Muscular Dystrophies Neuromuscular Scoliosis Dr. Donald W. Kucharzyk Clinical Assistant Professor University of Chicago Children’s Hospital

Muscular DystrophiesNeuromuscular Scoliosis

Dr. Donald W. KucharzykClinical Assistant Professor

University of Chicago Children’s Hospital


“ “Definition”Definition”Group of genetically determined progressive diseases of skeletal musclesNot inflammatory in etiologyClassified as myopathies rather than as myositis


““Definition”Definition”Pathologic changes occur within the muscle fibers themselvesNo abnormality seen in the innervation of the musclesPeripheral nerves are normal


““Historical Aspects”Historical Aspects”Meryon in 1852 documented the first case of muscular dystrophyDuchenne in 1868 published a treatise on muscular dystrophyDuchenne described the entity as a muscle disease of childhood or adolescence


“ “Historical Aspects”Historical Aspects”Mostly seen in boysProgressive weakness of the musclesBegins in the lower limbs and spreads to the trunk and armsEnlargement of the weakened musclesHyperplasia of connective tissuesIncrease in fat cells in the affected muscles


“ “Historical Aspects”Historical Aspects”Gower in 1879 described the “Classic Clinical Sign” of the patient climbing up the legsLater described another form of muscular dystrophy that primarily affected the distal musculature


““Classification of Muscular Classification of Muscular Dystrophy”Dystrophy”X-Linked Recessive

Duchenne’s muscular dystrophy Becker’s muscular dystrophy

Autosomal Recessive Limb Girdle Congenital muscular dystrophy


““Classification of Muscular Classification of Muscular Dystrophy”Dystrophy”Autosomal Dominant

Facioscapulohumeral Scapuloperoneal Late-onset proximal Distal (adult) Distal (infant) Ocular


“ “Classification of Muscular Classification of Muscular Dystrophy”Dystrophy”Dystrophies with Myotonia

Myotonia congenita Dystrophia myotonia Paramyotonia congenita


““Etiology”Etiology”Gene responsible for Duchenne’s is located on the Xp21 region of the X chromosomeSpontaneous mutation occurs in one-third of the casesDystrophin is lacking in patients with muscular dystrophy (dystrophin necessary for cell membrane cytoskeleton)


““Pathology”Pathology”Pathologic changes seen within the muscles are similar in all forms of muscular dystrophyMost important histologic feature is loss of muscle fibers caused by segmental necrosisFiber necrosis with splitting, phagocytosis and fatty replacement are classic histopathologic findings


““Pathology”Pathology”Muscle biopsy is the most effective test to distinguish the various typesGeneral histological features include variation in fiber size, central location of muscle fibers, and degeneration of regional muscle fibersAnalysis for dystrophin in biopsy differentiates Duchenne’s from Limb-Girdle


“ “Biochemical Considerations”Biochemical Considerations”Creatine kinase is elevated although its not specificElevated to levels 20 to 200 times above normal levelsHighest in Duchenne’s than Becker’sAldolase is elevated and is classically highest early then declines as the disease progresses


““Biochemical Biochemical Considerations”Considerations”Dystrophin analysis reveals an absence or deficiency on the surface membrane of muscles cellsAssessment of dystrophin levels on muscle biopsy provides an index of prognosis for severity


“ “Electromyography”Electromyography”EMG can help differentiate myopathic and neuropathic processesEMG in muscular dystrophies shows low amplitude, short duration, polyphasic motor unit potentialsNCV are normal in patients with muscular dystrophies


““Duchenne’s Muscular Duchenne’s Muscular Dystrophy”Dystrophy”Most common form1 per 3500 malesMales manifest the disease, females carry the geneMust differentiate this process from Polymyositis early


““Duchenne’s Muscular Duchenne’s Muscular Dystrophy”Dystrophy”Clinically evident between three and six years of ageOnset of weakness insidiousAchieve developmental milestones at slightly older agesMild delay in walking seenGower’s sign may be seen as early as 15 months


““Duchenne’s Muscular Duchenne’s Muscular Dystrophy”Dystrophy”Presenting signs range from a waddling gait to a difficulty climbing stairsToe walking seen in the early stages of the diseaseMuscle weakness is symmetrical

Seen first in the proximal muscles with the hip extensors affected first


““Duchenne’s Muscular Duchenne’s Muscular Dystrophy”Dystrophy”Lower extremity involvement precedes upper involvement by 3 to 5 yearsAnkle equinus is the first signTrendelenburg gait seen due to proximal muscle weaknessGait reveals a slow cadence with altered stance


