BRACHIAL PLEXUS INJURY

By :Dr.K.Vivek

BRACHIAL PLEXUS LESIONS - ETIOLOGY

CLOSED 1. traction lesions 2. radiation induced

3. neoplastic

4. post operative

OPEN 1. gun shot wound lacerations

2. during surgeries

3. orthopedic related

4. needles and cannulas

• MC cause in large series is motor cycle accidents of 70%.

• In 20% cases a/w rupture of subclavian or axillary artery.

CLASSIFICATION OF BRACHIAL PLEXUS INJURIES:

• Upper Plexus Injuries(Erb's Palsy)• Lower Plexus Injuries(Klumpke)

• Leffert classified injuries acc to mech & level of injury

• Preganglionic or supraganglionic injuries occuring proximal to neural foramen in which neurons have been seperated from spinal cord.

• Postganglionic or infraganglionic injuries occur distal to neural foramen & neurons remain connected to spinal cord.

Indications for avulsion injuries and poor prognosis for recovery

● Finding1. Denervation of

paraspinal muscles2. Denervation of

rhombhoid muscles3. Scapular winging4. Horner’s syndrome5. Absent Tinel’s sign6. Sensory impairment

neck7. Hemidiaphragmatic

paralysis8. Cervical transverse

process fracture9. Pseudomeningocele10. Anesthesia and intact

conduction velocity

● Implication1. Dorsal ramii injury2. Dorsal scapular C5 injruy3. Long thoracic C5, C7 and C8

injuries4. Cervico thoracic sympathetic

injury5. Preganglionic seperation from

cord6. Cervical plexus injury7. Phrenic nerve injury8. Avulsion fracture with root

injury9. Dura and arachnoid avulsion

injury10. Dorsal ganglion intact but

avulsion from cord

TRUNK

• Upper trunk( Erbs palsy) c5,c6• Middle trunk c7• Lower trunk( Klumpke paralysis)C8,T1

Upper Brachial Plexus Injuries• Increase in angle between

neck & shoulder• Traction (stretching or

avulsion) of upper rootlets (e.g., C5,C6)

• Produces Erb’s PalsyLower Brachial Plexus Injuries• Excessive upward pull of

limb• Traction (stretching or

avulsion) oflowerrootlets (e.g., C8,

T1)• Produces Klumpke’s

Palsy

Lower brachial plexus injuries

Upper brachial plexus injuries

Erb’s Palsy (C5-C6)

General Comments Physical ExamMost common obstetric plexopathy

Clinically, arm will be adducted, internally rotated at shoulder, pronated, extended at elbow (“waiter’s tip position”)

Results from excessive displacement of head to opposite side & depression of shoulder on same side producing traction on plexus

C5 Deficiency-Axillary nerve def. (weakness in deltoid, teres minor)-Suprascapular nerve def. (weakness in supraspinatus, infraspinatus)-Musculocutaneous nerve def. (to biceps and brachialis)

Occurs during difficult delivery in infants or falls onto shoulder in adults

C6 Deficiency-Radial nerve def. (weakness in brachioradilis, supinator)

Best prognosis

LATERAL CORD

1.Isolated lesion to lateral cord consists of musculocutaneous nerve palsy plus a partial median nerve deficit ( involving C5 to C7 portion )This deficit pattern is termed a musculocutaneous plus palsy

2.The classic musculocutaneous palsy causes forearm flexion weakness secondary to biceps brachii, corachobrachialis and brachialis weakness and sensory loss in the lateral forearm

3.The lateral cord provides all the median nerve’s sensory fibers. So, sensory loss in the lateral palm and first 3 digits occurs with a lateral cord injury

4.Proximal median innervated muscles(pronator teres, FCR)weakness in pronation and wrist flexion.

MEDIAL CORD1.An isolated medial cord lesion consists of an ulnar nerve palsy plus loss of C8 and T1 components of the median nerve.

2.An ulnar nerve palsy would cause weakness in wrist flexion (flexor carpi ulnaris), distal interphalangeal joint flexion weakness involving the ring and little fingers (flexor digitorum profundii ), little finger movements ( opponens, flexor and abductor digiti minimi ), and finger abduction and adduction ( interossei ).

3.Medial cord sensory loss involves the medial 1/3rd of the hand

4.Medial cord lesion or ulnar plus palsy would in addition to causing ulnar motor loss, cause median innervated thumb weakness(opponens pollicis,flexor pollicis brevis,abductor,) and trouble extending the proximal interphalangeal joints of the 1st two fingers (lumbricals).

