|
http://upload.orthobullets.com/topic/1008/images/clinical image 2.jpg
http://upload.orthobullets.com/topic/1008/images/brachial plexus dissection.jpg
http://upload.orthobullets.com/topic/1008/images/bp.jpg
http://upload.orthobullets.com/topic/1008/images/brachial plexus fixed..jpg
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 topic
      • Erb's palsy
      • Klumpke palsy 
    • burners and stingers topic
    • Parsonage-Turner Syndrome topic
  • 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)
      • 83% of traumatic BPIs
    • 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
      • not repairable
    • other surgeries such as arthrodesis and tendon transfers may be needed
Anatomy
  • Anatomy
    • brachial plexus motor and sensory innervation     
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 intact
        • 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
  • Classification based on location
Upper Lesion: Erb's Palsy (C5,6) 
Introduction
Physical Exam
  • 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
  • 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)
Lower Lesion: Klumpke Palsy (C8,T1)
  • 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
  • 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
Total Palsy (C5-T1)
  • A form of brachial plexopathy
  • Worst prognosis
  • Leads to a flaccid arm
  • Involves both motor and sensory
 
Presentation
  • History
    • high energy injury
  • 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
Imaging
  • Radiographs
    • chest radiograph
      • recommended views
        • PA and lateral
      • 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
        • AP and lateral
      • 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
        • orthogonal 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 (T2 highlights water content present in a pseudomeningocele )
      • empty nerve root sleeves (T1 images highlight fat content nerve roots and empty sleeves)
      • cord shift away from midline (T1 highlights fat of cord)
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)
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)
        • iatrogenic 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
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
 

Please rate topic.

Average 3.8 of 62 Ratings

Questions (12)
EVIDENCE & REFERENCES (24)
VIDEOS (1)
CASES (1)
GROUPS (1)
Topic COMMENTS (41)
Private Note