““Duchenne’s Muscular Dystrophy”Duchenne’s Muscular Dystrophy”Proximal shoulder girdle weakness produces the second clinical sign “Meryon’s Sign”As disease progresses, contractures occur throughout the lower extremitiesReflexes in the upper and knee lost early with sparing of the ankle until the terminal phaseEquinus and cavus foot deformities seen


““Duchenne’s Muscular Duchenne’s Muscular Dystrophy”Dystrophy”Scoliosis develops in late childhood or early adolescenceAppears as a mild curve but rapidly progressesLumbar kyphosis develops later especially with wheelchair useDystrophin levels analysis abnormal


““Duchenne’s Muscular Duchenne’s Muscular Dystrophy”Dystrophy”

Muscle BiopsyMuscle BiopsyProgressive changes with timeDegeneration and regenerationVariation fiber size, internal nucleiProliferation adipose and connective tissue


““Duchenne’s Muscular Dystrophy”Duchenne’s Muscular Dystrophy”

Cardinal Clinical SignsCardinal Clinical SignsWaddling gaitLordotic postureAbnormal run and inability to hopDifficulty rising from floorProximal muscle weakness leg>armsProminence of calves


““Becker’s Muscular Dystrophy”Becker’s Muscular Dystrophy”Similar to Duchenne’s but later onset and slower rate of deterioration of musclesAge at presentation usually after 7 yearsAmbulate into early adult yearsPseudohypertrophy of the calves seenDilated cardiomyopathy seen in high percentage of the patients


““Becker’s Muscular Dystrophy”Becker’s Muscular Dystrophy”

Muscle BiopsyMuscle BiopsyVariable dystrophic changesDegeneration and regenerationVariable loss of fibers and proliferation of adipose and connective tissueFoci of atrophic fibers resembling denervation


““Becker’s Muscular Dystrophy”Becker’s Muscular Dystrophy”

Cardinal Clinical SignsCardinal Clinical SignsMild functional disabilityProximal muscle weaknessProminence of calvesWaddling gaitLumbar lordosis


““Limb-Girdle Muscular Limb-Girdle Muscular Dystrophy”Dystrophy”Weakness of the proximal muscles of the limbsOnset usually in the second or third decade at average age 17.2 yearsMore benign than Duchenne’sAmbulatory ability persists for a longer period of time


““Limb-Girdle Muscular Limb-Girdle Muscular Dystrophy”Dystrophy”Most common type pelvic-femoral Affects iliopsoas, gluteus, and quadriceps initially with shoulder involvement laterScapulo-humeral type affects shoulder first followed by pelvic muscleDifficulty lifting arms, rising from floor and climbing stairs seen


““Limb-Girdle Muscular Dystrophy”Limb-Girdle Muscular Dystrophy”

Muscle BiopsyMuscle BiopsyDystrophic changes variableMarked variability in fibre size and splitting of fibresDegeneration and regenerationProliferation of adipose and connective tissue


““Limb-Girdle Muscular Limb-Girdle Muscular Dystrophy”Dystrophy”

Cardinal Clinical SignsCardinal Clinical SignsAbnormal gaitLordotic postureVariable muscle weaknessDeformities after loss of ambulationFunctional disability with hopping and rising from floor


““Congenital Muscular Congenital Muscular Dystrophy”Dystrophy”Evident at or shortly after birth as a floppy baby appearanceHypotonia and motor weakness of the limbs, trunk and facial muscles seenDifficulty in sucking and swallow seenStatic clinical course with mild progression of weakness seen


““Congenital Muscular Congenital Muscular Dystrophy”Dystrophy”Ambulation develops around two years of age and continues into adulthoodCommon orthopaedic conditions seen include DDH, equinus contractures, and clubfoot deformitiesScoliosis seen and is progressive and will require surgical stabilization


““Congenital Muscular Dystrophy”Congenital Muscular Dystrophy”

Muscle BiopsyMuscle BiopsyVariableMild myopathic and dystrophic changesExtensive dystrophic changes with marked replacement of muscle by adipose tissue and variable connective tissue


““Congenital Muscular Congenital Muscular Dystrophy”Dystrophy”

Cardinal Clinical SignsCardinal Clinical SignsGeneral hypotoniaWeaknessFixed deformities in relation to intrauterine postureVariable weakness or contractures in later presenting cases


