Download PERIPHERAL NERVE INJURIES

PERIPHERAL NERVE
INJURIES
ALI AL-OMARI, MD
ASS. PROFESSOR
ORTHOPAEDICS AND SPINE SURGERY
FACULTY OF MEDICINE
JORDAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
Structure of a nerve
 epineural sheath:
•
surrounds peripheral nerve
 Epineurium
•
surrounds a group of fascicles to
peripheral nerve
form
•
functions to cushion fascicles against
external pressure
 Perineurium
•
connective tissue covering individual
fascicles
•
primary source of tensile
strength and elasticity of a peripheral nerve
•
•
provides extension of the blood-brain barrier
provides a connective tissue sheath around
each nerve fascicle
•Fascicles
• a group of axons and surrounding
endoneurium
•Endoneurium
• fibrous tissue covering axons
• participates in the formation of
Schwann cell tube
•Myelin
• made by Schwann cells
• functions to increase conduction
velocity
•Neuron cell
• cell body - the metabolic center
that makes up < 10% of cell mass
• axon - primary conducting vehicle
• dendrites - thin branching
processes that receive input from
surrounding nerve cells
Nerve fiber types
Fiber Type
Diameter
(uM)
Myelination
Speed
Example
A
10-20
heavy
fast
touch
B
<3
moderate
medium
ANS
C
< 1.3
none
slow
pain
Pathology of nerve injuries

1)
Mechanisms:
Ischaemia:




15 min numbness and tingling
30 min loss of pain
45 min muscle weakness
Relief of ischemia intense parasthesia for 5 min “pins and needles” sensation restored within 30
seconds muscle power after 10 mins
Stretching:
2)



8% affect microcirculation
15%  disrupt axons
Examples: Stingers, suprascapular nerve stretching, peroneal nerve after valgus correction in total knee
replacement.
Pathology of nerve injuries
3) Compression/crush:

Local deformation local ischemia increase vascular permeability endoneural
edema axon compression poor axonal transport and nerve dysfunction.

fibroblasts invade if compression persists scar impairs fascicular gliding

30 mmHg parasthesia (increase latencies)

60 mmHg complete conduction block.
4) Laceration:

Better than compression injuries

Ends retract nerve stop producing neurotransmitters nerve start to product proteins
of axon regeneration.
Pathology of nerve injuries

Regeneration after transection:

From proximal to distal
Neural sheet intact or repaired

Distal segment undergoes Wallerian degeneration (axoplasm and myelin are degraded distally by phagocytes).

Existing Schwann cells proliferate and line up on basement membrane.

Lee et al. reviewed peripheral never injury and repair. They commented that Wallerian degeneration is
initiated 48 to 96 hours after transection. The Schwann cells then align themselves longitudinally, creating
columns of cells called Büngner bands. At the tip of the regenerating axon is the growth cone.

Proximal budding (occurs after 1 month delay) leads to sprouting axons that migrate at 1mm/day to
connect to the distal tube.

