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Periphiral nerve injuries of the upper limbPrepared by: Dr. Abdullah K. Ghafour 3rd year IBFMS trainee

Supervised by:Dr. Hamid Ahmed Jaff

INTRODUCTIONPeripheral nerve damage affecting the upper extremities can vary widely in cause and extent. Many disorders, ranging from mild carpal tunnel syndrome to severe brachial plexopathy, need to be considered in a patient presenting with pain, sensory loss, or weakness involving the shoulder, arm, or hand.

ANATOMYNerve roots emerge from the spinal cord formed by ventral (anterior rami) of cervical spinal nerves C5-C8 and thoracic spinal nerves T1 form brachial plexus.Brachial plexus is responsible for cutaneous (sensory) and muscular (motor) innervation of the entire upper limb.

ANATOMY5 main nerves arise from brachial plexus:

Axillary nerve (C5,C6)Musculocutaneous nerve (C5,C6,C7)Radial nerve (C5,C6,,C7,C8 &T1)Median nerve (C5,C6,,C7,C8 &T1)Ulnar nerve (C8 &T1)

Brachial Plexus

PATHOLOGYNerves can be injured by ischaemia, compression, traction, laceration or burning.

Damage varies in severity from transient and quickly recoverable loss of function to complete interruption and degeneration.

There may be a mixture of types of damage in the various fascicles of a single nerve trunk.

Classification of Nerve InjuriesSeddons classification (1942) :Neurapraxia; mechanical pressure causing segmental demyelinationAxonotmesis; axonal interruption with loss of conduction but the nerve is in continuity and the neural tubes are intact.Neurotmesis; division of the nerve trunk with loss of continuity.

Brains classification (1943) :Localised degeneration of the myelin sheathsComplete interruption of axons with Preservation of supporting structures (Schwann tubes, endoneurium, perineurium)All essential parts destroyed, Interruption can occur without apparent loss of continuity

Classification of Nerve InjuriesIII. Sunderland classification (1978):

First degree injury; This embraces transient ischaemia and neurapraxiaSecond degree injury; axonal distruption (Axonotmesis)Third degree injury; The endoneurium is disrupted but the perineurial sheaths are intact and internal damage is limited.Fourth degree injury Only the epineurium is intact.Fifth degree injury The nerve is divided.

Diagnosis- historyHistory Which nerve ? What level ?What is the cause ? What degree of injury ? Old or fresh injury ?

Diagnosis- examinationMotor: All muscles distal to the injury paralyzed & atonic Atrophy : 50 -70 % in 1st two months Striations & motor end plate configurations retained for 12 18 months (critical limit of delay)Sensory loss usually follows a definite anatomical pattern, although factor of overlap from adjacent nerves may be presentAutonomous zoneWeber 2 point discrimination testTinels sign

Diagnosis- examinationReflex ;Abolishes all reflexes transmitted by that nerve, either afferent or efferent arc.Complete & incomplete lesion. So , not a reliable guide to injury severity.Autonomic : Loss of sweatingLoss of pilomotor responseVasomotor paralysis in autonomous zoneOthers:Trophic Changes Esp. hand and feetSkin thin, glistening, breaks easily to form ulcers Fingernails Ridged, distorted and brittle Osteoporosis (Reflex sympathetic dystrophy)

Diagnosis- examination

Brachial plexus injuryIn upper plexus injuries (C5 and 6) the shoulder abductors and external rotators and the forearm supinators are paralyzed. Sensory loss involves the outer aspect of the arm and forearm.

Erb-Duchenne palsy: (Waiters tip position)The limb hangs by the side adducted and medially rotated by unopposed pectoralis major. The forearm extended and pronated because the action of biceps is lost.

Brachial plexus injuryPure lower plexus injuries; (klumpke pulsy) are rare. Affects T1 nerve root. Wrist and finger flexors are weak and the intrinsic hand muscles are paralysed. Sensation is lost in the ulnar forearm and hand.

If the entire plexus is damaged, the whole limb is paralysed and numb.

Musculocutaneous nerve injurySENSORY SUPPLYskin oflateral forearm

MOTOR SUPPLYanteriorcompartment of arm (BBC)biceps flexes elbow, supinates forearmbrachialis flexes elbowcoracobrachialis flexes and adducts the arm at the glenohumeral joint

COMMON INJURIESmusculocutaneous nerve injuries arerare, as thenerve is protectedbeneath the bulk of the biceps muscleit may be damaged bystab woundsto theupper arm

MCN injury manifestationsSENSORY LOSSnumbness over lateral forearm

MOTOR DEFICITparalysis ofanterior compartment of arm very weakelbow flexionand weakforearmsupinationabsentbiceps reflex

DEFORMITYwastingofanterior compartment of armelbow usually held in extensionwithforearm pronated

Axillary nerve injurySensory function: sensation of an oval shaped area over the lateral shoulder sergeant's patch

Motor function: it innervates the deltoid (shoulder abduction) and teres minor (shoulder external rotation) muscles.