““Spinal Muscular Atrophy”Spinal Muscular Atrophy”Group of genetically determined disorders of the anterior horn cells of the spinal cord Associated muscle weakness which is symmetrical affecting legs more than arms and proximal more than distalClassified into severe, intermediate and mild based upon ability to sit, stand and walk


““Spinal Muscular Atrophy”Spinal Muscular Atrophy”

SevereSevereWerdnig-Hoffmann DiseaseAge of onset: in utero or first few monthsHypotonia and weaknessSucking and swallowing difficultyRespiratory problems



Muscle BiopsyMuscle BiopsyLarge group atrophyIsolated or clusters of large fibres



Cardinal Clinical SignsCardinal Clinical SignsSevere limb and axial weaknessFrog postureMarked hypotoniaPoor head controlDiaphragmatic breathingCostal recession



Cardinal Clinical SignsCardinal Clinical SignsBell shaped chestInternal rotation of arms: jug handle postureNormal facial movementsAbsent tendon reflexesWeak cry



IntermediateIntermediateAge of onset: between 6 and 12 monthsWeakness of legsInability to stand or walkScoliosisExcessive joint laxityRespiratory problems



Muscle BiopsyMuscle BiopsyCharacteristic patterns of large group atrophy Variable clusters of enlarged fibresUniformly or predominantly type 1



Cardinal Clinical SignsCardinal Clinical SignsSymmetrical weakness of legs, predominantly proximalAble to sit but unable to stand or put full weight on legsFasciculations of tongue, facial muscles sparedTremors of handsAbsent reflexes



MildMildAge of onset from second year of life through childhood and adolescence into adulthoodDifficulty with activities such as running, climbing, steps, or jumpingLimitation in walking ability: quality and quantity



Muscle BiopsyMuscle BiopsyCharacteristic pattern of large group atrophyVariable groups of normal or enlarged fibresRetention of normal bundle architecture with fibre type groupingFocal small group atrophy



Cardinal Clinical SignsCardinal Clinical SignsAbnormal gait: waddling, flat-footed, wide basedDifficulty rising from floorProximal weakness legs>armsHand tremorTongue fasciculations


““Treatment”Treatment”Orthopaedic management focuses on maximizing the child’s function whenever possibleThe primary goal is to maintain functional ambulation as long as possibleTreatment involves PT, Orthotics, Steroid Therapy, and Surgical correction of contractures and deformities


““Physical Therapy”Physical Therapy”Prolongation of functional muscle strengthPrevention and correction of contracturesGait training and assistance in maintaining ambulationMaximum resistance exercises Prevent adaptive posturing due to contractures of musculature


““Steroid Therapy”Steroid Therapy”Prednisone therapy has shown to delay the loss of muscle strength for up to 3 yearsGriggs et al 1991: prednisone use increases strength as early as 10 days into treatmentResponse is dose related with higher muscle strength’s noted at 0.75mg/kg versus 0.3 mg/kg


““Steroid Therapy”Steroid Therapy”Prednisone therapy does produce side effects including weight gain, cushingoid appearance and osteopeniaSide effects are dose related and duration relatedRole still remains controversal


““Orthotics”Orthotics”AFO’s and KAFO’s are used when gait becomes precariousKAFO’s are supplemented with a walker to prevent incidents of fallingIshial weightbearing support, posterior thigh cuff and spring loaded drop lock knee joint with fixed ankle joint are key components to brace useExtend ambulation up to three years


““Lower Limb Surgery”Lower Limb Surgery”As muscles weakness worsens, contractures develop and walking becomes labored and unstableSoft tissue surgery can improve gait and prolong the time during which the child is able to ambulateShapiro and Specht et al JBJS 1993 classified surgical type based upon ambulatory approach


“ “Lower Limb Surgery”Lower Limb Surgery”Early-Extensive Ambulatory: release hip, hamstring, heel cords, and PT transfer before contractureModerate Ambulatory: rarely includes the hip and is performed while child is still able to walk but is getting worseMinimum Ambulatory: corrects only the equinus contractures


“ “Lower Limb Surgery”Lower Limb Surgery”Rehabilitative Approach: operative intervention after the child ceases walking but with goal of reestablishing ambulationPalliative Approach: surgical correction of equinovarus after full-time wheelchair use has begun with goal of pain relief and better shoe/orthotic use


“ “Lower Limb Surgery”Lower Limb Surgery”Proponents of surgery site that operating before contractures develop improve the quality of ambulation without braces and wheelchair dependence is delayed ‘Rideau et al’On average, operative approaches prolong walking time by 2 to 3.5 years


