DefinitionInjury to the brachial plexus during birth.
MechanismOccurs usually due to a stretching injury from a difficult vaginal delivery and in some rare cases reported following C-sections.
- Occus in 1-2/1000 births.
- Associated with stretching or contusion of the brachial plexus. But it is decreasing in frequency due to improved obstetric care.
- Most often right sided or bilateral.
Risk FactorsLarge size of neonate (macrosomia), shoulder dystocia, forceps delivery, breech position, prolonged labor, multiparous pregnancy, difficult presentation.
|Group I (Duchenne-Erb’s Palsy)||C5-C6||Paralysis of deltoid and biceps. Intact wrist and digital flexion/extension.||Best prognosis, most common|
|Group II (Intermediate Paralysis)||C5-C7||Paralysis of deltoid, biceps, and wrist and digital extension. Intact wrist and digital flexion.||Poor prognosis|
|Group III (Total Brachial Plexus Palsy)||C5-T1||Flail extremity without Horner’s syndrome||Worse prognosis|
|Group IV (Total Brachial Plexus Palsy with Horner’s syndrome)||C5-T1||Flail extremity with Horner’s syndrome||Worse prognosis|
SymptomsThe child might have a lack of active hand and arm motion.
- The arm hangs limp at side in an adducted and internally rotated position.
- Decreased shoulder external rotation.
- Affected shoulder subluxates posteriorly
- Stimulate neonatal reflexes including Moro, asymmetric tonic neck and Votja reflexes.
- Pain with gentle shaking of a flail arm may indicate pseudoparalysis from infection or fracture rather than nerve palsy.
- Typically internal rotation shoulder contracture.
- Glenohumeral dysplasia: There is increased glenoid retroversion, humeral head flattening, and posterior humeral head subluxation.
- Progressive glenoid hypoplasia occurs in 70% of children with significant internal rotation contracture.
- Caused by Internal rotation contracture (loss of external rotation).
- Etiology is unclear in elbow flexion contracture. It is likely due to persistent relative triceps weakness (C7) compared with biceps (C5-6).
- Clavicle and humerus fractures.
X-rayUseful for evaluation of clavicle or humerus fractures and the position of the humeral head within the glenoid. There is limited utility in infants due to the minimal ossification of humeral head and glenoid.
- Obtain an axillary lateral view of the shoulder to evaluate position of humeral head if patient is older and there is a high suspicion of joint subluxation.
- It is imortant to prevent posterior subluxation with erosion of the glenoid.
Computer Tomography (CT)If surgical reconstruction of the shoulder is planned consider CT scanning instead of magnetic resonance imaging (MRI).
Magnetic Resonance Imaging (MRI)May be used to distinguish between root avulsion and extraforaminal rupture.
Ultrasound (US)Ultrasound allows for assessment of joint subluxation or dislocation.
EMG/ENoGThese methods have poor reliability and often underestimate the severity of injury.
- It is important to maintain passive ROM and await return of motor function (might take up to 18 months).
- Parents should focus on passive elbow motion and shoulder elevation, abduction, and external rotation.
Operative TreatmentMethod: Early surgery is done to address nerve function. Later on surgery is done to address deformities.
- Microsurgical nerve grafting.
- Latissimus and teres major transfer to shoulder external rotators (L’Episcopo).
- Tendon transfers for elbow flexion (Clark pectoral transfer and Steindler flexorplasty).
- Pectoral and subscapularis release for internal rotation contracture and secondary glenoid hypoplasia (<5 years old).
- Proximal humerus rotational osteotomy (>5 years old).
- Release of the subscapularis tendon for internal rotation contracture, if performed by age 2 years, may result in improved active external rotation of the shoulder, with muscle transfer to assist in active external rotation.
COMPLICATIONS AND PROGNOSIS
ComplicationsInitial nerve inury: Phrenic nerve palsy. Diaphragm plication may be required if persistent .
Surgery: Shoulder tendon transfers with radial and axillary nerve palsies.
Phrenic nerve palsy: If persist may require diaphragm plication.
- More than 90% of cases resolve without intervention. Observe that spontaneous recovery may occur for up to 2 years.
- Erb’s Palsy.
- Complete recovery possible if biceps and deltoid are anti-gravity by 3 months.
- Early twitch biceps activity suggests a favorable outcome.
- Lack of biceps function by 3-6 months after injury.
- Preganglionic injuries (worst prognosis): Meaning avulsions from the cord, which will not spontaneously recover motor function. The patient will have loss of rhomboid function (dorsal scapular nerve) and elevated hemidiaphragm (phrenic nerve).
- Horner syndrome (ptosis, miosis, anhydrosis): Less than 10% recover spontaneous motor function.
- C7 involvement.
- Klumpke palsy.