Brachial Plexus Birth Palsy

Waters and colleagues defined a CT/MRI grading of the glenohumeral deformity that progresses with an untreated internal-rotation contracture. The grade directs whether the joint can be rebalanced with soft tissue alone or needs a bony procedure.

The flaccid or under-moving newborn arm has several mimics. The single most important step is to exclude a painful pseudoparalysis (fracture, infection) before attributing weakness to plexopathy.

Birth plexus palsy rarely occurs in isolation - the same difficult delivery often injures neighbouring structures, and some associations carry prognostic weight.

• Clavicle and humeral fractures: the commonest association; they produce a painful pseudoparalysis that mimics (and can coexist with) the palsy, so always radiograph the shoulder girdle.
• Facial (VII) nerve palsy: from forceps pressure or the same lateral traction; usually neurapraxic and self-limiting.
• Cephalohaematoma / subgaleal haemorrhage and congenital muscular torticollis from the birth trauma.
• Phrenic nerve (C3-C5) palsy with hemidiaphragm paralysis: an important association of high, proximal (C5) and total lesions. Because the phrenic nerve leaves the plexus very proximally, its involvement flags a severe injury at root level (often with avulsion). It can cause neonatal respiratory distress or recurrent atelectasis - look for unexplained respiratory difficulty and confirm with a "sniff test" (fluoroscopy or ultrasound showing paradoxical upward diaphragm motion on inspiration); persistent symptomatic paralysis may need diaphragm plication.

Glenohumeral Dysplasia (GHD): The major late complication. Characterized by:

• Glenoid retroversion.
• Posterior subluxation of humeral head.
• Flattening of humeral head.
• Eventual osteoarthritis.

• Nerve Surgery: Sling/Shoulder Immobilizer. Gentle ROM at 4-6 weeks. Expect recovery over 12-18 months.
• Tendon Transfer/Release: External Rotation Immobilization (Spica or Brace) for 6 weeks. Intensive physio after.
• Osteotomy: Sling. ROM as tolerated. Bone healing in 6-8 weeks.

• Erb's (Type I): Greater than 90% recover good function (Mallet IV-V).
• Total Palsy (Type III/IV): Poor prognosis. Permanent deficits common.
• Nerve Surgery: Improves function significantly but rarely restores normal.
• Long-term: Shoulder problems (GHD, OA) are the main late issues.

Global Epidemiology:

• Incidence approximately 1-2 per 1000 live births, falling in high-resource settings. A Swedish national registry recorded a decline from 3.1 to 1.0 per 1000 cephalic vaginal births between 1997 and 2019 despite rising recognition of shoulder dystocia (PMID 36345990).
• Risk factors: shoulder dystocia, fetal macrosomia, maternal gestational diabetes, instrumental (forceps/vacuum) delivery, prolonged second stage, and breech delivery. Notably, a proportion of cases occur without documented dystocia (including caesarean births), implicating in-utero maladaptation.
• Upper-trunk (Erb's) pattern accounts for roughly 80-90% of cases and carries the best prognosis.

Side-by-Side Guidance:

Service Organisation & Resource Variation:

• High-resource settings: dedicated multidisciplinary plexus clinics (paediatric hand/peripheral-nerve surgery, physiotherapy, occupational therapy), early MRI and microsurgical capability, and structured glenohumeral surveillance.
• Limited-resource settings: emphasis on prevention (dystocia training, gestational diabetes screening), parent-delivered range-of-motion therapy, and clear referral pathways; advanced microsurgery and secondary reconstruction may be regionally centralised or unavailable, making timely triage critical.
• Universal principles: exclude a fracture, protect passive range of motion, document serial active movement, refer early if recovery stalls, and monitor lifelong for shoulder dysplasia regardless of setting.