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Muscular Dystrophy


Duchenne muscular dystrophy is the most severe form of dystrophinopathy. It occurs mostly in young boys and is the most common form of MD that affects children. – PowerPoint PPT presentation

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Title: Muscular Dystrophy

  • Amjad Moiffak Moreden, M.D.
  • Department of Orthopaedic Surgery
  • The General Assembly of Damascus Hospital
  • Ministry of Health
  • Damascus, Syria
  • Jun. 26, 2007

  • Muscular dystrophy (MD) is a group of rare
    inherited muscle diseases in which muscle fibers
    are unusually susceptible to damage. Muscles,
    primarily voluntary muscles, become progressively
    weaker. In the late stages of muscular dystrophy,
    fat and connective tissue often replace muscle
    fibers. In some types of muscular dystrophy,
    heart muscles, other involuntary muscles and
    other organs are affected.
  • The most common types of muscular dystrophy
    appear to be due to a genetic deficiency of the
    muscle protein dystrophin.
  • There's no cure for muscular dystrophy, but
    medications and therapy can slow the course of
    the disease.

  • muscular dystrophy (MD) describes a group
    of primary genetic disorders of muscle that often
    have a distinctive and recognizable clinical
    phenotype, accompanied by characteristic, but
    frequently not pathognemonic, pathological

Muscular Dystrophy Types and Genes
  • Duchenne MD DMD Dystrophinopathy
  • Becker MD BMD Dystrophinopathy
  • Emery-Dreifuss MD EDMD
  • Dominant Emery-Dreifuss MD AD-EDMD
  • Limb-girdle MD type 1A LGMD1A
  • Limb-girdle MD type 1B LGMD1B
  • Limb-girdle MD type 1C LGMD1C
  • Limb-hirdle MD type 1D LGMD1D
  • Limb-girdle MD type 1E LGMD1E
  • Limb-girdle MD type 2A LGMD2A Calpainopathy
  • Limb-girdle MD type 2B LGMD2B Dysferlinopathy
  • Miyoshi myopathy MM Dysferlinopathy
  • Miyoshi-type MD MMD
  • a-Sarcoglycanopathy SGCA LGMD2D, SCARMD2
  • ß-Sarcoglycanopathy SGCB LGMD2E
  • ?-Sarcoglycanopathy SGCC LGMD2C, SCARMD1
  • d-Sarcoglycanopathy SGCD LGMD2F
  • Limb-girdle MD type 2G LGMD2G
  • Limb-girdle MD type 2H LGMD2H

M.D. Types
  • There are nine major types of MD affecting
    people of all ages, from infancy to middle age or
    later. The two most common types of MD affect
  • Duchenne muscular dystrophy (DMD)
  • Becker muscular dystrophy (BMD)

Signs and symptoms
  • They vary according to the type of muscular
    dystrophy. In general, they may include
  • Muscle weakness
  • Apparent lack of coordination
  • Progressive crippling, resulting in contractures
    of the muscles around your joints and loss of
  • Many specific signs and symptoms vary from among
    the different forms of MD. Each type is different
    in the age of onset, what parts of the body the
    symptoms primarily affect and how rapidly the
    disease progresses.

Signs and symptomsCont..
  • DystrophinopathiesThese types of muscular
    dystrophies are due to a genetic deficiency of
    the protein dystrophin.

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Signs and symptomsCont..
  • Duchenne muscular dystrophy is the most
    severe form of dystrophinopathy. It occurs mostly
    in young boys and is the most common form of MD
    that affects children. Signs and symptoms of
    Duchenne MD may include
  • Frequent falls
  • Large calf muscles
  • Difficulty getting up from a lying or sitting
  • Weakness in lower leg muscles, resulting in
    difficulty running and jumping
  • Waddling gait
  • Mild mental retardation, in some cases

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Gower's maneuver
Signs and symptomsCont..
  • Duchenne usually appear between the ages of 2 and
    5. It first affects the muscles of the pelvis,
    upper arms and upper legs. By late childhood,
    most children with this form of muscular
    dystrophy are unable to walk. Most die by their
    late teens or early 20s, often from pneumonia,
    respiratory muscle weakness or cardiac
    complications. Some people with Duchenne MD may
    exhibit curvature of their spine (scoliosis).
  • Becker's muscular dystrophy is a milder form of
    dystrophinopathy. It generally affects older boys
    and young men, and progresses more slowly,
    usually over several decades. Signs and symptoms
    of Becker's MD are similar to those of Duchenne.
    The onset of the signs and symptoms is generally
    later, and those affected by Becker's MD usually
    are able to walk until at least age 15, and often
    well into adulthood.

