Obstetric Brachial Plexus Palsy — Reconstruction

The core decision. Obstetric brachial plexus injury (OBPI) is reconstructed surgically only when spontaneous recovery is clearly inadequate. The whole strategy pivots on one observation — does the biceps recover antigravity function by 3-6 months? If it does not, primary nerve reconstruction is indicated. If recovery plateaus later with residual deficits, secondary procedures (tendon transfers, soft-tissue releases, osteotomy) take over. The operations on this page fall into those two groups: primary nerve reconstruction (neuroma excision with sural nerve grafting, and nerve transfers) and secondary reconstruction (subscapularis release, the modified L'Episcopo transfer, and humeral derotation osteotomy). Absolute indications for primary nerve reconstruction - No antigravity biceps (MRC Grade less than 3) at 3 months of age — the most widely accepted criterion (Narakas, Gilbert).

• Total plexus palsy (C5-T1) with Horner's syndrome — indicates preganglionic avulsion of C8-T1; negligible spontaneous recovery; operate at 2-3 months.
• Total plexus palsy without Horner's — explore at 3 months if there is no antigravity elbow flexion.
• Complete flail limb with no recovery at 1 month — early exploration may be indicated. Relative indications - Extended Erb's palsy (C5-7) with no biceps recovery at 4-6 months.
• Isolated C5-6 palsy with no biceps at 4-6 months but some shoulder recovery — observe to 6 months if improvement is progressive.
• Recovery plateau before antigravity strength is achieved in key muscle groups. Contraindications. Absolute: active local infection at the surgical site, uncorrected coagulopathy, or significant cardiopulmonary comorbidity precluding general anaesthesia. Relative: late presentation beyond 12-18 months (nerve grafting is less effective — prefer nerve transfers), an isolated upper trunk palsy with clearly progressive biceps recovery (continue observation), or family non-compliance with the post-operative therapy programme. Indications for secondary reconstruction. Once primary recovery has plateaued (typically 18-24 months after reconstruction, or in a child managed non-operatively), residual deficits are addressed by procedure: - Internal rotation and adduction contracture (the most common residuum): - Subscapularis release — for passive external rotation less than 20-30 degrees with the shoulder in adduction, in a child aged 2-4 years. - Modified L'Episcopo transfer (latissimus dorsi and teres major to the rotator cuff) — when passive external rotation is preserved but active external rotation is absent, in a child aged 3-8 years. Do not perform it if the infraspinatus is already active (MRC Grade 4 or greater), as the transfer may overcorrect. - Humeral derotation osteotomy — for a fixed internal rotation deformity with a congruent glenohumeral joint (Waters Grade I-II), typically in children older than 4-5 years, or when soft-tissue releases have failed.
• Elbow flexion deficit (less common): - Oberlin transfer (ulnar fascicle to biceps motor branch) — for persistent elbow flexion weakness after failed primary reconstruction, or when primary grafting was not possible. - Steindler flexorplasty — proximal transfer of the common flexor origin for residual elbow flexion weakness. - Triceps-to-biceps transfer — when the triceps is strong (MRC Grade 4 or greater), the elbow flexors are absent, and other options are unavailable.

Consent. Counsel parents specifically on the guarded prognosis in total plexus palsy (especially with Horner's), the small risk of phrenic nerve injury and haemidiaphragm paralysis, donor-site morbidity (sural nerve numbness; trapezius weakness after spinal accessory harvest), a small patch of shoulder anaesthesia from supraclavicular nerve division, and the likelihood that secondary procedures will be needed later. Setup. Supine with a sandbag or roll under the ipsilateral shoulder and the head turned to the opposite side; the arm is draped free for intra-operative manipulation. General anaesthesia without long-acting neuromuscular blockade so a nerve stimulator can identify structures; the anaesthetist watches for phrenic stimulation. A tourniquet is not routinely needed (a thigh tourniquet at 250 mmHg may help simultaneous sural harvest by a second team). Equipment: operating microscope (10-25x), microsurgical instruments, a constant-current nerve stimulator (0.5-2 mA), 8-0 or 9-0 nylon, and fibrin glue.

