MYOFASCIAL PAIN SYNDROME ASNAWI BIN JOHARI 01BF-200904-00108
Myofascial Pain Syndrome (MPS)• Is a chronic muscular pain disorder in one muscle or groups of muscles presenting with vague complaints of poorly localized muscle pain and stiffness.• It is characterized by hyperirritable and tender spots within taut bands of skeletal muscle called “trigger points.”• The pathophysiology is unknown. Trigger points do not have any abnormal histological findings, and electromyograms of muscle affected by myofascial pain are normal. Lyn D.Weiss,Physical Medicine and Rehabilitation p.172-4
Additional impairments from the trigger points include:• decreased ROM when the muscle is being stretched,• decreased strength in the muscle,• increased pain with muscle stretching.The trigger points may be active (producing a classic pain pattern) or latent (asymptomatic unless palpated). Carolyn Kisner,Therapeutic Exercise p.318Myofascial pain affects up to 85% of the general population. Simons DG: Clinical and Etiological Update of Myofascial Pain from Trigger Points. Journal of Musculoskeletal Pain 1996, 4:93-122
ANATOMY OF FASCIA• Fascia is a thin membrane of loose or dense connective tissue that covers the structures of the body, protecting them and binding them into a structural unit.• Fascia separates the skin, layers of muscle, body compartments, and cavities. In addition, it forms sheaths for nerves and vessels that anchor them near the structures they regulate or nourish.• It also forms or thickens ligaments and joint capsules.
Fascia Layers -lies directly under the dermis of the skin. -stores fat and water and creates passageways for nerves and vessels.• Superficial fascia -Also called as the hypodermis. -made of loose connective tissue. -formed by a connective membrane that sheaths all muscles. -It aids in muscle movements, provides passageways for nerves and vessels, provides• Deep fascia muscle attachment sites, and cushions muscle layers. -This fascial layer is made of dense connective tissue. -separates the deep fascia from the membranes that line the thoracic and abdominal cavities of• Subserous fascia the body. -The loose connection between these layers allows for flexibility and movement of the internal organs. -dense connective tissue.
Throughout the body there is a subcutaneous layer ofloose connective tissue called the superficial fascia. Itcontains collagen fibers as well as variable amounts offat. Superficial fascia increases skin mobility, acts as athermal insulator, and stores energy for metabolic use.The dense connective tissue envelope that invests andseparates individual muscles of the limbs and trunk isdeep fascia. It is also composed primarily of collagenfibers. JAOA • Vol 103 • No 12 • December 2003 • 5 8 3
Moving on to a more functional description of the fascia, Chila eloquently and succinctly defined its role in structural support, motion, and maintenance of balance:• Fascia of the human body can be described as a sheet of fibrous tissue that envelops the body beneath the skin;• it also encloses muscles and groups of muscles, separating their several layers or groups....• In addition to extensive attachment for muscles, the fascia of the human body is provided with sensory nerve endings and is thought to be elastic as well as contractile.• Fascia supports and stabilizes, helping to maintain balance.• It assists in the production and control of motion and the interrelation of motion of related parts.• Many of the body’s fascial specializations have postural functions in which stress bands can be demonstrated.
Langers lines:These are normal, permanentskin creases that reflect the fiberorientation of the superficialfascia and the muscles that liebelow.
Myofascial Unit (mf)• A myofascial unit (mt) is composed of a group of motor units that move a body segment in a specific direction, together with the fascia that connects these forces or vectors.• The myofascial unit (mt) is, after the motor unit, the structural basis of the locomotor system.Fascial manipulation for musculoskeletal pain, Luigi Stecco,2004.
The structure of the myofascial unitMovement at each joint of the body is coordinated by six unidirectional mf units . The following components are found in each mf unit:• monoarticular and biarticular muscle fibres that are partially free to slide in their fascial sheaths;• deep muscle fibres that transfer their tension to the superficial fascial layers via the endomysium, the perimysium and the epimysium;• some muscle fibres of the agonist mf unit that are attached to the fascia of the antagonist mf unit.
History• Patients can be of any age or either sex. They generally describe poorly localized pain in muscles and joints with sensory disturbances that are usually worse with exercise and stretching.• The onset can be acute (after a specific event) or chronic from overuse or poor posture.
Physical examination• Posture.• The range of motion of all affected limbs and spine.• Assess for pain with movement or joint subluxations.• Muscle power.• Soft tissue palpation (including superficial and deep tissue texture with about 3 lbs of force) should be performed, observing for taut bands, twitch response, jump sign, or reproducibility of the patient’s symptoms.• Patient’s typical pattern of referred pain.• A local twitch response is elicited by snapping the trigger point manually.• The involved region may exhibit decreased range of motion and some pain-related local muscle weakness.
Investigations• No specific imaging or lab work is diagnostic. They can be used to rule out other causes of pain.
Spray-and-stretch techniqueThis involves passive stretching of the affected muscle.• Position the patient for maximum decrease in muscle tension.• Clearly identify the trigger points and mark them.• Apply vapocoolant (ethyl chloride) over the entire length of the affected muscle.• Passively stretch the muscle by applying gentle pressure.• Repeat “spray and stretch” until full range of motion is attained.• Use caution with vapocoolant—do not spray for >6–10 seconds with each stretch.
Physical therapy and modalities• TENS• Ultrasound• Massage• Myofascial release technique Bron C, Wensing M, Franssen JL, Oostendorp RA: Treatment of myofascial trigger points in common shoulder disorders by physical therapy: a randomized controlled trial [ISRCTN75722066]. BMC Musculoskelet Disord 2007, 8:107.
Other treatments• Aerobic exercises• Acupuncture 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, 25:130-136.• Medication• Short-term use of muscle relaxants and NSAIDs (can be used in combination)• Analgesics Wheeler AH: Myofascial pain disorders: theory to therapy. Drugs 2004, 64:45-62.
Invasive techniqueTrigger point injection• Local anesthetic:• <1 mL of 1% lidocaine is used most often.• Procaine is preferred because it is selective for small unmyelinated fibers that control pain perception.• Steroids: use if there is an adjacent area of infl ammation, e.g., frozen shoulder• Botulinum toxin: emerging therapy (4 concluded that it was not effective for reducing pain arising from trigger points) Ho KY, Tan KH: Botulinum toxin A for myofascial trigger point injection: a qualitative systematic review. Eur J Pain 2007, 11:519-527.• Dry needling: multiple advances of a needle into the trigger point Tough EA, White AR, Cummings TM, Richards SH, Campbell JL: Acupuncture and dry needling in the management of myofascial trigger point pain: a systematic review and meta-analysis of randomised controlled trials. Eur J Pain 2009, 13:3-10.
Complications of Trigger Point injections• Pneumothorax• Hematoma• Bleeding• Transient nerve block• Soft tissue infection• Postinjection soreness• Allergic reaction
“Neither standard diagnostic procedures to identify myofascial pain nor discriminating variables to distinguish the different entities of myofascial pain syndrome are available. Therefore we conclude that multiple diagnostic approaches may lead to therapeutic confusion.”Discrepancy between prevalence and perceived effectiveness of treatment methods in myofascial pain syndrome: Results of a cross-sectional, nationwide surveyFleckenstein et al. BMC Musculoskeletal Disorders 2010, 11:32 http://www.biomedcentral.com/1471-2474/11/32