Myofascial Pain SyndromeDiagnosis and Treatment

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Myofascial Pain Syndrome

• A clinical syndrome caused by myofascial trigger points (MTrPs)

Definition of Myofascial Trigger Point (MTrP)

• A highly localized and hyperirritable spot in a palpable taut band of skeletal muscle fibers.

Myofascial Pain SyndromeReferred Pain

Trigger Point

局部抽�反應Local Twitch Response

(Travell & Simons, 1983)

Latent VS Active MTrPs

Characteristics Latent Active

Taut band + ++ +++ ++++LTR + ++ +++ ++++Limited ROM +/- + ++ +++Tenderness + ++ +++ ++++Referred tender +/- + ++ +++Pain (spontaneous) - + ++ +++Referred pain - -/+ + ++Weakness - - -/+ +ANS disorder - - - -/+

Taut band

Taut band

MTrP region

Endplate Zone

LTR locus EPN locus MTrP Locus [Hong & Simons: APMR 1998]

Basic Units of Myofascial Trigger Point

MTrP Circuit #3

MtrP #3

MTrP Circuit #2

MtrP #2

MTrP Circuit #1

MtrP #1

PainReP

LTR

Stimulic

ANS

ANS

ANS

MTrP Circuit

1. (Pain)2. (ReP)3. (LTR) 4. (ANS)

Etiology of MTrPs

• MTrPs are usually caused by or associated with• other neuromusculoskeletal disorders.

• and can be perpetuated or aggravated by some medical conditions (perpetuating factors).

BASIC PRINCIPLE of MYOFASCIAL PAIN THERAPY

1). To treat Underlying Etiological Lesion.

2). To provide Pain Control (inactivation of MTrPs).

3). To correct Perpetuating Factors.4). To perform Patient Education.5). To demonstrate Home Program.

Identification of Underlying Pathological Lesion:

Active MTrP

Latent MTrP

Central sensitization 2nd to:Soft tissue lesions, Neurogenic lesionsEndocrine disorders (Fibromyalgia), Other factors

Inactivation of MTrPs General Consideration - 1:

Conservative VS Aggressive Treatment:

• Conservative Treatment: physical medicine–Any MTrPs with pain or discomfort.

• MTrP Injection:– Poor response to conservative therapy –Deeply seated MTrPs, – Chronic recurrent MTrPs, –Very active MTrPs, – etc.

Commonly Applied Techniques to inactivate (immediately release) MTrPs:

• 1. Physical Therapy• 2. Chiropractic Therapy• 3. Acupuncture• 4. Myofascial Trigger Point Injection• 5. Others.

Dry Needling and Acupuncture • 1). Basic Principle:

a. Spinal Cord Mechanism -Effect of dry needling: LTRs = [Hong: 1994]

b. Endogenous opioid system: Neurotransmitters: 5HT, etc.

c. Others. Acupuncture point Vs Trigger Point.[Melzack: Arch Phys Med Rehabil 62:114-7, 1981]

Dry Needling & Acupuncture 2). Clinical Application: •a. Dry Needling – Local twitch responses.

[Lewit: Pain 6:83-90, 1979] [Gunn et al: Spine 5:279-91, 1980][Hong: Am J Phys Med Rehabil 73:256-63, 1994][Chu J: Electromyogr Clin Neurophysiol 37:259-272, 1997]

• b. Traditional acupuncture - .

BASIC PRINCIPLES OF MTrP INJECTIONA. Before considering MTrP injection:• 1. Previous conservative treatment.• 2. Previous treatment for etiological

lesions.• 3. Pain recognition.• 4. Key Trigger Points..

Identification of Etiological Lesions based on Clinical Presentation of Active MTrP

Key MTrPs Satellite MTrPsSplenius capitis Temporalis; Semispinalis;

Sternocleidomastoid Temporalis; Masseter; Digastrics;

Upper trapezius Temporalis; Masseter; Splenius capitis; Semispinalis; Levator scapulae; Rhomboid;

Scaleni Deltoid; Extensor carpi radialis; Extensor digitorum communis; Extensor carpi ulnaris;

Supraspinatus Deltoid; Extensor carpi radialis;

Infraspinatus Biceps;

Key MTrPs Satellite MTrPsPectoralis minor Flexor carpi radialis; Flexor carpi ulnaris;

First dorsal Interosseous;Latissimus dorsi Triceps; Flexor carpi ulnaris;