The goal of primary reconstruction is to expose the plexus, excise the non-conducting neuroma back to healthy fascicles, and bridge the gap with reversed sural nerve cable grafts — protecting the phrenic nerve throughout. Nerve transfers and secondary procedures are then built on the same anatomical exposures. The exposure is laid out in full as the first steps below.

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After primary nerve reconstruction. The arm is immobilised in a collar and cuff or soft sling for 3-4 weeks to protect the coaptations (a soft cervical collar for the first week if the repair was under tension). Analgesia is paracetamol and NSAIDs, with opioids sparingly. A daily neurological examination for 48 hours documents active movement of shoulder, elbow, wrist and hand, and a chest X-ray excludes pneumothorax or haemidiaphragm elevation. Gentle passive range of motion of shoulder, elbow and hand begins on day 1, but the shoulder is kept in neutral rotation and adduction for the first 3-4 weeks. After 3-4 weeks immobilisation is weaned and passive stretching (especially external rotation and abduction) is escalated with formal physiotherapy 2-3 times weekly; parents perform daily passive exercises. The first EMG signs of reinnervation appear at 4-8 months. Biceps reinnervation is usually seen first (6-12 months), then shoulder abductors (6-12 months), then forearm and hand muscles (12-24 months); recovery plateaus by 18-24 months, when the need for secondary reconstruction is reassessed. After nerve transfers. The elbow is immobilised in 60-90 degrees of flexion for 3-4 weeks after an Oberlin transfer; the shoulder in 30-45 degrees of abduction after a SAN-to-SSN transfer. Gradual weaning over weeks 4-6 progresses from passive to active-assisted to active movement. Oberlin reinnervation appears at 3-6 months with functional elbow flexion (MRC Grade 3 or better) by 6-12 months; SAN-to-SSN external rotation appears at 6-12 months. After secondary procedures. Subscapularis release: abduction-external rotation splint for 4-6 weeks, then passive and active-assisted external rotation (internal rotation returns spontaneously). Modified L'Episcopo: abduction/external rotation brace for 4-6 weeks; weeks 6-12 active-assisted abduction and external rotation with no active internal rotation or adduction against resistance for 12 weeks; the child then learns to fire the transferred latissimus and teres major through abduction and external rotation. Humeral derotation osteotomy: sling for 4-6 weeks, protected passive motion from day 1, active motion at 6 weeks. Long-term surveillance. All children with OBPI require follow-up until skeletal maturity, regardless of initial treatment. | Age | Assessment | Key concerns | |-----|-----------|--------------| | Birth to 6 months | Monthly motor examination (AMS / Toronto scale), passive ROM; X-ray clavicle/humerus at presentation | Exclude pseudopalsy; document recovery trajectory; identify surgical candidates | | 6 months to 2 years | Every 3-6 months: motor examination, passive ROM, joint contractures | Monitor recovery after primary reconstruction; begin passive stretching for contractures | | 2-5 years | Annual: motor function, Mallet score, passive ROM, shoulder X-ray (± MRI if concern) | Detect glenohumeral dysplasia early; consider secondary reconstruction | | 5 years to skeletal maturity | Annual: functional assessment, limb length, shoulder X-ray (± MRI), patient-reported outcomes (PODCI, DASH) | Monitor growth-related change, limb length discrepancy, late degeneration | | Mature skeleton | Discharge with vocational advice | Functional outcome is stable | Outcomes. After primary reconstruction: C5-6 (Erb's) palsy achieves functional shoulder abduction (greater than 90 degrees) and elbow flexion (MRC Grade 3 or better) in 80-90 percent — external rotation is the most commonly incomplete recovery; total plexus without Horner's achieves functional elbow flexion in about 60-70 percent with variable hand function; total plexus with Horner's is the most challenging group, with fewer than 40 percent achieving useful hand function. After secondary reconstruction: subscapularis release gains 30-50 degrees of passive external rotation (best before age 3 and before dysplasia becomes fixed); the modified L'Episcopo transfer gives active external rotation greater than 30 degrees in 70-80 percent (best when combined with subscapularis release and performed before age 6); humeral derotation osteotomy reliably gives 30-45 degrees of correction with high cosmetic and functional satisfaction.

