| Introduction |
 Traumatic brachial plexus injuries (BPIs) can involve any degree of injury at any level of the plexus
- more severe injury such as rupture of plexal segments or root avulsions are associated with higher energy trauma
- Brachial Plexus injuries include
- traumatic injury (this topic)
- obstetric brachial plexus injury
- Erb's palsy
- Klumpke palsy
- burners and stingers
- Parsonage-Turner Syndrome
- Epidemiology
- supraclavicular injuries
- complete involvement of all roots is most common
- 75%-80% of traumatic BPIs
- C5 and C6 upper trunk (Erb palsy)
- 20%-25% of traumatic BPIs
- C8, T1 or lower (Klumpke palsy)
- 0.6%-3.0% of traumatic BPIs
- Mechanism
- high speed vehicular accidents (mostly motorcycle)
- caudally forced shoulder
- predominantly affect upper brachial plexus
- with high enough energy all roots can be affected
- forced arm abduction (as in grabbing onto something while falling)
- predominantly affects lower roots
- Prognosis
- recovery of reconstructed plexus can take up to 3 years
- nerve regeneration occurs at speed of 1mm/day
- infraclavicular plexus injuries have better prognosis than supraclavicular injuries
- upper plexus injuries have improved prognosis
- preservation of hand function
- root avulsion (preganglionic injuries) have worst prognosis
- other surgeries such as arthrodesis and tendon transfers may be needed
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| Anatomy |
- Anatomy
- brachial plexus motor and sensory innervation
 
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| Classification |
- Preganglionic vs. postganglionic
- preganglionic
- avulsion proximal to dorsal root ganglion
- involves CNS which does not regenerate – little potential recovery of motor function (poor prognosis)
- lesions suggesting preganglionic injury:
- Horner’s syndrome
- disruption of sympathetic chain
- winged scapula medially
- loss of serratus anterior (long thoracic nerve) rhomboids (dorsal scapular nerve) leads to medial winging (inferior border goes medial)
- presents with motor deficits (flail arm)
- sensory deficits
- absence of a Tinel sign or tenderness to percussion in the neck
- normal histamine test (C8-T1 sympathetic ganglion)
- intact triple response (redness, wheal, flare)
- elevated hemidiaphragm (phrenic nerve
- rhomboid paralysis (dorsal scapular nerve)
- supraspinatus/infraspinatus (suprascapular nerve)
- latissimus dorsi (thoracodorsal)
- evaluation
- EMG may show loss of innervation to cervical paraspinals
- postganglionic
- involve PNS, capable of regeneration (better prognosis)
- presentation
- presents with motor deficit (flail arm)
- sensory deficits
- evaluation
- EMG shows maintained innervation to cervical paraspinals
- abnormal histamine test
- only redness and wheal, but NO flare
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| Classification Based on Location |
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Upper Lesion: Erb's Palsy (C5,6)
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Introduction
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Physical Exam
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- Most common obstetric brachial plexopathy
- Results from excessive displacement of head to opposite side and depression of shoulder on same side producing traction on plexus
- Occurs during difficult delivery in infants or fall onto shoulder in adults
- Best prognosis
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- Clinically, arm will be adducted, internally rotated, at shoulder; pronated, extended at elbow (“waiter’s tip”)
- C5 deficiency
- axillary nerve deficiency (weakness in deltoid, teres minor)
- suprascapular nerve deficiency (weakness in supraspinatus, infraspinatus)
- musculocutaneous nerve deficiency (weakness to biceps)
- C6 deficiency
- radial nerve deficiency (weakness in brachioradialis, supinator)
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Lower Lesion: Klumpke Palsy (C8,T1)
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- Rare in obstetric palsy
- Usually avulsion injuries caused by excessive abduction (person falling from height clutching on object to save himself)
- Other causes may include cervical rib, or lung mets in lower deep cervical lymph nodes
- Frequently associated with a preganglion injury and Horner's Syndrome
- Poor prognosis
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- Deficit of all of the small muscles of the hand (ulnar and median nerves)
- Clinically, presents as “claw hand”
- wrist held 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
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Total Palsy (C5-T1)
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- A form of brachial plexopathy
- Worst prognosis
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- Leads to a flaccid arm
- Involves both motor and sensory
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| Presentation |
- History
- Physical exam
- Horner's syndrome
- features include
- drooping of the left eyelid
- pupillary constriction
- anhidrosis
- usually show up three days after injury
- represents disruption of sympathetic chain via C8 and/or T1 root avulsions
- severe pain in anesthetized limb
- correlates with root avulsion
- important muscles to test
- serratus anterior (long thoracic nerve) and rhomboids (dorsal scapular nerve)
- if they are functioning then it is more likely the C5 injury is postganglionic
- pulses
- check radial, ulnar and brachial pulses
- arterial injuries common with complete BPIs
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| Imaging |
- Radiographs
- chest radiograph
- recommended views
- fractures to the first or second ribs suggest damage to the overlying brachial plexus
