SUMMARY
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Obstetric Brachial Plexopathy is injury to the brachial plexus that occurs during birth usually as a result of a stretching injury from a difficult vaginal delivery.
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Diagnosis is made clinically and depends on the nerve roots involved.
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Treatment can be observation or operative depending on the nerve roots involved, the severity of injury, and the location of the nerve injury.
EPIDEMIOLOGY
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Incidence
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approximately 1 to 4 per 1,000 live births
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decreasing in frequency due to improved obstetric care
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Anatomic location
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often right sided or bilateral
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- Risk factors
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large for gestational age (macrosomia)
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multiparous pregnancy
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difficult presentation
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shoulder dystocia
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forceps delivery
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breech position
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prolonged labor
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ETIOLOGY
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Cause
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usually a stretching injury from a difficult vaginal delivery
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some rare cases reported following C-sections
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Associated orthopedic conditions
- glenohumeral dysplasia
- increased glenoid retroversion, humeral head flattening, posterior humeral head subluxation
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develops in 70% of infants with obstetric brachial plexopathy
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caused by Internal rotation contracture (loss of external rotation)
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- increased glenoid retroversion, humeral head flattening, posterior humeral head subluxation
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elbow flexion contracture
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etiology is unclear, likely due to persistent relative triceps weakness (C7) compared with biceps (C5-6)
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clavicle and humerus fractures
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torticollis
- glenohumeral dysplasia
ANATOMY
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Brachial plexus diagram
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Narakas Classification
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Group
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Characteristics
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Roots
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Group I (Duchenne-Erb's Palsy)
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Paralysis of deltoid and biceps.
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Intact wrist and digital flexion/extension.
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C5-C6
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Group II (Intermediate Paralysis)
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Paralysis of deltoid, biceps, and wrist and digital extension.
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Intact wrist and digital flexion.
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C5-C7
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Group III (Total Brachial Plexus Palsy)
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Flail extremity without Horner's syndrome
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C5-T1
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Group IV (Total Brachial Plexus Palsy with Horner's syndrome)
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Flail extremity with Horner's syndrome
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C5-T1
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Waters Classification of Glenohumeral Deformity
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Waters Classification of Glenohumeral Deformity
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Classification
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Radiographic features
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Type I
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< 5 degree difference in retroversion
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Type II
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> 5 degree difference in retroversion
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Type III
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Posterior humeral head subluxation
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< 35% anterior to scapular spine axis
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Type IV
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Presence of false glenoid
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Type V
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Flattening of humeral head, progressive/ complete humeral head dislocation
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Type VI
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Infantile posterior dislocation
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Type VII
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Proximal humeral growth arrest
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PRESENTATION GENERAL
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Symptoms
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lack of active hand and arm motion
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Physical exam
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upper extremity exam
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arm hangs limp at side in an adducted and internally rotated position
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decreased shoulder external rotation
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affected shoulder subluxates posteriorly
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provocative testing
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stimulate neonatal reflexes including Moro, asymmetric tonic neck and Vojta reflexes
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pain with gentle shaking of a flail arm may indicate pseudoparalysis from infection or fracture rather than nerve palsy
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Hospital for Sick Children Active Movement Scale (AMS) muscle strength grading system
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full range of motion with gravity eliminated (score of 4) must be achieved before higher scores may be assigned
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IMAGING
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Radiographs
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may be useful for evaluation of clavicle or humerus fractures
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limited utility in infant given minimal ossification of humeral head and glenoid
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axillary view to evaluate position of humeral head if patient is older and suspicion is high for joint subluxation
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Myelography/CT myelography/MRI
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may be used to distinguish between root avulsion and extraforaminal rupture
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EMG/NCV
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poor reliability and often underestimate the severity of injury
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Ultrasound
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allows for assessment of joint subluxation or dislocation
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ERB'S PALSY (C5,6) - UPPER LESION
- Most common type
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Mechanism
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results from lateral flexion of the head towards the contralateral shoulder with depression of the ipsilateral shoulder producing traction on plexus
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occurs during difficult delivery in infants
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Physical exam
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adducted, internally rotated shoulder; pronated forearm, extended elbow (“waiter’s tip”)
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C5 deficiency
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axilllary nerve deficiency
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deltoid, teres minor weakness
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suprascapular nerve deficiency
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supraspinatus, infraspinatus weakness
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musculocutaneous nerve deficiency
- biceps and brachialis weakness
- biceps and brachialis weakness
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C6 deficiency
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radial nerve deficiency
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brachioradialis, supinator weakness
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Prognosis
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best prognosis for spontaneous recovery
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KLUMPKE'S PALSY (C8,T1) - LOWER LESION
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Mechanism
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rare in obstetric palsy
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usually arm presentation with subsequent traction/abduction from trunk
