Brachial Plexus Injuries & Reconstruction Flashcards
Where do the roots, truncks, cords, divisions and terminal branches lie and what are their contributions
- 5 Roots - C5-T1 (C8 and T1 exit from above named formina)
- located betwene anterior and middle scalene
- prefixed C4
- post fixed T2
- 3 Truncks - Upper (C5-C6), Middle (C7), Lower (C8-T1)
- located in posterior triangle
- 6 Divisions - Anterior and Posterior division of each
- located posterior to clavicle
- 3 Cords (Lateral, Medial, Posterior) in relation to axillary artery
- located posterior to pectoralis minor
- 5 Terminal branches (Rad, Ax, Uln, Med, MSC)
- located in limb
CORDS
what forms and what is formed by each cord
- LATERAL CORD
- made up of C5-7 (anterior division of upper and middle trunks)
- forms Lateral pectoral (ant division upper and middle T)
- forms MSC (anterior division of upper and middle T)
- forms lateral contributing branch of median nerve => contributes to sensation
- MEDIAL CORD
- made up of C5-T1 (anterior division of Lower trunk + gets lateral contributing branch to median nerve)
- forms medial pectoral nerve, MABC, MBC
- forms medial contributing branchof median nerve => contributes to intrinsics fx
- POSTERIOR CORD
- made up of C5-T1 (posterior division of all trunks)
- forms upper, lower subscapular n and Td
- forms Radia and Axilary branches
What nerves arises proximal to the cords on the brachial plexus?
- Dorsal scapular nerve (C5 root)
- Phernic nerve (C3,4,5 roots)
- Long thoracic nerve (C5,6,7 roots)
- Suprascapular nerve (upper trunk = C5,6)???
- Lateral pectoral nerve (upper ttrunk anterior div = C5,6)???
- Subclavius (upper trunk C5,6)
- Paraspinal muscle nerves (longus colli, scalene muscles C5,6,7,8)
- 1st intercostal (T1 root)
What is the incidence of OBPP
1-2/1000
How do you classify BP injuries
Pathology
- root avulsion
- nerve rupture
- NIC
Location
- preganglionic (~root avulsion)
- postganglionic( ~nerve rupture)
What is important points on Hx and PE for BP injury assessment
Hx
- mechanism, arm position when injured
- associated injuries (spine/head/limbs/chest)
- weakness/paresthesia
- improvement with time (delayed assessment)
- LOC/lifethreatening injuries (acute assessment)
PE
- ABC, general exam if acute
- peripheral pulse
- BP exam - according to MRC grading
- root avulsion
- horners (C8,T1 avulsion or traction near)
- head deviated away from injured side (weak paraspinals)
- winging scapula and difficulty raising arm above horixontal ( weak serratus ant)
- winging scapula and cannot be drawn close to vertebral column (weak rhomboids/levator scap)
- subluxed humerus + inability to lift above horizontal (Supraspinatus)
- tally functional and non-functional
- root avulsion
- BP exam sensation
- light touch, 2PD static dynamic, vibration, joint position
- root avulsion
- painful limb
- intact histamine response in anesthestic arm
- intact SSEP in anesthetic arm
Spot diagnosis
Spontaneous recovery following diffuse BP injury with weak/slowly recovery arm abduction/external rotation
compression of SSN in Scapular Notch
May require release
What nerve injury would you suspect with posterior shoulder dislocation
axillary nerve rupture
Contrast findings for preganglionic vs postganglionic BP injuries
- On inspection
- flail arm for both
- head direcetd away from injury in preGG
- winging scapula preGG
- horners preGG
- On palpation and muscle testing
- paralysis of limb for both
- paralysis of diaphragm, serratus, rhomboids preGG
- On palpation and sensory testing
- paresthesia in both
- intact histamine response in preGG
- deafferentiation PAIN in preGG
- Tinels ABSENT preGG
- On investigation
- pseudomeningocele in myelogram preGG
- NCS: absent motor EP for both
- sensory EP in postGG
- ABSENT SENSORY EP in preGG
- EMG: denervation limb for both
- paraspinal denervation preGG
What investigations would you order for BP assessment, when and why?