5.Medial pectoral nerve from proximal medial cord, if damaged leads to weakness in the sternal head of the pectoralis major.

POSTERIOR CORD

1.Combination palsy of radial and axillary nerve is the hallmark of posterior cord injury.Also called radial axillary palsy.

2.Radial palsy causes weakness in forearm extension (triceps), forearm supination (supinator), wrist extension ( extensor carpi radialis longus and brevis, extensor carpi ulnaris ), and finger/thumb extension ( superficial and deep finger extensors )

3.Radial nerve sensory loss involves the posterior arm and forearm, the lower lateral aspect of arm and lateral dorsal hand.

4.An axillary nerve palsy causes arm abduction weakness secondary to deltoid paralysis.

5.An axillary nerve lesion can also cause sensory loss in the upper lateral arm

Plain RadiographsPlain X ray film Findings Significance

Chest Elevated hemidiaphragm Phrenic injury, proximal plexus, and possible preganglionic avulsion

First rib fracture Subclavian or axillary artery injury – Lower trunk injury

C – spine Fracture or dislocation Cervical spine injury

Transverse process # Preganglionic avulsion injury

Clavicle Fracture Possible traction injury to plexus or pseudoparalysis

Shoulder Glenohumeral dislocation Infraclavicular injury

Scapulothoracic dislocation Severe neurovascular injury

Imaging study

1.C T Myelography or MRI may show pseudomeningoceles produced by root avulsion(6 to 12 weeks recommended ).

2.Note that during the first few days a ‘positive’ result is unreliable because the dura can be torn without there being root avulsion.

3.MRI shoes pseudo meningocele or complete absence of root shadows at the level of avulsion (inaccurate early after injury bcoz clotted blood may occlude pseudo meningocele)

4.MRI for pt with traction injury to the brachial plexus

TINEL SIGN

1.Percussion by finger Transient tingling sensation Distal to proximal direction

2.Indicate regenerating axonal sprouts that have not obtained complete myelinization are progressing along the neural tube

Elicited by placing a drop of histamine on the skin along the distribution of the nerve being examined

Skin scratched through the drop of histamine : cutaneous vasodilation, wheal formation, and flare response

Nerve interrupted proximal to the ganglion:anesthesia along its cutaneous course, normalaxon response Injury is distal to the ganglion : anesthesia along

the course of the nerve, and vasodilation and wheal formation seen, flare response absent

Sweat test

Sympathetic fibres within a peripheral nerve are resistant to mechanical trauma

Autonomous zone – presence of sweating –no complete interruption of nerve Iodine starch test- quinizarin powder

Denervated area—dry and light gray

Normal area – purple colour

Studies-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

NERVE CONDUCTION STUDY-electrical stimulate-it should be done after 10 days

-Nerve conduction studies need careful interpretation. If there is sensory conduction(sensory nerve action potentials) from an anaesthetic dermatome.

- This suggests a preganglionic lesion

-This test becomes reliable only after a few weeks, when wallerian degeneration in a postganglionic lesion will block nerve conduction

ELECTROMYOGRAPHYAfter 10 to 14 days of neural injury,abnormal spontaneous rest potentials evolve(positive sharp waves)b/w 14 to 18 days fibrillation appear.Abnormal spontaneous rest potentials may last indefinitely until the muscle has become reinnervated or fibrotic3 months of injury peripheral neural sprouting occur and the motor unit potential amplitute progressively increasesb/w 2 to 6 months larger than normal appearing potential .

SKIN RESISTANCE TEST

-Richter dermometer -Denervated area– increased resistance to electrical currentInnervated area – normal resistance-Galvanic stimulation: chronaxy and strength duration curve

MANAGEMENT

• Closed Brachial Plexus Injury• Open Brachial Plexus Injury

Closed Brachial Plexus Injury• Barnes divided Upper & Lower

Plexuses injuries caused by traction into four groups

• 1)Injuries at C5 & C6(spontaneous recovery)

• 2)Injuries at C5,C6 & C7• 3)Degenerative lesions of entire

plexus(partial recovery)• 4)Injuries at C7,C8 & T1 (rare)

Open Brachial Plexus Injury

• Indications for Surgery:• Injuries caused by sharp objects

or missiles.• Injuries to adjacent vessels or

mediastinal, thoracic viscera must be treated first

• When pt not seen soon after injury but only after initial management,

• It is best to wait for wound healing & stabilization of any other injuries.