“ “Lower Limb Surgery”Lower Limb Surgery”If surgery is delayed until after the child loses the ability to walk, it must be performed in a timely manner to reestablish ambulationThis small window is only three to six months after the child stops ambulatingOperations after this time will not help regain the patients ability to walk


“ “Lower Limb Surgery”Lower Limb Surgery”

Foot and AnkleFoot and AnkleEquinus is managed by percutaneous TendoAchilles lengtheningVarus is treated by anterior transfer of the posterior tibilais tendon through the interosseous membraneThis addresses hindfoot varus and augments dorsiflexion of the ankle


““Lower Limb Surgery”Lower Limb Surgery”

KneeKneeConsists of lengthening or tenotomy of the hamstringsYount procedure helpfulKAFO bracing essential postop


““Lower Limb Surgery”Lower Limb Surgery”

HipHipAbduction contractures of the hips are treated by resection of the iliotibial band ‘Ober Release”Hip flexion contractures can be improved by release of the sartorius, rectus femoris, and tensor fascia lata


““Lower Limb Surgery”Lower Limb Surgery” Postoperative carePostoperative care

Postoperative care should allow for early weightbearing and ambulationStanding position encouraged on the first postoperative dayCasting should be limitedBracing instituted as soon as possible after casting and or surgery


““Spinal Deformities”Spinal Deformities”Prevalence is higher than that of idiopathic scoliosisGreater the neuromuscular involvement the greater the likelihood and severity of the scoliosisCurves tend to become increasingly pronounced after the child is nonambulatory


““Spinal Deformities”Spinal Deformities”Curve patterns are different from idiopathic scoliosisLong and sweeping thoracoclumbar curves extending to the pelvis with pelvic obliquity commonly seenThoracolumbar kyphosis common and sometimes lumbar hyperlordosis can be seen


““Spinal Deformities”Spinal Deformities”Scoliosis develops in 25% of the patients while they are still able to walkCurves that progress to 35 to 40 degree’s will continue to worsenIf left untreated, most curves will progress beyond 90 degree’sAs curves increase,increased difficulty with sitting, increasing pain, and respiratory problems develop


““Spinal Deformities”Spinal Deformities”

Treatment OptionsTreatment OptionsObservationBracingSurgical Stabilization


““Spinal Deformities”Spinal Deformities” BracingBracing

Has been tried but not recommendedUsed only to improve sitting wheelchair postureBracing Premise: prevents progression but all these curves progress despite bracingProgression duration longer in neuromuscular’s due to prolonged muscle weaknessBracing will effect pulmonary status


““Spinal Deformities”Spinal Deformities” SurgerySurgery

Surgical principles are different from those of idiopathic scoliosisPerformed youngerFusion’s are longerCommonly extends to the sacrumAnterior/Posterior fusion’s are common


““Spinal Deformities”Spinal Deformities” SurgerySurgery

Important concept to understand is the centering of the head over the pelvis in both the coronal and sagittal planesMaintains sitting balanceImproves head controlAllows more independent upper extremity control



SurgerySurgerySurgery should be performed once a curve reaches 30 degree’s in a nonambulatorMubarak et al recommend surgery for curves greater than 20 degree’s and when FVC is greater than 40 percent of normalSurgery tolerated if FVC is less than 35% of normal



SurgerySurgeryFusion consists of segmental fixation with sublaminar wiresExtension of the fusion to the pelvis dependent on the presence of pelvic obliquityMubarak et al: mild curve without preexisting pelvic obliquity, fuse to L5 only



SurgerySurgeryBecause the primary goals are to ensure a level pelvis for seating, fusion ‘s are extended to the pelvis via Galveston techniquePelvic obliquity must be controlled and therefore caudal fusion is necessary


“ “Spinal Deformities”Spinal Deformities”

ComplicationsComplicationsRamirez et al: reported a 27% major complication rateSubstantial blood loss due to osteopenic bonePostoperative infectionHardware failureCurve progression


“ “Spinal Deformities”Spinal Deformities”

ComplicationsComplicationsMiller et al: pneumonia occurred in 17% of the patientsProlonged mechanical ventilator dependencyMalignant HyperthermiaSudden Death


THANK YOUTHANK YOU

Dr. Donald W. KucharzykDr. Donald W. Kucharzyk

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Muscular Dystrophies Neuromuscular Scoliosis Dr. Donald W. Kucharzyk Clinical Assistant Professor University of Chicago Children’s Hospital