Brachial Plexus Exploration and Reconstruction

Surgical Indications

Timing of Exploration

• Sharp or penetrating injury: explore within days to 2 weeks — primary repair or early grafting possible before retraction
• Closed traction injury without recovery: explore at 3 to 6 months — allows time for neurapraxia resolution while remaining within reinnervation window
• Complete flail arm with imaging and EMG confirming avulsion: proceed to exploration and transfer planning at 3 months
• Progressive neurological deficit or expanding haematoma: urgent exploration regardless of mechanism

Absolute Indications

• Traumatic root avulsion confirmed by pseudomeningoceles, preserved SNAPs, and paraspinal denervation
• Postganglionic rupture with no clinical or electrodiagnostic recovery by 3-6 months
• Associated vascular injury requiring repair with plexus exploration

Relative Indications

• Incomplete recovery with plateau on serial examinations and EMG
• Patient desire for reconstruction after informed discussion of realistic outcomes and donor morbidity
• Paediatric brachial plexus palsy failing to show spontaneous recovery by 3-6 months

Contraindications

Absolute:

• Life-threatening associated injuries precluding prolonged anaesthesia
• Complete motor endplate degeneration beyond 18-24 months with no viable targets
• Patient refusal or inability to comply with postoperative rehabilitation

Relative:

• Isolated neurapraxia expected to recover spontaneously (serial EMG shows improving conduction)
• Poor donor nerve availability or medical comorbidities increasing surgical risk

Evidence Base

Timing and Outcomes

• Early exploration (less than 3 months) for closed injuries risks operating on neurapraxia that would recover; delayed exploration beyond 6-9 months yields poorer axon regeneration due to endplate fibrosis
• Nerve transfer success for elbow flexion (Oberlin) reaches 80-95 percent MRC grade 3 or better when performed within 6 months
• Intercostal nerve transfers achieve useful elbow flexion in 60-75 percent of cases but with higher donor-site morbidity

Graft versus Transfer

• Sural nerve grafting of postganglionic ruptures restores shoulder and elbow function in 60-80 percent when gaps are short and repair is tension-free
• Root avulsions require transfers because no proximal stump exists; spinal accessory to suprascapular and Oberlin transfers are the workhorse procedures with the strongest evidence

Brachial Plexus Anatomy Relevant to Exploration

Roots and Trunks (Supraclavicular)

• C5 and C6 roots emerge between anterior and middle scalene; C7, C8, T1 lie deeper
• Upper trunk is formed by C5-C6 union and lies superficial in the posterior triangle
• Middle trunk (C7) and lower trunk (C8-T1) are progressively deeper and closer to subclavian vessels
• Dorsal scapular nerve (C5) and long thoracic nerve (C5-C7) arise proximally; their denervation confirms preganglionic injury

Divisions and Cords (Infraclavicular)

• Divisions lie behind the clavicle; cords surround the axillary artery in the deltopectoral groove
• Lateral cord gives musculocutaneous and lateral pectoral nerves
• Posterior cord gives axillary and radial nerves
• Medial cord gives ulnar, medial pectoral, and medial cutaneous nerves of arm and forearm

Critical Structures at Risk

• Phrenic nerve on anterior scalene surface — division causes permanent hemidiaphragm paralysis
• Subclavian artery and vein lie anterior and inferior to lower trunk — vascular control mandatory
• Spinal accessory nerve at posterior border of SCM — donor for suprascapular transfer but donor morbidity must be minimised

Supraclavicular Approach

• Incision: transverse or L-shaped along posterior border of SCM from mastoid to clavicle, then laterally
• Divide platysma and identify external jugular vein
• Retract SCM laterally; identify and protect phrenic nerve on anterior scalene
• Divide anterior scalene to expose roots and trunks
• Obtain proximal and distal subclavian vessel control before plexus manipulation

Infraclavicular Approach

• Incision: deltopectoral groove extending from coracoid to axilla
• Develop deltopectoral interval; ligate cephalic vein tributaries
• Divide pectoralis minor from coracoid to expose cords around axillary artery
• May require clavicular osteotomy or division for combined supra-infraclavicular access

Positioning and Preparation

Patient position: Supine, head turned away from operative side, arm abducted 30-45 degrees on arm board. Prep and drape entire arm, neck, chest, and both legs for sural harvest. Foley catheter and arterial line recommended for prolonged procedure.

Anaesthesia: General endotracheal with muscle relaxant only for induction — no paralytics during nerve stimulation phase. Intraoperative nerve monitoring setup with direct stimulation available.

Equipment: Loupe magnification (3.5x) or operating microscope, bipolar cautery, nerve stimulator, vessel loops, microsurgical instruments, sural nerve harvest set.

Consent discussion: Realistic expectations of partial recovery, donor morbidity (sural sensory loss, spinal accessory shoulder droop, ulnar weakness), multiple procedures, and 12-24 month rehabilitation timeline.

Supraclavicular Exploration — Step-by-Step

Step 1: Incision and Superficial Exposure

Make a transverse incision 2 cm above the clavicle from the posterior border of SCM laterally toward the trapezius. Divide platysma. Identify and ligate external jugular vein branches. Retract SCM laterally.

Step 2: Phrenic Nerve Identification and Protection

Identify the phrenic nerve on the anterior scalene surface — it courses obliquely from lateral to medial and contracts with respiration. Place a vessel loop and protect throughout. Division produces permanent hemidiaphragm paralysis.

Step 3: Anterior Scalene Division and Root Exposure

Divide the anterior scalene muscle transversely, protecting the phrenic nerve. Expose the C5 and C6 roots forming the upper trunk. Identify C7, C8, and T1 deeper and more medially. Note any neuromas or ruptures.