Pathology of nerve injuries

1)
2)
3)
4)
Factors affect recovery:
Age (most important)
Level of injury (distal vs proximal) 2nd most important.
Mechanism of injury (sharp vs crush)
Repair timing (time limit for repair 18 months).
NOTE: PAIN IS FIRST INDICATOR TO RETURN OF FUNCTION
Radiculopathy
 Process affecting the nerve root, most commonly by a herniated disc
Weakness in muscles supplied by the nerve
root (myotome)
Sensory loss in the area of the skin supplied by
the nerve root (dermatome)
Mononeuropathy
 Dysfunction of a single peripheral nerve
Weakness in muscles supplied by the nerve
Sensory loss in the area of the skin supplied by
the cutaneous branches of the nerve
Polyneuropathy
 Symetrical dysfunction of peripheral nerves
 Sensory
 Motor
 Metabolic, DM, viral ….
Polyneuritis Multiplex
 Asymetrical involvement of several peripheral nerves
 Metabolic, viral…
Plexopathy
 Can refer to involvement of the
entire plexus, or parts of the plexus
Trunk lesion
Cord lesion
 Distribution of weakness and
numbness depends upon the part
of the plexus affected
Neuroma
Sprouting of nerve fibers
aimlessly resulting in pain and
sensitivity to touch along its
distribution
Double-crush phenomenon
 Blockage of axonal transport at one point makes the entire axon more
susceptible to compression elsewhere.
 Cervical radiculopathy or proximal nerve entrapment may coexist with
distal nerve compression in double-crush syndrome.
 Outcome of surgical decompression may be disappointing unless all points
of compression are addressed.
 Logical to start with less complex distal releases first.
Causes Of Neuropathy
Metabolic
Toxic
Viral
Compression
trauma
Classifications
Seddon classification:
 Neurapraxia
•
Mild nerve stretch or contusion
•
Focal conduction block
•
No wallerian degeneration
•
Disruption of myelin sheath
•
Epineurium, perineurium, endoneurium intact
•
Prognosis excellent, recovery expected
 Axonotmesis
•
Incomplete nerve injury
•
Focal conduction block
•
Wallerian degeneration distal to injury
•
Disruption of axons
•
Sequential loss of axon, endoneurium, perineurium (Sunderland class 2, 3, and 4)
•
May develop neuroma-in-continuity
•
Recovery unpredictable
 Neurotmesis
•
Complete nerve injury
•
Focal conduction block
•
Wallerian degeneration distal to injury
•
Disruption of all layers, including epineurium
•
Proximal nerve end forms neuroma
•
Distal end forms glioma
•
Worst prognosis
Classifications
Sunderland classification
 1st degree
 same as neurapraxia
 2nd degree
 same as axonotmesis
 3rd degree
 injury with endoneurial scarring
 most variable degree of ultimate recovery
 4th degree
 nerve in continuity but at the level of injury there is complete scarring
across the nerve)
 5th degree
 same as neurotmesis
Classifications
Classifications
Clinical features
 Nerve injuries are easily missed if associated with fractures and
dislocations.
 Always test for nerve injuries in any significant trauma, pre- and postoperation or manipulation.
 Full neurological exam (abnormal gaits, weakness in specific muscle
group, change in sensibility)
 If nerve injuries is diagnosed look for accompanying vascular injuries.
 OPEN WOUND  EARLY EXPLORATION.
Clinical features
 Level, type and degree of damage.
 Low energy neurapraxia
 High energy axonotmesis or neurotmesis.
 In doubtful case, wait and see to role out complete transection.
 Time of recovery!!!
Tinel’s sign:
• Peripheral tingling provoked by percussion the
nerve at site of injury.
• Sensitive spot progress distally in regenerating
nerve.
Clinical features
 Electrodiagnostic tests:
1)
EMG (Electromyography)
2)
NCV (LATANCIES MORE IMPORTANT THAN VELOSITY)
Principles of Localization
 Certain sites are prone to nerve entrapments/injuries
Nerve opposing bone
Ulnar nerve at the elbow
Closed spaces
Carpal tunnel
Adjacent structures
Median nerve at the elbow, adjacent to the
brachial artery
Principles of localization, cont
 Order in which branches arise
 Movements at specific joints
Single nerve
Elbow extension
Radial
Multiple nerves
Elbow flexion
Musculocutaneous
Radial
Typical deformities :
 Wrist drop ---- radial nerve injury
 Claw hand ---- ulnar nerve injury
 Foot drop ---- common peroneal nerve injury
 Ape thumb ---- median nerve injury
 Winging of scapula ---- long thoracic nerve injury
 Pointing index ---- median nerve injury
Factors Affecting Recovery
 In favor
 Younger age
 Type of injury
 More distal injury
 Time of repair: first 3 weeks
 Pure motor or sensory
Treatment
 Nonoperative
 observation with sequential EMG
 indications
 neuropraxia (1st degree)
 axonotmesis (2nd degree)
 Operative
 surgical repair
 indications
 neurotomesis (3rd degree)
Treatment
Open wound early exploration and primary repair
with 10-0 epineural repair, if large defect more than 2.5 cm despite
of mobilization autograft (sural, saphenous, lateral antebrachial, etc)
vs allograft (collagen conduits) physiotherapy.
Close wound  wait and see failure of recovery
within time frame (good care for paralyzed part and dynamic
splint) delayed repair with resection of proximal neuroma and
distal glioma.
Treatment
 Direct muscular neurotization
 insert proximal nerve stump into affected muscle belly
 results in less than normal function but is indicated in certain cases
 Epineural Repair
 primary repair of the epineurium in a tension free fashion
 first resect proximal neuroma and distal glioma
 it is critical to properly align nerve ends during repair to maximize potential
of recovery
Treatment