Signs and symptomsCont..
  • Myotonic dystrophy Also known as
    Steinert's disease, this form of muscular
    dystrophy produces stiffness of muscles and an
    inability to relax muscles at will (myotonia), as
    well as the muscle weakness of the other forms of
    muscular dystrophy.
  • Although this form of MD can affect
    children, it often doesn't affect people until
    adulthood. It can vary greatly in its severity.
    Muscles may feel stiff after using them.
    Progression of this form of MD is slow.

Signs and symptomsCont..
  • Besides myotonia, signs and symptoms of
    adult-onset myotonic dystrophy may include
  • Weakening of voluntary muscles that control your
    arms and legs, usually beginning with the limb
    muscles farthest from the torso the muscles of
    the feet, hands, lower legs and forearms.
  • Weakening of head, neck and face muscles, which
    may result in the face having a hollow, drooped
  • Weakening of muscles involved in breathing and
    swallowing. Weaker breathing muscles may result
    in less oxygen intake and fatigue. Weaker
    swallowing muscles increase the risk of choking.
  • Fainting or dizziness, which may indicate that
    the disease is interfering with the conduction of
    electrical signals that keep the heart rate
  • Weakening of muscles of hollow internal organs
    such as those in the digestive tract and the
    uterus. Depending on which part of the digestive
    tract is affected, you may experience problems
    with swallowing as well as constipation and
    diarrhea. Weakness of the uterine walls may cause
    problems during childbirth.
  • Difficulty sleeping well at night and daytime
    sleepiness, and inability to concentrate because
    of the effect of the disease on the brain.
  • Frontal balding in men.
  • Clouding of the lenses of the eyes (cataracts).
  • Mild diabetes.

Signs and symptomsCont..
  • Rarely, infants have this form of muscular
    dystrophy, in which case it's called congenital
    myotonic dystrophy. The infant form is more
    severe, although infants with myotonic dystrophy
    don't experience myotonia. Signs in infants may
  • Severe muscle weakness
  • Difficulty sucking and swallowing
  • Difficulty breathing
  • Cognitive impairment

Signs and symptomsCont..
  • Facioscapulohumeral DystrophyAlso
    known as Landouzy-Dejerine disease, this form
    involves progressive muscle weakness, usually in
    this order
  • Face
  • Shoulders
  • Abdomen
  • Feet
  • Upper arms
  • Pelvic area
  • Lower arms
  • When someone with facioscapulohumeral MD
    raises his or her arms, the shoulder blades may
    stick out like wings. Progression of this form is
    slow, with some spurts of rapidly increasing
    weakness. Onset usually occurs during the teen to
    early adult years.

Signs and symptomsCont..
  • The other major types of muscular dystrophy
    are rare. They include
  • Limb-girdle muscular dystrophy
  • Congenital muscular dystrophy
  • Oculopharyngeal muscular dystrophy
  • Distal muscular dystrophy
  • Emery-Dreifuss muscular dystrophy

1- X-linked recessive inheritance pattern with carrier mother
2- Autosomal dominant inheritance pattern
X-linked recessive inheritance pattern with
carrier mother
  • Duchenne and Becker's muscular dystrophies are
    passed from mother to son through one of the
    mother's genes in a pattern called X-linked
    recessive inheritance. Boys inherit an X
    chromosome from their mothers and a Y chromosome
    from their fathers. The X-Y combination makes
    them male. Girls inherit two X chromosomes, one
    from their mothers and one from their fathers.
    The X-X combination determines that they are

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Autosomal dominant inheritance pattern
  • Patterns differ for other types of MDMyotonic
    dystrophy is passed along in a pattern called
    autosomal dominant inheritance. If either parent
    carries the defective gene for myotonic
    dystrophy, there's a 50 percent chance the
    disorder will be passed along to a child.
  • Some of the less common types of muscular
    dystrophy are passed along in the same
    inheritance pattern that marks Duchenne and
    Becker's muscular dystrophies. Other types of
    muscular dystrophy can be passed on from
    generation to generation and affect males and
    females equally. Still others require a defective
    gene from both parents.