Serratus post. Inf. Triceps; Latissimus dorsi; Extensor digitorum communis; Extensor carpi ulnaris; Flexor carpi ulnaris;

L5-S1 multifidi. Gluteal muscles; Hamstrings; Tibialis anterior; Peroneus longus; Gastrosoleus;

Quadratus lumborum Gluteal muscles;

Piriformis Hamstrings;

Hamstrings Peroneus longus; Gastrosoleus;

BASIC PRINCIPLES OF MTrP INJECTIONB. During MTrP injection:

1. Localization of sharp tenderness & taut band.2. Location of the needle tip.3. Local twitch response (LTR). 4. Straight needle insertion

- "Fast-in and fast out".

BASIC PRINCIPLES OF MTrP INJECTIONC. After MTrP injection:

1. Hemostasis.2. Continuing home program.3. Continuing physical therapy as indicated.

INDICATION FOR MTrP INJECTION:A. Pain Relief (Pain Control):1. For long-term pain control:1). Primary myofascial pain syndrome (traumatic,

postural) – if no involvement of tissues other than muscle / fasciae.

2). Secondary myofascial pain syndrome - after appropriate treatment of etiological lesions.3). Other special cases.

INDICATION FOR MTrP INJECTION:A. Pain Relief (Pain Control):2. For short-term pain control: 1). A substitute for narcotic analgesics. 2). Some fibromyalgia patients.3). Other special consideration.

INDICATION FOR MTrP INJECTION:B. Improving Functional Status:

Inactivation of MTrP (reduced pain)& Relaxation of the taut bands (increased

ROM)→ to increase mobility & function of

the involved muscles

INDICATION FOR MTrP INJECTION:C. Facilitating Tissue Repair: Reduced muscle tightness and spasm→to improve the local circulation→to interrupt the vicious cycle phenomena of

an MTrP, (for MTrP itself). →to facilitate the resolution of inflammation,

(for the etiological factor of a MTrP)

CONTRTRAINDICATION FOR MTrP INJECTION 1. Acute infection in the MTrP region or vicinity.2. Bleeding tendency, or anticoagulant therapy.3. Allergies to the specific anesthetics being injected.4. Acute trauma. 5. Malignancy.6. Others.

Materials Used for MTrP Injections: (1)

0.5% Procaine or Lidocaine, 0.5 - 1 ml for each site.Minimal systemic toxicity, Least myotoxicity, Absence of local irritation, Easy sterilization, Reasonable duration of action, Low cost.

Materials Used for MTrP Injections: (2)

Epinephrine in local anesthetic solution - not recommended.Increases hazard of accidental intravenous injection; myotoxicity.

Steroid in local anesthetic solution not recommended.

Myotoxicity-muscle fiber damage; MTrP is no an inflammatory lesion.

Materials Used for MTrP Injections: (3)

Dry needling- effective to inactivate a MTrP. Post-injection soreness.

Large amount of local anesthetic– not provide further benefit. .

Needle for MTrP Injection

Large size needle: to "feel" tissue texture through the needle; to avoid "fracture" of needle during injection.

Small size needle:to cause less pain; to avoid excessive bleeding.

Recommended Needle for MTrP Injection

#25, 11/2 inchfor large, thick, or deep muscles; for vigorous LTRs, for nervous patient;

# 27, 11/4 inch for small or thin muscles; for cooperative patient; skilful technique required.

Recommended Needle for MTrP Injection

• An 11/2 - inch needle is usually long enough for most of thick or deep muscles if the muscle is compressed with fingers during injection.

Syringe for MTrP Injection

• 5-cc or 10-cc syringe• It can be held most comfortably.

Syringe for MTrP Injection 5-cc or 10-cc syringe• It can be held most comfortably.

Positioning for MTrP Injection• Patient:

Recumbent position,or Sitting comfortably in an armchair.

• Physician:Comfortable sitting position, or comfortable

standing, well-supported, position.Both hands well-supported.

Procedure of Myofascial Trigger Point Injection•1. Identification of the MTrP.•2. Skin preparation

- sterilization (& anesthesia). •3. Skin penetration

- to subcutaneous tissue layer.

Procedure of Myofascial Trigger Point Injection• 4. Palpation of MTrP:

Firm compression of MTrP (or taut band near MTrP) with index or middle finger of the other hand to locate taut band & minute tender sites in that MTrP region.