Fasicular repair
 indications
 three indications exist for grouped fascicular repair
 median nerve in distal third of forearm
 ulnar nerve in distal third of forearm
 sciatic nerve in thigh
 technique
 similar to epineural repair, but in addition repair the perineural sheaths (individual fascicles
are approximated under a microscope)
 outcomes
 no improved results have been demonstrated over epineural repair

Nerve grafting
 autologous graft
 remains the gold standard of repair for segmental defects > 5cm is autologous nerve
grafting
 allograft
 the only synthetic graft which shows equal results to autologous nerve grafting is a collagen
conduit
 collagen conduits allow for nutrient exchange and accessibility of neurotrophic factors to
the axonal growth zone during regeneration
COMPRESSION
NEUROPATHies OF THE
UPPER LIMB
 Entrapment neuropathy is caused by the direct pressure
on a single nerve.
 Symptoms & signs depend on which nerve is affected.
 Earliest symptoms to occur: tingling & neuropathic pain.
 Followed by reduced sensation or complete numbness
 Muscle weakness is noticed later, followed by muscle
atrophy.
Pathophysiology
COMPRESSIO
N
FIBROSIS
VENOUS
OBSTRUCTION
+ ISCHEMIA
PERSISTENT
EDEMA +
ANOXIA/
HYPOXIA
IMPAIRMENT
OF SUPPLY
DEFICIENC
Y OF VITAL
NUTRIENTS
ANOXIC
SEGMENT
CONT OF
VICIOUS
CYCLE
FUNCTIONA
L
IMPAIRMEN
T
NEURAL
EDEMA &
DILATATION
OF SMALL
VESSELS
EXACERBATION
OF ORIGINAL
COMPRESSION
PERMANENT
IMPAIRMENT
OF
FUNCTION IF
LEFT
UNTREATED
MEDIAN NERVE
 3 important compression neuropathies from distal to proximal
 CARPAL TUNNEL SYNDROME
 ANTERIOR INTEROSSEOUS SYNDROME
 PRONATOR SYNDROME
CARPAL TUNNEL SYNDROME
 Results from compression of the median nerve within the carpal
tunnel.
 Most common compression neuropathy in the upper limb.
ANATOMY
- Cylindrical cavity connecting the volar forearm with the palm.
- Floor: transverse arch of carpal bones
- Medially: hook of hamate, triquetrum & pisiform
- Laterally: scaphoid, trapezium & fibro osseous flexor carpi radialis sheath.
- Roof: proximally flexor retinaculum, transverse carpal ligament over the wrist and
aponeurosis between thenar & hypothenar muscles distally.
CONTENTS:
Tendons of flexor digitorum superficialis &
profundus in a common sheath
Tendon of flexor pollicus longus in an
independent sheath
Median nerve
ETIOLOGY:
 DECREASE IN SIZE OF CARPAL TUNNEL
 Bony abnormalities of the carpal bones
 Acromegaly
 INCREASE IN CONTENTS OF CANAL
 Forearm & wrist fractures (colle’s, scaphoid)
 Dislocations & subluxations (scaphoid rotary subluxation, lunate volar
dislocation)
 Post traumatic arthritis (osteophytes)
 Aberrant muscles (lumbricals, palmaris longus, palmaris profundus)
 Local tumours (neuroma, lipoma, ganglion, cysts, multiple myeloma)
 Persistent medial artery
 Hyrertrophic synovium
 Hematoma (hemophilia, anti coagulation therapy, trauma)
 NEUROPATHIC CONDITIONS




