SUMMARY

• 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.

• Diagnosis is made clinically and depends on the nerve roots involved.

• Treatment can be observation or operative depending on the nerve roots involved, the severity of injury, and the location of the nerve injury.

EPIDEMIOLOGY

• Incidence

  • approximately 1 to 4 per 1,000 live births

  • decreasing in frequency due to improved obstetric care

• Anatomic location

  • often right sided or bilateral

• Risk factors 

   

  • large for gestational age (macrosomia)

  • multiparous pregnancy

  • difficult presentation

  • shoulder dystocia

  • forceps delivery

  • breech position

  • prolonged labor

ETIOLOGY

• Cause

  • usually a stretching injury from a difficult vaginal delivery

  • some rare cases reported following C-sections

• Associated orthopedic conditions

  • glenohumeral dysplasia 

     

    • increased glenoid retroversion, humeral head flattening, posterior humeral head subluxation 

       

      • develops in 70% of infants with obstetric brachial plexopathy

      • caused by Internal rotation contracture (loss of external rotation) 

  • elbow flexion contracture

    • etiology is unclear, likely due to persistent relative triceps weakness (C7) compared with biceps (C5-6)

  • clavicle and humerus fractures

  • torticollis

ANATOMY

• Brachial plexus diagram 

• Narakas Classification
  Group	Characteristics	Roots
  Group I (Duchenne-Erb's Palsy)	Paralysis of deltoid and biceps. Intact wrist and digital flexion/extension.	C5-C6
  Group II (Intermediate Paralysis)	Paralysis of deltoid, biceps, and wrist and digital extension. Intact wrist and digital flexion.	C5-C7
  Group III (Total Brachial Plexus Palsy)	Flail extremity without Horner's syndrome	C5-T1
  Group IV (Total Brachial Plexus Palsy with Horner's syndrome)	Flail extremity with Horner's syndrome	C5-T1

• Waters Classification of Glenohumeral Deformity

• Waters Classification of Glenohumeral Deformity
  Classification	Radiographic features
  Type I	< 5 degree difference in retroversion
  Type II	> 5 degree difference in retroversion
  Type III	Posterior humeral head subluxation < 35% anterior to scapular spine axis
  Type IV	Presence of false glenoid
  Type V	Flattening of humeral head, progressive/ complete humeral head dislocation
  Type VI	Infantile posterior dislocation
  Type VII	Proximal humeral growth arrest

PRESENTATION GENERAL

• Symptoms

  • lack of active hand and arm motion

• Physical exam

  • upper extremity exam

    • arm hangs limp at side in an adducted and internally rotated position

    • decreased shoulder external rotation 

    • affected shoulder subluxates posteriorly

  • provocative testing

    • stimulate neonatal reflexes including Moro, asymmetric tonic neck and Vojta reflexes

    • pain with gentle shaking of a flail arm may indicate pseudoparalysis from infection or fracture rather than nerve palsy

  • Hospital for Sick Children Active Movement Scale (AMS) muscle strength grading system 

    • full range of motion with gravity eliminated (score of 4) must be achieved before higher scores may be assigned

IMAGING

• Radiographs

  • may be useful for evaluation of clavicle or humerus fractures

  • limited utility in infant given minimal ossification of humeral head and glenoid

  • axillary view to evaluate position of humeral head if patient is older and suspicion is high for joint subluxation

• Myelography/CT myelography/MRI

  • may be used to distinguish between root avulsion and extraforaminal rupture

• EMG/NCV

  • poor reliability and often underestimate the severity of injury

• Ultrasound

  • allows for assessment of joint subluxation or dislocation

ERB'S PALSY (C5,6) - UPPER LESION

• Most common type 

   

• Mechanism

  • results from lateral flexion of the head towards the contralateral shoulder with depression of the ipsilateral shoulder producing traction on plexus

    • occurs during difficult delivery in infants

• Physical exam

  • adducted, internally rotated shoulder; pronated forearm, extended elbow (“waiter’s tip”) 

  • C5 deficiency

    • axilllary nerve deficiency

      • deltoid, teres minor weakness

    • suprascapular nerve deficiency

      • supraspinatus, infraspinatus weakness

    • musculocutaneous nerve deficiency

      • biceps and brachialis weakness 

         