• During this period locate neurological deficit for level of injury.

• EMG performed 3 to 4 wks after injury.

• Exploration of plexus & neurorrhaphy, autogenous interfascicular nerve grafting or neurolysis is indicated 3 to 6wks after injury.

SURGICAL GOALS

In order of priority as follows:

-Restoration of elbow flexion

- Restoration of shoulder abduction

-Restoration of sensation of medial

borderof forearm & hand(neurovascular island

graft).

Important Nerves for Upper Brachial

Plexus Injury & ReconstructionNerve Muscles

innervatedFunction

Musculocutaneous Biceps & Brachialis Elbow flexionAxillary Deltoid Shoulder abductionSuprascapular Supraspinatus Shoulder abduction

and stabilityMedian Wrist & Finger

Flexion, Radial Hand Sensation

Wrist & Finger Flexion, Hand Sensation

Ulnar Wrist & Finger Flexion, Ulnar Hand Sensation

Wrist & Finger Flexion, Ulnar Hand Sensation

Neurolysis Nerve repair NeurorraphyNerve GraftNerve TransferFunctional muscle transfer

•

- Effective only if scar tissue seen around nerve or inside epineurium, preventing recovery or causing pain

-External neurolysis

-Internal neurolysis

NEURORRHAPHY

-Epineural

-Perineural

-Interfascicular

METHODS OF CLOSING GAP

-Mobilization-Positioning of extremity-Transposition-Bone resection-Nerve grafting-Nerve allograft-Synthetic nerve conduits

Surgical Techniques-Nervegraft

• Commonly used due to traction injuries (postganglionic).

• Preferable to graft lesions of upper and middle trunk

• Donor sites include sural nerve, medial brachial nerve, medial antebrachial cutaneous nerve

Nerve repairs performed with fibrin sealants produced less inflammatory response and fibrosis, better axonal regeneration, and better fiber alignment than the nerve repairs performed with microsutures alone.

Act as a temporary scaffold across which axons regenerate

Ultimately, the allograft tissue completely replaced with host material

Tacrolimus, greater potential and fewer side effects than other

immunosuppressants, neuroregenerative and neuroprotective effects

Help in directing axonal sprouts from the proximal stump to the distal nerve stump

Provide a channel for diffusion of neurotropic and neurotrophic factors and minimize infiltration of fibrous tissue

Silicone,polygalactin,poly L lactic acid,poly glycolic acid,polyvinyl alcohol

Surgical Techniques-Neurotization

(Nerve Transfers)• 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

Nerve Transfer Options (Upper Plexus

Injured Nerve

Nerve Transfer Function Restored

Musculocutaneous

Median and Ulnar (FCU)fascicles/ICN

Elbow flexion

Axillary Radial fascicles Shoulder Stability & abduction

Suprascapular Spinal accessory (XI) fascicles

Shoulder Stability & abduction

After brachial plexus repair & regeneration 12 to 18 mths required to determine extent

of neural regeneration.

If recovery inadequate Peripheral

reconstruction considered

tendon transfer about the elbowBUNNEL AND CAROLL PROCEDURE

Anterior transfer of the triceps tendon

FLEXORPLASTY(steindler)Indications: -biceps and brachialis paralysed -detach the common flexor group muscles ---advance 5 cm lateral side rather than medial side of humerus

TRANSFER OF PECTORALIS MAJOR TENDON

BROOK AND SEDDON To restore the elbow flexion in which pectrolis major muscle is used as motor and its tendon is prolonged distally by means of long head of biceps.

• To improve shoulder ABDUCTIONand EXTERNAL ROTATION• Tendon transfer around shoulder

considered include TRAPEZIUS TO DELTOID transfer

• For abduction LATISMUS DORSI & TERES MAJOR transfer as described

by L'Episcopo FOR ER of shoulder jt.

BATEMAN PROCEDURE Trapezius insertion freed by resecting the lateral clavicle, acromion,adjoining part of scapular spine are anchored to the humerus by screws

SHOULDER ARTHRODESIS

●If active scapulothoracic motion is preserved

●To improve elbow flexion by preventing uncontrolled IR of shoulder

●Shoulder fused in 20 to 30 degrees of abduction