Common causes of injury: Trauma, usually with shoulder dislocation or humeral fracture, iatrogenic

Axillary nerve injury manifestationsSensory loss: sharply-defined region of sensory loss over the lateral shoulder sergeant's patch

Motor loss: The patient complains of shoulder weakness. Although abduction can be initiated (by supraspinatus), it cannot be maintained.

Deformity: wasting of the deltoid

Radial nerve injurySensory function: posterior arm and forearm , lateral of dorsum of hand and proximal dorsal aspect of lateral 3 fingers

Motor function: posterior compartment of the arm and forearm

Common causes of injury: fractures of proximal humerus, shaft of humerus orradius, stab wounds to antecubital fossa, forearm or wrist

Radial nerve injury manifestationsLow lesions; The patient complains of clumsiness and, on testing, cannot extend the MCP joints of the hand. In the thumb there is also weakness of extension. Wrist extension is preserved.High lesions; There is an obvious wrist drop, due to weakness of the radial extensors of the wrist, as well as inability to extend the MCP joints or elevate the thumb. Sensory loss is limited to a small patch on the dorsum around the anatomical snuffbox.Very high lesions; In addition to weakness of the wrist and hand, the triceps is paralysed and the triceps reflex is absent.

Median nerve injurySensory function: Skin over thenar eminence, lateral palm of hand and palmar aspect of lateral 3 fingers

Motor function: all muscles of anterior compartment of forearm except flexor carpi ulnaris and the medial two parts of flexor digitorum profundus

Common causes of injury: supracondylar fractures of humerus , compression by carpal tunnel syndrome

Median nerve injury manifestationsLow lesions; The patient is unable to abduct the thumb, and sensation is lost over the radial three and a half digits. In longstanding cases the thenar eminence is wasted and trophic changes may be seen.

High lesions; in addition, the long flexors to the thumb, index and middle fingers, the radial wrist flexors and the forearm pronator muscles are all paralysed pointing sign.

Ulnar nerve injurySensory function: skin over hypothenar eminence, medial palm of hand ,palmar aspect of lateral 1 fingers

Motor function: two muscles of anterior compartment of forearm , and most of the intrinsic muscles of the hand

Common causes of injury: supracondylar fractures of humerus , compression cubital tunnel in the elbow.

Ulnar nerve injury manifestationsLow lesions; There is numbness of the ulnar one and a half fingers. The hand assumes claw hand deformity with hyperextension of the MCP joints of the ring and little fingers, due to weakness of the intrinsic muscles. Finger abduction is weak and this, together with the loss of thumb adduction, makes pinch difficult.

High lesions; The hand is not markedly deformed because the ulnar half of flexor digitorum profundus is paralysed and the fingers are therefore less clawed (the high ulnar paradox). Otherwise, motor and sensory loss are the same as in low lesions.

TreatmentNonoperativeobservation with sequential EMGindicationsneuropraxia (1st degree)axonotmesis (2nd degree)Operativesurgical repairindicationsneurotomesis (3rd degree)nerve graftingindicationsdefects > 2.5 cmtype of autograft (sural, saphenous, lateral antebrachial, etc)no effect on functional recovery

TreatmentIndications for surgery:

When a sharp injury has obviously divided a nerve.When abrading, avulsing or blast wounds have rendered the condition of nerve unknown.When a nerve deficit follows a blunt or closed trauma & no clinical or electrical evidence of regeneration has occurred after an appropriate time.When a nerve deficit follows a penetrating wound as stab or low velocity gunshot wound, part observed for evidence of nerve regeneration for appropriate time.

TreatmentTypes of Nerve Repair :

EndoneurolysisPartial NeurorrhaphyNeurorrhaphy Epineural Epi-perineural PerineuralNerve grafting

TreatmentTime of Surgery:

Primary repair : First 6 8 hoursDelayed primary repair : First 7 18 daysSecondary repair : > 3 weeks

TreatmentFactors that influence regeneration after neurorrhaphy:

1. Age of patient 2. Gap between nerve ends 3. Delay between time of injury and repair 4. Level of injury 5. Condition of nerve ends 6. Experience & technique of surgeon

THANKS

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