  • C6 deficiency

    • radial nerve deficiency

      • brachioradialis, supinator weakness

• Prognosis

  • best prognosis for spontaneous recovery

KLUMPKE'S PALSY (C8,T1) - LOWER LESION

• Mechanism

  • rare in obstetric palsy

  • usually arm presentation with subsequent traction/abduction from trunk

• Physical exam

  • deficit of all of the small muscles of the hand (ulnar and median nerves)

  • “claw hand” 

    • wrist in extreme extension because of the unopposed wrist extensors

    • hyperextension of MCP due to loss of hand intrinsics

    • flexion of IP joints due to loss of hand intrinsics

• Prognosis

  • poor prognosis for spontaneous recovery

  • frequently associated with a preganglionic injury and Horner's Syndrome

TOTAL PLEXUS PALSY (C5-T1)

• Mechanism

  • stretch, rupture, and avulsion injury

• Physical exam

  • flaccid arm

  • both motor and sensory deficits

• Imaging

  • chest radiograph to look for ipsilateral hemidiaphragm paralysis from phrenic nerve injury 

• Prognosis

  • worst prognosis

TREATMENT  - GENERAL

• Nonoperative

  • observation & daily passive exercises by parents 

    • indications

      • first line of treatment for all obstetric brachial plexopathies while awaiting return of function 

         

    • key to treatment is maintaining passive motion while waiting for nerve function to return

• Operative

  • microsurgical nerve grafting 

     

    • indications

      • lack of antigravity biceps function between 3-9 months of age

      • postganglionic injury with intact nerve roots with segmental injury to nerve

    • outcomes

      • improved outcomes are seen with shorter grafts (<10cm)

  • nerve transfer or neurotization

    • definition

      • nerve transfer refers to fascicles from one nerve transferred into a nother nerve that supplies a muscle

      • neurotization refers to placing nerve fascicles directly into a neuromuscular junction of a muscle

    • indications

      • lack of antigravity biceps function between 3-9 months of age

      • preganglionic injury or avulsion of nerve roots

TREATMENT - SHOULDER DISLOCATION & CONTRACTURES

• Operative

  • soft tissue procedures

    • latissimus dorsi and teres major transfer (Hoffer procedure) 

       

      • indication

        • persistent internal rotation contracture or external rotation weakness without glenohumeral dysplasia

      • technique

        • pass tendons posteriorly around humerus to create external rotation forces

    • pectoralis major and +/- subscapularis lengthening

      • indication

        • to lessen the internal rotation forces

      • may be used in conjunction with tendon transfers

    • arthroscopic release for internal rotation contractures

  • bony procedures

    • proximal humeral derotation osteotomy (Wickstrom) 

       

      • indication

        • persistent internal rotation contracture or external rotation weakness with glenohumeral dysplasia

    • arthrodesis

      • indication

        • non-functional deltoid with good function of hand and wrist

TREATMENT  - ELBOW FLEXION CONTRACTURE

• Nonoperative

  • serial nighttime elbow extension splinting 

     

    • indications

      • for elbow flexion contracture <40 degrees

    • outcomes

      • prevents progression, does not correct contracture

  • serial elbow extension casting

    • indications

      • for elbow flexion contracture >40 degrees

• Operative

  • anterior capsular release, biceps/brachialis tendon lengthening

    • indications

      • for severe, persistent contracture

    • outcomes

      • may have high recurrence rate

TREATMENT - FOREARM

• Operative

  • indications

    • residual supination contracture of the forearm

  • technique

    • biceps rerouting tendon transfer

      • intact passive passive pronation

    • Operative

      • indications

        • replace function for a paralyzed muscle

      • force is preportional to cross-sectional area of the muscle

      • amplitude is proportional to the length of the muscle

      • technique

        • tendon transfers

          • wrist drop

            • pronator teres to ECRB

          • loss of finger extension

            • FCR or FCU to EDC 2-5

          • thumb abduction

            • EIP to abductor pollicis brevis

TREATMENT - WRIST AND HAND

• Operative

  • indications

    • replace function for a paralyzed muscle

  • force is preportional to cross-sectional area of the muscle

  • amplitude is proportional to the length of the muscle

  • technique

    • tendon transfers

      • wrist drop

        • pronator teres to ECRB

      • loss of finger extension

        • FCR or FCU to EDC 2-5

      • thumb abduction

        • EIP to abductor pollicis brevis

COMPLICATIONS

• Initial nerve inury

  • phrenic nerve palsy

    • if persistent may require diaphragm plication

• Surgical complications

  • shoulder tendon transfers

    • radial and axillary nerve palsies

• Phrenic nerve palsy

  • if persist may require diaphragm plication