- On initial assessment
- Chest X-ray - Fractured cpsine, clavicle, ribs, humerus/shoulder girdle
- Ins/Exp CXR - diaphragm injury (or U/S)
- Arteriogram
- penetrating injury
- normal initial exam then abnormal exam (R/O expanding hematoma)
- 4weeks post trauma
- CT/Myelogram
- to assess root avulsion - traumatic pseudomeningocele correlates w avulsion
- CT/Myelogram
- >3wks post trauma
- ElectoDiagnostic studies:
- EMG
- identify denervation injury
- fibrillation ant rest
- reduced MUP with voluntary effort
- identify denervation injury
- NCS
- identify interruptions in nerve continuity and level of injury
- postive SNAP in paresthetic arm = pathognomoni for root avulsion
*
What are treatment options for BP injuries
- Non-operative
- PT to maintain ROM/joint mobility
- treat fractures with immobilization
- Operative management
- neurolysis
- autogenous nerve grating
- nerve transfers
- secondary procedures (NT, TT, osteotomies)
What are principles for deciding on operative management for BP injuries
- Outcomes are better with spontaneous recovery compared to operative Tx
- Patients who require operative Tx have better outcomes if done earlier
- Patients with SUnderland 4-5 injuries benefit from operative intervention, not sunderland 1-2
- Patients w sunderland 3 recvere with some partial deficits with can be corrected w 2’ procedures
what are indications for operative intervention for BP injury
- Penetrating injury with BP deficits
- clear indication of injury to Roots
- lack of functional recovery after period of observation
What are contraindications to primary reconstruction of BP injury
ABSOLUTE
- Medically unfit
- demonstrates spontaneous recovery
RELATIVE
- comorbidities, TBI, SCI
- over 1yr since injury in adults
How do you prioritize reconstruction of total branchial pleoxpathy
Based on principles of
- function significance
- likelihood of regained fx w operation
- degree of difficulty achieving function w 2’ surgery
Order of reconstruction
- Elbow Flexion
- Shoulder stabilization (abdunction,external rotation, flexion)
- Sensation to C5,6 (lateral cord)
- Wrist and finger flexion (with consideration of Triceps extension if planning FFMT for elbow)
- Wrist and finger extension
- Intrinsics
How do you provide shoulder stability and goals of recon
- stabilize shoulder to prevent pain of subluxation and for platform to properly tuilize elbow flexion
- reinnervate Supraspinatus (abduction) and Infraspinatus (external rotation) with SA to SSN
- reinnervate Deltoid (abduction/flexion) via triceps br to Axllary
How do you manage Open BP injuries?
OPEN AND EXPLORE
- Sharp laceration
- => 1’ epineurial repair
- => vascular repair with vein grafts in conjunction b/w vascualr and plastic Sx
- Crush/nerve loss
- => identify, tag and map out injury
- return in 3wks (following completion of any WD likely to occur) for grafting as required
- Gunshot
- expected sunderland 1,2 and 3 injuries
- most improve in 3mths
- EARLY EXPLORATION ONLY if associated vascular injury
- observe 4 mths - if no evidence on PE or EDS of improvement, explore
What is the difference between SS Evoked potential/ Motor Evoked potential and Nerve Actional potential?
- EP determine continuity across Scord and peripheral nerve
- AP determine contuity across nerve segment
What are intraoperative adjuncts unsed for BP recon and why?
- AP and EP to determine continutiy across nerve segment (AP) and continuity form Scord to peripheral nerve (EP)
- Biopsies/frozen sections to determine healthy axon ends for grafting, and distinguishing ganglions cells (avulsion injury) and scar tissue
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What histochemical stians are used on proximal stump to distinguish sensory from motor?
- Sensory: Carbonic anhydrase
- Motor: Thiocoline (cholinesterase enzyme)
- Motor: Choline Acetyl trasnferase activity
**can only stain distal stump up to 5 days post injury
What are options for surgical management of BP injuries
- 1’ neurorrhaphy
- Indicated: sharp trasnsection (rare)
- Indicated: nerve rupture and no tension
- neurolysis
- Indicated - Neuroma with intact NAP
- external (epineurium fro surrounding)
- internal (perineural - along fascicles
- Nerve grafting
- Indicated - Neuroma with no NAP
- NIC w no NAP=>excision and grafting
- INdicated: Nerve rupture
- Nerve transfer
- Indicated - root avulsion
What are options for autogenous nerve grafts
- Non-vascularized
- Sural (3-40cm)
- Supraclvicula rn from cervical plexus
- MABC, LABC, MBC
- DSRn
- Vascularized
- ulnar n
- radial n
- sural n
What are indications for nerve transfers
- Irreparable PreGG
- Select PostGG
- insufficient proximal stump
- prohibitively long distance for reinnervation
- undefined level of nerve injury
- prohibitively difficult surgery in zone of injury
- BP neuritis