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Screening and diagnosis
  • Blood tests. Damaged muscles release enzymes such
    as creatine kinase (CK) into the blood. High
    blood levels of CK suggest a muscle disease such
    as muscular dystrophy.
  • Electromyography. A thin-needle electrode is
    inserted through your skin into the muscle to be
    tested. Electrical activity is measured as you
    relax and as you gently tighten the muscle.
    Changes in the pattern of electrical activity can
    confirm a muscle disease. The distribution of the
    disease can be determined by testing different
  • Ultrasonography. High-frequency sound waves are
    used to produce precise images of tissues and
    structures within your body. An ultrasound is a
    noninvasive way of detecting certain muscle
    abnormalities, even in the early stages of the
  • Muscle biopsy. A small piece of muscle is taken
    for laboratory analysis. The analysis
    distinguishes muscular dystrophies from other
    muscle diseases. Special tests can identify
    dystrophin and other markers associated with
    specific forms of muscular dystrophy.
  • Genetic testing. Blood samples are examined for
    mutations in the gene that produces dystrophin.
    Standard tests examine just the portions of the
    dystrophin gene responsible for most cases of
    Duchenne and Becker's muscular dystrophies. These
    tests identify deletions or duplications on the
    dystrophin gene in about two-thirds of people
    with Duchenne and Becker's MDs. The genetic
    defects responsible for Duchenne and Becker's
    muscular dystrophies are harder to identify in
    other cases of those affected, but new tests that
    examine the entire dystrophin gene are making it
    possible to pinpoint tiny, less common mutations.

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  • There's currently no cure for any form of
    muscular dystrophy. Research into gene therapy
    may eventually provide treatment to stop the
    progression of some types of muscular dystrophy.
    Current treatment is designed to help prevent or
    reduce deformities in the joints and the spine
    and to allow people with MD to remain mobile as
    long as possible. Treatments may include various
    types of physical therapy, medications, assistive
    devices and surgery.

Treatment Cont..
  • Physical therapyAs muscular dystrophy
    progresses and muscles weaken, fixations
    (contractures) can develop in joints. Tendons can
    shorten, restricting the flexibility and mobility
    of joints. Contractures are uncomfortable and may
    affect the joints of your hands, feet, elbows,
    knees and hips.
  • One goal of physical therapy is to provide
    regular range-of-motion exercises to keep your
    joints as flexible as possible, delaying the
    progression of contractures, and reducing or
    delaying curvature of your spine. Using hot baths
    (hydrotherapy) also can help maintain range of
    motion in joints.

Treatment Cont..
  • Medications
  • For myotonic dystrophy. The medications
    mexiletine (Mexitil), phenytoin (Dilantin,
    Phenytek), carbamazepine (Tegretol, Carbatrol),
    quinine and procainamide (Procanbid, Pronestyl)
    may be used to treat the delayed muscle
    relaxation that occurs in myotonic dystrophy.
  • For Duchenne muscular dystrophy. The
    anti-inflammatory corticosteroid medication
    prednisone may help improve muscle strength and
    delay the progression of Duchenne MD.

Treatment Cont..
  • Assistive devicesBraces can both provide
    support for weakened muscles of your hands and
    lower legs and help keep muscles and tendons
    stretched and flexible, slowing the progression
    of contractures. Other devices such as canes,
    walkers and wheelchairs can help maintain
    mobility and independence. If respiratory muscles
    become weakened, using a ventilator may become

Treatment Cont..
  • Surgery ( three approaches ambulatory,
    rehabilitative, palliative )
  • Surgical release of contractures Cut through
    tendons to relieve contractures (tendon release
  • Spinal fusion for scoliosis Scoliosis in a
    wheelchair-dependent child with MD can become so
    severe it causes breathing problems and
    pneumonia. Having spine surgery before this
    happens can preserve breathing function, lessen
    back pain and improve sitting balance. All these
    factors improve the child's quality of life. The
    surgery is recommended when the spinal curve
    reaches a certain size (i.e., more than 20