• 5. Aim the needle to the minute tender site(s)

Procedure of Myofascial Trigger Point Injection• 6. Multiple insertions with

fast-in and fast-out technique to search for MTrP loci:- Rapid insertion of needle into a LTR locus, - Injection of MTrP loci if LTR is elicited, with a drop of 0.5% Procaine (or Lidocaine).

- Rapid withdrawal of needle back to subcutaneous layer,

- Elimination of all LTR loci as possible.••

Procedure of Myofascial Trigger Point Injection

• 7. Hemostasis - Epidermal & Intramuscular.- Firm compression to the site of injection.- Compression dressing over the site of injection.- Cold pack (with stretch) immediately after

injection, for 3-5 minutes, only if arterial penetration is noticed.

• 8. Hot pack for several minutes after injection.

Frequency and Total Number of Repeated Injections - for Fibromyalgia patients.***No fixed rule - case by case***

Frequency Total Duration

Acute lesions

Every 5-10 days for 1-3 weeks

Chronic lesions

Every 1 week,Then every 2 weeks,Then Every 3-4 weeks,Then Every 1 month,Then Every 2 months,and so forth.

for few weeks,for few weeks,for few months,for few months,for 6-12 months,etc.

SIDE EFFECTS of MTrP INJECTION– and PREVENTION(A). Injury to Muscle Fibers →scar tissues (Fibrosis)?• Scarring usually can be avoided by: • 1. Reducing bleeding from injections. • 2. Avoiding direct scratching by the needle

(using fast-in and fast-out technique).• 3. Avoiding injection into an area

with active inflammatory process.

SIDE EFFECTS of MTrP INJECTION– and PREVENTION(B). Injury to Nerve Fibers

O.K. to penetrate the nerve (straight movement of the needle),but not to cut (side movement of the needle).

SIDE EFFECTS of MTrP INJECTION– and PREVENTION

• (C). Injury to Blood Vessels: Ecchymosed / Hematoma.

• (D). Infection – very rare.• (E). Syncope or Anaphylactic Reaction

– probably due to intravenous injection of xylocaine.

• (F). Internal Organ Injury. All the complications are preventable; their prevention depends on the physician's knowledge of anatomy and the care exercised.

SIDE EFFECTS of MTrP INJECTION– and PREVENTIONInternal Organ Injury form MTrP Injection• Lung: Pneumothorax

Serratus (ant, post sup, post inf) muscles, Intercostal muscles, Subscapularis, Pectoralis minor, Upper quadratus lumborum, Thoracic paraspinal, Iliocostalis muscles.

SIDE EFFECTS of MTrP INJECTION– and PREVENTIONInternal Organ Injury form MTrP Injection• Peritoneums: Pneumoperitonium

Rectus abdominis muscles, Oblique muscles, Quadratus lumborum.

• Intestine or stomach: Abdominal muscles.

• Liver: Intercostal muscles, Serratus posterior inferior.

• Kidney: Quadratus lumborum.

CAUSES OF FAILURE IN IMMEDIATE PAIN RELIEF:A. Technical factors:

• 1). No precise location of loci in an MTrP region - no LTR elicited during injection.

• 2). Incomplete inactivation of all sensitive loci in an MTrP region.

• 3). Excessive damage to muscle fibers, nerve fibers or vessels.

CAUSES OF FAILURE IN IMMEDIATE PAIN RELIEF:B. Diagnostic factors:• 1). Inappropriate determination of a primary

MTrP (pain recognition)• 2). Inappropriate determination of a "Key MTrP".• 3). Unreliable information from patients (pain

location, intensity, etc.).• 4). Superimposed fibromyalgia syndrome.• 5). Neurogenic pain, central pain or psychogenic

pain.

CAUSES OF EARLY RECURRENCE:A. Technical Factors • 1). Incomplete inactivation of all sensitive

loci in an MTrP region.• 2). Excessive damage to muscle fibers,

nerve fibers or vessels.• 3). Inadequate hemostasis after injection.

CAUSES OF EARLY RECURRENCE:B. Diagnostic Factors• 1). Inappropriate diagnosis and/or treatment of the

etiological lesions.• 2). Inappropriate evaluation and control of

perpetuating factor.• 3). Long-standing or chronic myofascial pain

syndrome.• 4). Superimposed fibromyalgia syndrome.• 5). Neuralgic pain, central pain or psychogenic

pain.