- evidence of old rib fractures can be important in case intercostal nerve is needed for nerve transfer
- inspiration and expiration can demonstrate a paralyzed diaphragm (indicates upper nerve root injury)
- cervical spine series
- recommended views
- transverse process fracture likely indicates a root avulsion
- scapular and shoulder series
- recommended views
- at least AP and axillary (or equivalent)
- scapulothoracic dissociation is associated with root avulsion and major vascular injury
- clavicle
- recommended views
- fracture may indicate brachial plexus injury
- CT myelography
- indications
- gold standard for defining level of nerve root injury
- avulsion of cervical root causes dural sheath to heal with meningocele
- scan should be done 3-4 weeks after injury
- allows blood clot in the injured area to dissipate and meningocele to form
- MRI
- indications
- suspect injury is distal to nerve roots
- can visualize much of the brachial plexus
- CT/myelogram demonstrates only nerve root injury
- findings
- traumatic neuromas and edema
- mass lesions in nontraumatic neuropathy of brachial plexus and its branches
- consistent with injury include
- pseudomeningocele (T1 highlights water content present in a pseudomeningocele )
- empty nerve root sleeves (T2 images highlight fat content nerve roots and empty sleeves)
- cord shift away from midline (T2 highlights fat of cord)
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| Studies |
- Electromyography (EMG)
- tests muscles at rest and during activity
- fibrillation potentials (denervation changes)
- as early as 10-14 days following injury in proximal muscles
- as late as 3-6 weeks in distal muscles
- can help distinguish preganglionic from postganglionic
- examine proximally innervated muscles that are innervated by root level motor branches
- rhomboids
- serratus anterior
- cervical paraspinals
- Nerve conduction velocity (NCV)
- performed along with EMG
- measures sensory nerve action potentials (SNAPs)
- distinguishes preganglionic from postganglionic
- SNAPs preserved in lesions proximal to dorsal root ganglia
- cell body found in dorsal root ganglia
- if SNAP normal and patient insensate in ulnar nerve distribution
- preganglionic injury to C8 and T1
- if SNAP normal and patient insensate in median nerve distribution
- preganglionic injury to C5 and C6
- Nerve action potential (NAPs)
- often intraoperative
- tests a nerve across a lesion
- if NAP positive across a lesion
- preserved axons
- or significant regeneration
- can detect reinnervation months before EMG
- NAP negative-neuropraxic lesion
- NAP positive- axonotmetic lesion
- Sensory and Motor Evoked Potential
- more sensitive than EMG and NCV at identifying continuity of roots with spinal cord (positive finding)
- a negative finding can not differentiate location of discontinuity (root avulsion vs. axonotmesis)
- perform 4-6 weeks after injury to allow for Wallerian degeneration to occur
- stimulation done at Erb's point and recording done over cortex with scalp electrodes (transcranial)
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| Treatment |
- Nonoperative
- observation alone waiting for recovery
- indications
- most managed with closed observation
- guns shot wounds (in absence of major vascular damage can observe for three months)
- signs of neurologic recovery
- advancing Tinel sign is best clinical sign of effective nerve regeneration
- Operative
- immediate surgical exploration (< 1 week)
- indications
- sharp penetrating trauma (excluding GSWs)
- iatragenic injuries
- open injuries
- progressive neurologic deficits
- expanding hematoma or vascular injury
- techniques
- nerve repair
- nerve grafting
- neurotization
- early surgical intervention (3-6 weeks)
- indicated for near total plexus involvement and with high mechanism of energy
- delayed surgical intervention (3-6 months)
- indications
- partial upper plexus involvement and low energy mechanism
- plateau in neurologic recovery
- best not to delay surgery beyond 6 months
- techniques
- usually involves tendon/muscle transfers to restore function
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| Surgical Techniques |
- Direct nerve repair
- rarely possible due to traction and usually only possible for acute and sharp penetration injuries
- Nerve graft
- commonly used due to traction injuries (postganglionic)
- preferable to graft lesions of upper and middle trunk
- allows better chance of reinnervation of proximal muscles before irreversible changes at motor end plate
- donor sites include sural nerve, medial brachial nerve, medial antebrachial cutaneous nerve
- vascularized nerve graft includes ulnar nerve when there is a proven C8 and T1 avulsion (mobilized on superior ulnar collateral artery)
- Neurotization (nerve transfer)
- transfer working but less important motor nerve to a nonfunctioning more important denervated muscle
- use extraplexal source of axons
- spinal accessory nerve (CN XI)
- intercostal nerves
- contralateral C7
- hypoglossal nerve (CN XII)
- intraplexal nerves
- phrenic nerve
- portion of median or ulnar nerves
- pectoral nerve
- Oberlin transfer
- ulnar nerve used for upper trunk injury for biceps function
- Muscle or tendon transfer
- indications
- isolated C8-T1 injury in adult (reinervation unlikely due to distance between injury site and hand intrinsic muscles)
- priorities of repair/reconstruction
- elbow flexion (musculocutaneous nerve)
- shoulder stability (suprascapular nerve)
- brachial-thoracic pinch (pectoral nerve)
- C6-C7 sensory (lateral cord)
- wrist extension / finger flexion (lateral and posterior cords)
- wrist flexion / finger extension
- intrinsic function
- technique
- gracilis most common free muscle transfer
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