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Physical exam
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deficit of all of the small muscles of the hand (ulnar and median nerves)
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“claw hand”
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wrist in extreme extension because of the unopposed wrist extensors
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hyperextension of MCP due to loss of hand intrinsics
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flexion of IP joints due to loss of hand intrinsics
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Prognosis
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poor prognosis for spontaneous recovery
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frequently associated with a preganglionic injury and Horner's Syndrome
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TOTAL PLEXUS PALSY (C5-T1)
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Mechanism
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stretch, rupture, and avulsion injury
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Physical exam
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flaccid arm
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both motor and sensory deficits
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Imaging
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chest radiograph to look for ipsilateral hemidiaphragm paralysis from phrenic nerve injury
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Prognosis
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worst prognosis
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TREATMENT - GENERAL
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Nonoperative
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observation & daily passive exercises by parents
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indications
- first line of treatment for all obstetric brachial plexopathies while awaiting return of function
- first line of treatment for all obstetric brachial plexopathies while awaiting return of function
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key to treatment is maintaining passive motion while waiting for nerve function to return
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Operative
- microsurgical nerve grafting
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indications
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lack of antigravity biceps function between 3-9 months of age
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postganglionic injury with intact nerve roots with segmental injury to nerve
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outcomes
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improved outcomes are seen with shorter grafts (<10cm)
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nerve transfer or neurotization
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definition
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nerve transfer refers to fascicles from one nerve transferred into a nother nerve that supplies a muscle
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neurotization refers to placing nerve fascicles directly into a neuromuscular junction of a muscle
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indications
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lack of antigravity biceps function between 3-9 months of age
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preganglionic injury or avulsion of nerve roots
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- microsurgical nerve grafting
TREATMENT - SHOULDER DISLOCATION & CONTRACTURES
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Operative
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soft tissue procedures
- latissimus dorsi and teres major transfer (Hoffer procedure)
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indication
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persistent internal rotation contracture or external rotation weakness without glenohumeral dysplasia
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technique
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pass tendons posteriorly around humerus to create external rotation forces
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pectoralis major and +/- subscapularis lengthening
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indication
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to lessen the internal rotation forces
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may be used in conjunction with tendon transfers
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arthroscopic release for internal rotation contractures
- latissimus dorsi and teres major transfer (Hoffer procedure)
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bony procedures
- proximal humeral derotation osteotomy (Wickstrom)
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indication
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persistent internal rotation contracture or external rotation weakness with glenohumeral dysplasia
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arthrodesis
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indication
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non-functional deltoid with good function of hand and wrist
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- proximal humeral derotation osteotomy (Wickstrom)
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TREATMENT - ELBOW FLEXION CONTRACTURE
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Nonoperative
- serial nighttime elbow extension splinting
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indications
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for elbow flexion contracture <40 degrees
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outcomes
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prevents progression, does not correct contracture
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serial elbow extension casting
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indications
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for elbow flexion contracture >40 degrees
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- serial nighttime elbow extension splinting
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Operative
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anterior capsular release, biceps/brachialis tendon lengthening
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indications
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for severe, persistent contracture
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outcomes
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may have high recurrence rate
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TREATMENT - FOREARM
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Operative
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indications
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residual supination contracture of the forearm
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technique
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biceps rerouting tendon transfer
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intact passive passive pronation
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Operative
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indications
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replace function for a paralyzed muscle
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force is preportional to cross-sectional area of the muscle
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amplitude is proportional to the length of the muscle
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technique
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tendon transfers
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wrist drop
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pronator teres to ECRB
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loss of finger extension
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FCR or FCU to EDC 2-5
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thumb abduction
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EIP to abductor pollicis brevis
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TREATMENT - WRIST AND HAND
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Operative
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indications
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replace function for a paralyzed muscle
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force is preportional to cross-sectional area of the muscle
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amplitude is proportional to the length of the muscle
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technique
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tendon transfers
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wrist drop
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pronator teres to ECRB
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loss of finger extension
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FCR or FCU to EDC 2-5
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thumb abduction
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EIP to abductor pollicis brevis
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COMPLICATIONS
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Initial nerve inury
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phrenic nerve palsy
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if persistent may require diaphragm plication
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Surgical complications
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shoulder tendon transfers
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radial and axillary nerve palsies
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Phrenic nerve palsy
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if persist may require diaphragm plication
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