Surgical Treatment
  • Percutaneous Release of Hip Flexion and Abduction
    Contractures and Tendo Calcaneus Contracture.
  • Open procedure technique

  • With the child supine on the operating table,
    prepare and drape both lower extremities from the
    iliac crests to the toes. First flex and then
    extend the hip to be released, holding the hip in
    adduction to place tension on the muscles to be
    released keep the opposite hip in maximal
    flexion to flatten the lumbar spine. Insert a no.
    15 knife blade percutaneously just medial and
    just distal to the anterosuperior iliac spine.
    Release the sartorius muscle first, then the
    tensor fasciae femoris muscle. Push the knife
    laterally and subcutaneouslywithout cutting the
    skinto release the tensor fasciae latae
    completely. Bring the knife to the original
    insertion point and push it deeper to release the
    rectus femoris completely. Take care to avoid the
    neurovascular structures of the anterior thigh.
    Next, approximately 3 to 4 cm proximal to the
    upper pole of the patella, percutaneously release
    the fascia lata laterally through a stab wound in
    its midportion. Push the knife almost to the
    femur to release the lateral intermuscular septum
    completely. Now perform a percutaneous release of
    the tendo calcaneus. Apply long leg casts with
    the feet in neutral position and with the heels
    well padded to prevent pressure ulcers.

Surgical Treatment Cont..
  • Transfer of Posterior Tibialis Tendon to Dorsum
    of Foot (posterior tibialis muscle overpull)

  • make a 3-cm incision starting medially at the
    neck of the talus and extending to the navicular.
    Open the sheath of the posterior tibial tendon
    from the distal extent of the flexor retinaculum
    to the navicular. Release the tendon from its
    bony insertions, preserving as much length as
    possible. Make a second incision 6 to 8 cm long
    vertically between the tendo calcaneus and the
    medial distal tibia. The tendo calcaneus can be
    lengthened through the same incision if
    necessary. Incise the posterior tibial tendon
    sheath and pull the distal portion of the tendon
    through the second operative wound. Make a third
    incision 6 cm long lateral to the anterior crest
    of the tibia and extend it to the superior
    extensor retinaculum. Incise the anterior
    compartment fascia and retract the tibialis
    anterior tendon laterally. Carefully incise the
    interosseous membrane on the lateral aspect of
    the tibia adjacent to its tibial insertion for a
    distance of 3 cm. Enlarge the opening by proximal
    and distal horizontal cuts, extending halfway
    across the interosseous membrane. Pass a curved
    clamp close to the tibia from the anterior
    compartment proximally into the second incision.
    Keep the curved clamp on the tibia to prevent
    injury to the peroneal vessels. After grasping
    the posterior tibialis tendon and pulling it into
    the third incision, inspect the tendon through
    the second incision to make sure that it has
    neither twisted on itself nor ensnared the flexor
    digitorum longus tendon. Make a fourth incision 3
    cm long on the dorsum of the foot in the region
    of the middle cuneiform. Incise the periosteum of
    the middle cuneiform and expose the central
    portion of the bone. Drill a hole 5 to 8 mm to
    insert the tendon through the middle of the
    cuneiform. Pass a Kelly clamp subcutaneously from
    the third incision to the fourth incision
    distally to create a subcutaneous tract for the
    posterior tibialis tendon. Pull the tendon
    through the subcutaneous tract with a tendon
    passer. Holding on to the sutures tied to the end
    of the posterior tibialis tendon, pass the tendon
    into the hole in the middle cuneiform and pass
    the sutures through the dorsum of the foot with
    the aid of straight needles. Release the
    tourniquet. Inspect, irrigate, and close the
    wounds. After the wounds have been closed tie the
    suture over a felt pad and button on the plantar
    aspect on the foot with the foot in a neutral
    position. Apply a long leg cast with the knee
    extended and the ankle in neutral position.

