
known to be associated with pain, inflammation
and intercellular signaling.
84. Design, Setting, and Patients
9 subjects, all of whom had no calf pain or calf
MTrPs, were divided into 3 groups based on the
following findings in the trapezius:
1) Active (painful MTrP present; 3 subjects)
2) Latent (non-painful MTrP present; 3 subjects)
3) Normal (no pain, no MTrP present; 3 subjects)
85. No
MTrP
3 Groups of Subjects with following findings in upper
Hans-Werner
trapezius muscle: Weisskircher
www.trigger-
1) Active MTrP, 2) Latent MTrP, 3) No MTrP point.com
86. Exclusion Criteria
• Fibromyalgia • Other concurrent pain
• Cervical radiculopathy syndromes
• Atypical facial neuralgia • Use of tobacco products
• History of previous trigger • Any aspirin within 3 days of
point injections in the needling
upper trapezius and upper • History of bleeding diatheses
medial gastrocnemius • Being on anticoagulation
• Knee pain therapy
• History of cervical spine or • An inordinate fear of needles
shoulder surgery • Lumbosacral radiculopathy
• On any medications
87. Procedure and Measures
Procedure :
Samples were obtained continuously from
the trapezius site at regular intervals for 14
minutes, and then from the upper medial
gastrocnemius site for 10 minutes.
Measures :
Levels of protons (H+), bradykinin, SP,
CGRP, serotonin, norepinephrine, TNF-α,
IL-1β, IL-6 and IL-8.
89. Set 1 Active
Combined Data for Substance P Set 1 Latent
Set 1 Normal
600.00
Concentration in Trapezius over Time Set 2 Active
Set 2 Latent
Set 2 Normal
500.00
400.00
pg/L
300.00
200.00
100.00
0.00
0.00 5.00 10.00 15.00
Time (min)
90. Concentrations of Analytes in the Active
Group at Initial Needle Insertion
Analyte Trap GS *P value
pH 5.5 5.7 NS
Bradykinin 63.7 39.7 P<.001
NE 2.8 2.4 P<.001
Serotonin 6.5 6.0 P<.001
Substance P 140.9 52.9 P<.001
CGRP 129.9 46.7 P<.001
TNF-α 143.9 45.5 P<.001
IL-1β 97.1 44.8 P<.001
IL-6 102.5 39.6 P<.001
IL-8 48. 8 21.5 P<.001
*Trapezius > Gastrocnemius
98. Second Phase: What We’ve Learned
• An active MTrP has a unique biochemical milieu
of substances known to be associated with pain
states and inflammation
• The biochemical milieu of an active MTrP in the
upper trapezius differs quantitatively from a
remote, uninvolved site in the gastrocnemius
muscle.
99. Second Phase: What We’ve Learned
• Subjects with an active MTrP in the upper
trapezius have elevated levels of these analytes in
a remote, uninvolved muscle compared to latent
and normal subjects. This suggests that substances
associated with pain are not limited to local areas
of MTrPs or a single anatomical locus.
• In the trapezius, the concentration of specific
analytes dramatically changes in response to initial
needle insertion and also following a local twitch
response, particularly in active MTrPs
Shah JP, Danoff JV, Desai MJ, Parikh S, Nakamura LY, Phillips TM, Gerber LH.
Biochemicals assoicated with pain and inflammation are elevated in sites near to and
remote from active myofascial trigger points. Archives of Physical Medicine &
Rehabilitation 2008 Jan;89(1):16-23
103. “Pro-inflammatory cytokines
increase the sensitivity of all
peripheral neural structures and
their afferent cell bodies, causing
hyperalgesia and the
development of neuropathic pain
states”
Cytokines and Pain. Watkins
and Maier, eds. 2000
104. Hypernociceptive role of cytokines
and chemokines:
Targets for analgesic drug
development?
TNF-α, IL-1β, IL-6 and IL-8 were among the first
cytokines described as participating in the development of
inflammatory and neuropathic pain
Verri WA, Cunha TM, Parada CA et al
Pharmacology and Therapeutics 2006
105. Cytokine Cascade and Pain
Cg, LPS or Ag Ag
TNF-α IL-18 ↔ IL-12
IL-1β ↔IL-6 IL-8 ↔CINC-1 ET-1
Prostaglandins Sympathetic amines
Cox enzyme β-Blocker
Verri WA et. al
Pharmacology and
Therapeutics 2006
Nociceptor Sensitization
106. Moving Ahead: Microanalytic Systems for in-vivo
Measurement of the Biochemical Milieu of Muscle
Shah et al. J.
Appl. Physiol.
2005
99:1977-94
30-gauge needle
~0.5 ÎĽL sample
First Generation Microdialysis Needle
50-ÎĽm laser-drilled hole for embedding hydrogel
Second Generation Needle with Hydrogel
107. The Next Phase:
A Natural History Study
• Does the biochemical milieu at and around the MTrP
change with respect to the natural history of
myofascial pain in the upper trapezius?
• Does the biochemical milieu of the upper trapezius
correlate with changes in the severity of pain,
presence or absence of physical findings or degree of
local tenderness over time?
• What are the levels of anti-inflammatory substances
(e.g., IL-4, IL-10), neurotrophins (e.g., NGF, NT-3),
analgesic substances (e.g., β-endorphin) and
substances associated with muscle metabolism and
physiology (e.g., creatine kinase, aldolase, ACh
esterase, etc.)?
108. Treatment Trials
Assess the local biochemical milieu of MTrPs as an outcome
measure of efficacy in clinical treatment trials utilizing
pharmacologic and physical medicine approaches
110. Obstacles
• There are currently no imaging criteria for
the diagnosis of trigger points or for
assessing clinical outcome of treatments.
• It remains a clinical diagnosis based
exclusively on history and physical
examination.
111. Our Research Question
Can ultrasound imaging be used to develop objective
descriptions of the tissue and blood flow characteristics of
myofascial trigger points (MTrPs) and the immediately
adjacent structures?
In the long term, we want to understand the
pathophysiology of myofascial pain and develop
clinical outcome measures.
118. Sonoelastography Imaging
Objective
diagnostic test
Outcome
measure to
evaluate tissue
changes in
response to
treatment
Describe natural
history
Sikdar et al. Arch. Phys. Me
Rehabil., 2009 (in press)
119. Imaging blood flow near MTrPs in
the Upper Trapezius
A BFS=0
B BFS=1
C BFS=2
D BFS=2
120. Observations
• Ultrasound is feasible for imaging MTrPs
• MTrPs exhibit different echogenecity compared to
surrounding muscle.
• Vibration sonoelastography shows differences in relative
stiffness between trigger points and normal (uninvolved)
muscle. Sikdar et al. Assessment of Myofascial Trigger Points (MTrPs): A
New Application of Ultrasound Imaging and Vibration Sonoelastography. Conf
Proc. IEEE Eng Med Biol Soc. 2008
121. Observations
• Blood flow waveform characteristics can be used
to differentiate Active and Latent MTrPs
• Retrograde flow in diastole indicating a very high
resistance vascular bed and possible blood vessel
compression is associated with Active MTrPs
Sikdar S, Shah JP, Gebreab T, Yen R, Gilliams E, Danoff J, Gerber L.
Novel Applications of Ultrasound Technology to Visualize and
Characterize Myofascial Trigger Point and Surrounding Soft Tissue.
Archives of Physical Medicine and Rehabilitation. In press. 2009
122. Integrated
Neuromuscular
Theory
X
Inflamatory
Mediators, BK,
NE, SP,
Serotonin,
Cytokines
Courtesy Bryan O’Neill