Critical decision points and danger zones

Epidemiology. Obstetric brachial plexus injury occurs in roughly 1-3 per 1000 live births. The principal risk factors are shoulder dystocia, fetal macrosomia (greater than 4 kg), prolonged second stage, and instrumental (vacuum or forceps) delivery. Upper trunk (C5-6, Erb-Duchenne) injuries predominate and carry the best prognosis; total plexus injuries, especially with Horner's, carry the worst. Narakas classification. A practical four-group scheme that predicts prognosis from the affected roots.

The brachial plexus — structural levels. The plexus is formed by the ventral primary rami of C5-T1 and is divided into five levels. | Level | Structure | Key branches | Notes | |-------|-----------|--------------|-------| | Roots | C5, C6, C7, C8, T1 | Dorsal scapular (C5), long thoracic (C5-7), phrenic contributions (C3-5) | Emerge between anterior and middle scalenes | | Trunks | Upper (C5-6), Middle (C7), Lower (C8-T1) | Suprascapular (C5-6), nerve to subclavius (C5-6) | Lie in the posterior triangle (supraclavicular) | | Divisions | Anterior and posterior of each trunk | None | Lie behind the clavicle (retroclavicular) | | Cords | Lateral, Posterior, Medial | Lateral (C5-7): musculocutaneous, lateral root of median. Posterior (C5-T1): axillary, radial, subscapulars, thoracodorsal. Medial (C8-T1): ulnar, medial root of median, medial cutaneous nerves | Arranged around the axillary artery (infraclavicular) | | Branches | Musculocutaneous, axillary, radial, median, ulnar | — | Final motor innervation to the limb | Clinical relevance in OBPI. The upper trunk (C5-6) is the most commonly injured segment in birth palsy, because of the greater angle of the C5-6 roots as they exit the spinal canal and the fixity of the lower trunk by the transverse cervical ligament. Erb's point — where C5 and C6 unite to form the upper trunk, 2-3 cm above the clavicle at the posterior border of the sternocleidomastoid — is the most common site of neuroma formation and the centrepiece of the supraclavicular exposure. Glenohumeral dysplasia — Waters classification. Graded on MRI or arthrography; it determines whether soft tissue reconstruction alone will correct the shoulder.

Donor and recipient nerve anatomy for transfers. The spinal accessory nerve (CN XI) emerges from the jugular foramen, descends in the posterior triangle superficial to the prevertebral fascia, and divides into a proximal branch (upper trapezius — preserved) and a distal branch (middle and lower trapezius — the donor), identified about 2 cm above the clavicle at the anterior border of the trapezius. The suprascapular nerve arises from the upper trunk at Erb's point and passes through the suprascapular notch to supply supraspinatus and infraspinatus; in the SAN-to-SSN transfer it is divided just distal to its take-off and coapted to the descending accessory branch. For the Oberlin transfer, the musculocutaneous nerve pierces coracobrachialis and gives off the biceps motor branch 5-8 cm distal to the acromion on the deep medial surface of biceps; the ulnar nerve lies medial to the brachial artery in the mid-arm, and its FCU fascicles (synergistic with grip, well compensated) are the safest donors. Danger zones at dissection. Supraclavicular: phrenic nerve (anterior scalene), long thoracic nerve (C5-7, posterior to the plexus on serratus anterior), the transverse cervical and suprascapular arteries crossing the field, the dorsal scapular nerve (C5), and the vertebral vessels deep and medial at the C5-6 foramen level. Infraclavicular/axillary: the axillary artery (cords arranged around it, deep to pectoralis minor), the cephalic vein in the deltopectoral groove, and the medial cutaneous nerves of arm and forearm running with the medial cord. Key evidence. Gilbert and Tassin (1984) established microsurgical repair and the 3-month biceps criterion. Waters (1999) confirmed prospectively that microsurgical repair improves Mallet scores in children without biceps recovery by 3 months, while those recovering biceps by 3 months do well without surgery. Oberlin (1994) described the ulnar-fascicle-to-biceps transfer, now standard for elbow flexion. Waters and Bae showed that humeral derotation osteotomy (2006) and tendon transfer with subscapularis release (2008) improve shoulder function and can partially reverse dysplasia when performed early (before age 4). These studies underpin the timing and procedure choices above and are detailed in the References.