Step 4: Vascular Control

Identify the subclavian artery and vein anterior and inferior to the lower trunk. Obtain proximal and distal control with vessel loops before any further plexus dissection. Vascular injury is the most immediate life-threatening complication.

Step 5: Intraoperative Assessment and Stimulation

Perform direct nerve stimulation of each root and trunk. Postganglionic rupture produces distal muscle contraction; avulsed roots produce no response. Document findings. Send sural SNAP if not already obtained preoperatively.

Step 6: Decision for Reconstruction

• Postganglionic rupture with viable stump: sural nerve grafting
• Preganglionic avulsion: nerve transfers (spinal accessory to suprascapular, Oberlin, intercostal)
• Mixed pattern: combine grafting and transfers according to available donors and targets

Nerve Transfer Techniques

Spinal Accessory to Suprascapular Transfer

Identify spinal accessory nerve at posterior border of SCM, 2-3 cm above clavicle. Harvest only the distal branch to trapezius, leaving proximal branch intact. Coapt to suprascapular nerve in the supraclavicular fossa. Restores shoulder abduction and external rotation with minimal donor morbidity.

Oberlin Ulnar Fascicle to Biceps Transfer (or Double Fascicular)

Incision in upper arm medial to biceps. Identify median and ulnar nerves. Stimulate ulnar fascicles to select the largest motor fascicle producing strong wrist flexion without intrinsic hand weakness. Divide and transfer to biceps motor branch. For double fascicular, add median nerve fascicle to brachialis.

Intercostal Nerve Transfers

Harvest 3-4 intercostal nerves (T3-T6) through a separate chest incision or extension of the axillary approach. Coapt to musculocutaneous, axillary, or radial nerve targets. Useful when other donors exhausted; donor morbidity includes chest wall numbness and potential respiratory compromise.

Intraoperative and Early Complications

Vascular Injury

Incidence: 1-3 percent during supraclavicular exposure. Recognition: sudden bleeding, loss of distal pulse. Prevention: obtain proximal and distal subclavian control before plexus dissection. Management: immediate vascular repair or shunt; involve vascular surgery early.

Phrenic Nerve Injury

Incidence: 2-5 percent. Recognition: postoperative elevated hemidiaphragm on chest radiograph, dyspnoea. Prevention: identify and protect phrenic throughout anterior scalene division. Management: supportive; permanent paralysis if complete division.

Horner Syndrome

Incidence: 5-10 percent with lower trunk or T1 root manipulation. Recognition: ptosis, miosis, anhidrosis. Prevention: gentle handling near stellate ganglion. Usually transient; permanent if root avulsion at T1.

Spinal Accessory Donor Deficit

Incidence: 5-15 percent with complete harvest. Recognition: shoulder droop, scapular winging, difficulty with overhead activity. Prevention: harvest only distal branch, leave proximal trapezius innervation intact. Management: physical therapy; rarely requires scapulothoracic fusion.

Late Complications and Failure Modes

Incomplete Recovery or Failed Reinnervation

Incidence: 20-40 percent depending on injury pattern and timing. Recognition: plateau in motor recovery before MRC grade 3. Prevention: operate within 6 months, ensure tension-free coaptations, protect against postoperative stretch. Management: consider secondary tendon transfers or arthrodesis for shoulder and elbow.

Neuroma Formation and Neuropathic Pain

Incidence: 10-20 percent. Recognition: tender Tinel sign at repair site, burning or shooting pain. Prevention: careful handling, tension-free repair, bury proximal stump in muscle if avulsion. Management: neuropathic medications, nerve capping or relocation, spinal cord stimulation in refractory cases.

Donor-Site Morbidity

Sural nerve: permanent lateral foot numbness (universal), occasional painful neuroma (5 percent). Ulnar fascicle: transient or permanent intrinsic weakness if incorrect fascicle selected. Intercostal: chest wall anaesthesia, reduced respiratory reserve.

Infection and Wound Complications

Incidence less than 2 percent. Management: standard wound care, antibiotics, possible return to theatre for washout if deep infection around grafts.

Postoperative Protocol

Immediate Phase (0-6 weeks)

• Immobilise shoulder in abduction sling or brace for 4-6 weeks to protect transfers and grafts
• Gentle passive range of motion of elbow, wrist, and hand from day 1 to prevent stiffness
• No active shoulder or elbow loading until 6 weeks
• Wound care, oedema control, and scar massage begin at 2 weeks

Reinnervation Phase (6 weeks to 6 months)

• Begin active-assisted range of motion once transfers protected
• Electrical stimulation of target muscles once reinnervation detected clinically or by EMG
• Progressive strengthening once MRC grade 3 achieved
• Serial clinical and electrodiagnostic monitoring every 3 months

Functional Phase (6-24 months)

• Task-specific training for shoulder stability, elbow flexion, and hand function
• Consider secondary procedures (tendon transfers, arthrodesis) once reinnervation plateaus
• Psychological support for chronic pain and adjustment to residual disability

Reconstructive Priorities

1. Shoulder stability and external rotation (spinal accessory to suprascapular)
2. Elbow flexion (Oberlin or double fascicular transfer)
3. Shoulder abduction (axillary nerve grafting or transfer)
4. Hand sensation and basic grasp (intercostal or contralateral C7 if available)
5. Wrist and finger extension if donors remain

Expected Outcomes

• Elbow flexion MRC grade 3 or better: 80-95 percent with Oberlin transfer within 6 months
• Shoulder abduction greater than 30 degrees: 60-75 percent with spinal accessory transfer
• Useful hand function: 30-50 percent with multiple transfers; many patients achieve only protective sensation
• Overall patient satisfaction: 60-70 percent report meaningful functional improvement despite incomplete recovery