CAUSES OF EARLY RECURRENCE:C. Aftercare Factors • 1). Inappropriate medical care:

(excessive, inadequate, or inaccurate).Medication, physical therapy, Alternative medicine, etc.

• 2). Inadequate or inappropriate home program.

CAUSES OF EARLY RECURRENCE:C. Aftercare Factors

• 3). Inappropriate physical and/or mental activity:(excessive, inadequate, or inaccurate).Posture, Daily living activity, Recreation, Exercise, Working status (body mechanics, working environment, etc),

1. Location of AcPs and MTrPs

• MTrPs are always identified in the endplate zone.• Some AcPs are identified in the endplate zone.•• A high degree (71%) of correspondence between

MTrPs and AcPs. [Melzack 1977]

2. Clinical Characteristics of AcPs and MTrPs

(1). Tenderness– All MTrPs are tender.– Some AcPs (Ah-Shi points) are tender.

Ah-Shi = 阿是• = Oh! Yes. (That is the spot.)

2. Clinical Characteristics of AcPs and MTrPs

(1). Tenderness• Ah-Shi points may include

Myofascial trigger points (MTrPs), Subcutaneous trigger points (STrPs), Tendon trigger points (TTrPs),Ligament trigger points (LTrPs), etc.

Sensitized DysfunctionalNerve Endings Endplates

LTR Locus EPN Locus

MTrP Locus

Tender Points in Trigger Points inFibromyalgia Syndrome Myofascial Pain syndrome

Other TrPs FTrP TTrP STrP MTrP

TrP = trigger pointM = myofascialS = subcutaneousT = tendonF = facet

2. Clinical Characteristics of AcPs and MTrPs

(2). Referred Pain (ReP)• High-pressure stimulation to MTrP

- ReP can be elicited in most of active MTrPs& some of latent MTrPs.

• Needling to AcP- ReP can be elicited in some AcPs.

Referred pain patterns of MTrPs are similar to Channel (Meridian) connections of AcPs. (Spinal cord mechanism –MTrP Circuit) [Hong 2000]

Referred Pain

TriggerPoint

MTrP Circuit #3

MtrP #3

MTrP Circuit #2

MtrP #2

MTrP Circuit #1

MtrP #1

PainReP

LTR

Stimulic

ANS

ANS

ANS

2. Clinical Characteristics of AcPs and MTrPs

(3). Local Twitch Response (LTR)- High-pressure stimulation to MTrP

- LTRs can be elicited in all active MTrPs & some of latent MTrPs.- Needling to AcP

- Teh-Qui effects 得氣 (similar to LTRs) can be elicited insome AcPs.

The best therapeutic effect after MTrP injection or acupuncture is related to the occurrence of LTRs or Teh-Qui effect.[Chu 1995, 1997; Gunn 1980; Hong 1993, 1994, 1996, 2000; Hong & Simons 1998]

3. Morphological Characteristics of AcPs and MTrPs

• MTrP: – Multiple loci. = Nociceptors + Dysfunctional endplates [Hong 1993, 1994, 1996,

1999; Hong & Simons 1998].

– Contraction knots in electromicroscopy [Simons 1999]

or Sonography [Gerwin et al 2002].

• AcP: ?– Nociceptors? – Other sensory receptors? – Related to the autonomic nervous system or others?

• Morphologically, it is difficult to differentiate a normal sensory receptors and an abnormal (sensitized) sensory receptors.

4. Pathophysiological Characteristics of AcPs and MTrPs

• MTrP:– Spinal cord mechanism (ReP and LTR)– Autonomic connection (RSD).

• AcP:– Spinal cord mechanism? – Autonomic mechanism?– Endocrine system?

MTrP Circuit #3

MtrP #3

MTrP Circuit #2

MtrP #2

MTrP Circuit #1

MtrP #1

PainReP

LTR

Stimulic

ANS

ANS

ANS

5. Therapeutic Effectivenessof Acupuncture and MTrP injection

• MTrP Injection:– MTrP injection for pain control

- spinal cord mechanism (including autonomic influence in RSD)

• Acupuncture:– Acupuncture for pain control

- spinal cord mechanism– Acupuncture for other therapeutic purposes

- spinal cord mechanism – connection with autonomic system? Autonomic influence? (to treat hypertension etc)Endocrine influence? (to treat DM etc)