Surgical Treatment Cont..
  • Transfer of Posterior Tibialis Tendon to Dorsum
    of Base of Second Metatarsal (posterior tibialis
    muscle overpull)

  • With the patient supine and a tourniquet in
    place, make a 3-cm incision over the insertion of
    the posterior tibialis tendon on the navicular.
    Open the sheath of the posterior tibialis tendon
    from the anterior aspect of the medial malleolus
    to the navicular. Release the tendon from the
    bony insertions, preserving as much length as
    possible. Make a second incision in the
    posteromedial calf in the region of the
    myotendinous junction of the posterior tibialis
    tendon. A gastrocnemius recession can be
    performed through this incision if necessary, but
    excessive lengthening of the triceps surae
    complex should be avoided to prevent the
    development of a crouched gait postoperatively.
    Open the posterior tibial tendon sheath and pull
    the tendon through the sheath into the calf
    wound. At the myotendinous junction of the
    tibialis posterior, incise the tendon
    transversely halfway through its width. Extend
    this incision distally to within 0.5 cm of the
    cut insertion of the tibialis tendon. Secure the
    distal aspect of the tendon with a single suture
    to prevent the longitudinal cut from extending
    out to the end of the tendon. This procedure
    effectively doubles the length of the posterior
    tibialis tendon. Make a third incision, 6 cm long
    lateral to the anterior crest of the tibia,
    extending it to the superior extensor
    retinaculum. Perform an anterior compartment
    fasciotomy and retract the tibialis anterior
    tendon laterally. Incise the interosseous
    membrane of the lateral aspect of the tibia for a
    distance of 3 cm. Take a Kelly clamp and place it
    through the anterior compartment wound across the
    interosseous membrane and into the deep posterior
    compartment. Grasp the end of the lengthened
    posterior tibialis tendon and bring it through
    the interosseous membrane into the anterior
    compartment of the calf . Make another incision,
    2 to 3 cm long, over the base of the second
    metatarsal. Dissect down to the base of the
    second metatarsal and subperiosteally dissect
    around the base of the second metatarsal
    circumferentially. Take the elongated tibialis
    posterior tendon and tunnel it subcutaneously
    into the incision over the dorsum of the second
    metatarsal. Loop the tendon around the base of
    the second metatarsal as a sling and tie it to
    itself with the appropriate tension on the ankle
    to hold it into a neutral plantar flexion and
    dorsiflexion. Release the tourniquet and inspect
    the tibial vessels to make sure that they are not
    being kinked by the transferred tendon. Irrigate
    the wounds and close them in a standard fashion.

Surgical Treatment Cont..
Lengthening of Tendo Calcaneus(Equinus deformity)
Surgical Treatment Cont..
  • Scapulothoracic Fusion
  • (inability to functionally flex and abduct the
    shoulder )

  • Place the patient prone and manually position
    the scapula at 15 to 20 degrees of external
    rotation. Make an oblique 12-inch incision over
    the medial border of the scapula and transect the
    trapezius muscle. Release the rhomboids and
    levator scapula from their scapular insertions
    and elevate the supraspinatus, infraspinatus, and
    subscapularis muscles subperiosteally for 2 cm
    from the medial border of the scapula. Excise a
    2-cm strip of subscapularis muscles to allow
    approximation of the scapula to the thoracic
    wall. Usually ribs 3 through 7 are exposed
    subperiosteally for 2 cm. Pass double 16-gauge
    Luque wires subperiosteally under each rib. Use a
    sharp towel clip to make holes 1 cm from the
    medial ledge of the scapular points corresponding
    from the wired ribs. Use a burr to decorticate
    the posterior surface of the exposed rib margins
    in the corresponding points along the anterior
    surface of the scapula. Place strips of
    cancellous allograft taken from the posterior
    iliac crest between the denuded ribs and scapula.
    Tighten the wires sequentially

Treatment Cont..
  • Other treatmentsBecause respiratory
    infections may become a problem in later stages
    of muscular dystrophy, it's important to be
    vaccinated for pneumonia and to keep up-to-date
    with influenza shots.

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  • This lecture is one of a series of lectures were
    prepared and presented by residents in the
    department of orthopedics in Damascus hospital,
    under the supervision of Dr. Bashar Mirali.
  • This site is not responsible of any mistake may
    exist in this lecture.

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Dr. Muayad Kadhim