Brachial Plexus Flashcards
Most common traumatic brachial plexus injuries are:
supraclavicular injuries involving complete involvement of all roots (80%)
Speed of nerve regeneration is:
1mm per day.
Plexus recovery can take up to 3 years
Worst prognosis is with these injuries:
root avulsions (pre-ganglionic) - not reparable
Best prognosis with these injuries
Infraclavicular plexus injuries
Upper plexus injuries (preserves hand function)
Signs of Pre-ganglionic Injury
- Horner’s syndrome
- Medial scapular winging (Long thoracic n)
- flail arm
- normal histamine test
- elevated hemidiaphragm (phrenic)
- Rhomboid paralysis (dorsal scapular n)
- Cuff weakness (suprascapular n)
- Latissimus weakness
- EMG = no innervation to cervical paraspinals
Signs of post-ganglionic injury:
EMG with maintained innervation to cervical paraspinals
- abnormal histamine test… redness and wheal positive, NO FLARE
Most common brachial plexus obstetrical palsy:
Erb’s
- C5, C6
- has best prognosis
Causes of a Klumpke Palsy
C7-8 root involvement
- hyperabduction injury
- cervical rib
- lung mets in lower deep cervical lymph nodes
Clinical features of a Klumpke:
- claw hand
- unopposed wrist extensors
- loss of hand intrinsics therefore IP flexion and MP hyperextension
Essential muscles to check in brachial plexopathy:
serratus anterior
- rhomboids (if functioning, then likely a post-ganglioinc)
Define: SNAPs
sensory nerve action potentials
- measured in NCS
- preserved in lesions proximal to the DRG. Therefore distinguishes between pre and post-ganglionic
Best clinical sign of nerve regeneration?
advancing Tinel sign
Indication for immediate surgical exploration?
sharp, penetrating trauma
- iatrogenic injuries
- open injuries
- progressive defects
- expanding hematoma or vascular injury
IS direct nerve repair possible for plexus injuries?
typically not as these are avulsion injuries
Nerve grafting plexus injuries:
- useful in traction injuries
- preferable to graft the upper and middle trunk
Neurotization for plexus injuries:
- transfer a working but non-essential motor nerve
- use extra-plexal source of axons such as CN XI, intercostal nerves, contra-lateral C7, CN XII
Oberlin Transfer:
ulnar nerve is used for upper trunk injury to gain biceps function
Horner’s Syndrome
disruption of the sympathetic chain at C8 or T1 root level
- seen concomitantly with pre-ganglionic injuries at this level
Phrenic Nerve
C3,4,5
Neurotization to restore elbow flexion - what procedure?
ulnar nerve fascicle to biceps
AND
median nerve fascicle to the brachialis
Best surgical management of late-presenting plexopathies? (liek 2 years out…)
free muscle transfers
- nerve transfers unlikely to be sufficient due to loss of neuromuscular endplates at that time frame
Quadrilateral space syndrome
dominant shoulder in overhead throwing athlete
- axillary nerve compression
- atrophy of deltoid and teres minor
Risks for obstetrical brachial plexopathy
- LGA
- multiparous
- dystocia
- forceps
- breech
- prolonged labor
Upper extremity issues from obstetrical brachial plexopathy
- glenoid dysplasia, retroversion, humeral head flattening, posterior humeral head subluxation
- Elbow flexion contracture
Poor prognosis for recovery of obstetical plexopathy?
- lack of biceps function by 3 months
- preganglionic injuries
Narakas Classification
I: Erb’s
II: Intermediate (C5-7)
III: total palsy without Horner’s
IV: total palsy with Horner’s
Elbow contracture of <40 degrees, treatment
serial extension splinting
casting if >40 deg
if recalcitrant to treatment, use surgery
How do you influence the natural history of glenoid dysplasia in obstetrical brachial plexopathy?
- address GH internal rotation contracture wth latissimus and teres major transfer
- ifdone at young age, significant remodeling potential exists
- relative contraindications include severe dysplasia such as glenoid convexity or absence, humeral head flattening
Waters Classification - significance
if Waters GH dysplasia types II or III, do latissimus/teres major transfer
if Waters IV or V, do humeral derotational osteotomy
When do you do reconstruction for post-ganglionic injuries?
at 3-9 months of life, using neuroma excision and sural nerve grafting
When do you reconstruct pre-ganglionic injuries?
at 3 months of life, using nerve transfers
What’s the prognostic value of a Horner’s syndrome in context of brachial plexopathy?
poor prognosis.
<10% will regain function (al-Qattan 2000, Waters 1999)