- Reinnervation of FFMT
What are 3 principles of nerve trasnfer
- select donor nerve close to end organ
- select expandable donor nerve
- select donot nerve w synergy/easy to relearn
Shoulder stabilization:
- SAN to SSN and Medial Triceps to Axillary
Why is posterior approach favored over anterior approach
- preserve proximal fibers of SAN to upper muscle fibers of Trapezius and divide DONOR as DISTAL as possible
- release scapular notch
- dissect Axillary N proximally to include fibers and reinnervate Teres minor (external rotation) and divide RECIPIENT as PROXIMAL as possible
- Get donor trasnferring nerve as close to end organ as possible
What are the anatomic landmarks for SAN
40% the distance from midline to acromion, along superior border of scapula
Nerve runs on undersurface of trapezius
What is the anaotmic landmark of the SSN
50% the distance between the acromion and the superomedial edge of the scapula
At this point, the SSN is in Scapular notch
What is the oberlin trasnfer and the double fascicular trasnfer
- Oberlin trasnfer: nerve trasnfer of ulnar nerve motor fascicles from FCU to biceps branch for elbow function (MSC origin)
- ulnar nerve br is carefully selected by stimulation to ensure donot flexes wrist and is not involved in intrinsics
- Double Fascicular trasnfer = Oberlin’s trasnfer + median nerve fascicle from FCR/PL transferred to Brachialis
Whata re the arguments for and against contralat C7 donor for panplexopathy
- C7 nerve trasnfer using vascularized ulnar n to reinnervation shoulder, elbow, hand contralaterally
- Argument for:
- large donor with many axons avialable for reinnervation of many targets
- no permanent functional deficit in donor arm (get transient motor weakness and paresthesia in C7 dermatome which resolves in 6mths
- Argument against:
- risk neuropathic pain, permant sensory/motor deficit
- difficult to activate recipient without activating donor limb
- long distance for reinnervation
What nerve trasnfers are performed for restoration of sensation?
Depends on whether partial (1stage) or complete plexopathy (need 2stages)
- Partial plexopathy - use web space donor of non-critical to restore critical.
- eg. upper trunk plexopathy => use ulnar nerve donor 4th Webspace CDN to trasnfer to 1st webspce for median nerve
- Complete plexopathy - 2 stages - restore one nerve proximally an once evidence of reinnervation , use reinnervated nerve non critical sensosry br for critical nerve restoration
- eg. total plexopathy => restor eulnar n with IC trasnfer then once reinnervtion present, do trasnfer listed above (4thWS to 1stWS)
What are options for secondary reconstruction for BP injury
- TT
- FFMT
- arthrodesis
- pedicled musle trasnfers
What are options for 2’ recon of shoulder abduction/external rotation/flexion?
- Trapezius to humerus
- Episco procedure - Lat dorsi and teres major trasnfer posterolateral on humerus
- Biceps and triceps long head advanced to acromion
- Posterior deltoid rotated anteriorly
If not possible, then arthrodesis
What are options for secondary recon of elbow flexion? (all indicated for upper trunk/MSC injury with delayed presentation or no evidence of elbow function recovery)
- Steindler modified flexorplasty
- medial epicondyle w flexor pronator mass transfered to anterolat humerus
- Triceps to biceps
- medial triceps to biceps tendon
- Pedicled muscle trasnfer
- Lat dorsi - bipolar => both origin and insertion are trasnferred. HUmeral origin to Coracoid, Tubed insertion of lat to biceps tendon
- Pec major - bipolar => origin on humerus trasnfered ot acromion, insertions with rectus abdo fascia sutured to biceps
- FFMT
- gracilis
How do you manage pain syndromes associated with BP injury
50% without root avulsions, 80% with root avulsions
- good response to nerve repair
- neurolysis, nerve grafting, neuroma excision and grafting
- PT
- pain specialist
- TENS
How do you classify obstetrical BP injuries
- Upper plexus palsy C5,6 +/- C7
- most common
- shoulder adducted, internally rotated, wrist & fingers flexed, pronated
- Lower plexus palsy C8 T1
- rare
- hand atrophy and weak wrist flexors +/- horners
What are indications surgical intervention in OBPP
- EARLY at 1-2months
- Total plexopathy with Horners and NO improvement in 1st month - operate at 2mo
- they will demonstrate no sponaneous recovery
- if evidence of some recovery at 1mth , continue to observe until 3mths
- At 3mths
- Surgery if no elbow flexion Plus No elbow/wrist/finger extension
- if score >3.5 (motion >1/2 gravity eliminated) continue to observe
- if some biceps function, continue to observe
- At 9 months
- Surgery if elbow flexion< 6 (= less than half of normal motion) -. Cookie test - elbow held adducted and child encouraged to eat cookie with less than 45’ neck flexion
- Surgery recommended at any time if reocvery stops