DM
Alcoholism
Double crush syndrome
Exposure to industrial solvents
 INFLAMMATORY CONDITIONS




Rheumatoid arthritis
Gout
Non specific tenosynovitis
Infections
 EXTERNAL FORCES
 Vibration
 Direct pressure
 ALTERATIONS OF FLUID BALANCE
 Pregnancy
 Menopause
 Eclampsia
 Thyroid disorders (esp. hypothyroidism)
 Renal failure
 Long term hemodialysis
 Raynaud’s disease
 Obesity
Clinical Features
 Paresthesias and pain (often at night) in volar aspect of radial 3½ digits
(thumb, index, long and radial half of ring)
 Large sensory fibers (light touch, vibration) are affected before small fibers
(pain and temperature)
 Pain usually wake up patient from sleep
 Weakness, loss of fine motor control, and abnormal twopoint discriminationare later findings.
 Thenar atrophy may be present in severe denervation
CLINICAL FEATURES:
 SIGNS : Tinel's sign, thenar atrophy, sensory
changes in the distribution of median nerve
 Tinel’s sign: percussing the
median nerve at the wrist.
 Phalen’s test:
 Patient places elbow on table,
forearm vertical with wrist flexed.
 Numbness & Tingling in median nerve
distribution occurs in 60 seconds in + ve cases.
 Reverse Phalen’s test:
 Sustained extension of the wrist may also
aggravate the symptoms. Not a reliable test.
 TOURNIQUET TEST:
 Inflating a BP cuff on the arm to a pressure above systolic pressure will initiate
symptoms (paraesthesia & numbness).
 DURKAN’S TEST:
 Application of direct pressure on the carpal tunnel with either pressure
manometer or by thumb of the examiner for 30 seconds will produce the
symptoms.
SENSORY TESTS
• Weber’s 2 point discrimination test:
 Test is positive in about one-third cases.
• Semmes - Weinstein monofilaments:
 Monofilaments of increasing diameters are touched to palmar side of the digit until
the patient can tell which digit is touched.
INVESTIGATIONS:

Electro diagnostic studies:
 Most reliable confirmatory test.
 Conduction time & latency for both sensory & motor conduction is determined.

CT & MRI:
If mass is suspected within the carpal tunnel

LABORATORY TESTS: specific cause is suspected
 Renal & thyroid function, RA factor, ESR, Anti nuclear antibody, uric acid, blood
sugars.
 Radiographs: Wrist AP, Lateral, Carpal tunnel views. Useful in detecting congenital
anomalies, fractures, Calcific deposits or tumours of carpal bones.
TREATMENT:
 NON OPERATIVE
 OPERATIVE
NON OPERATIVE:
 Activity modification
 NSAID’S
 Splinting
 Treating the underlying disease
 Local steroid injections
OPERATIVE:
 OPEN CARPAL TUNNEL RELEASE
 ENDOSCOPIC CARPAL TUNNEL RELEASE
OPEN CARPAL TUNNEL RELEASE:
•
 Incision & deeper dissection
are performed ulnar to the
longitudinal plane between
the ulnar border of the ring
finger & a point along the wrist
crease noted by flexing the
ring finger against the palm.
 Transverse carpal ligament is
divided proximally to distally.
 COMPLICATIONS:
• Incomplete division of transverse
carpal ligament.
• Division of palmar cutaneous branch or
motor branch of median nerve.
• Injury to superficial palmar vascular arch.
• Reflex sympathetic dystrophy.
• Palmar hematoma
• Loss of grip strength.
ENDOSCOPIC CARPAL TUNNEL RELEASE
Emerging technology for open decompression of the carpal tunnel.
CONTRAINDICATIONS:
 Co existent ulnar tunnel release.
 Limited wrist & finger extension.
 Tenosynovitis
 Previous surgery
ANTERIOR INTEROSSEOUS SYNDROME
 Anterior interosseous branch of the median nerve supplies the flexor
digitorum profundus to the index finger, flexor pollicis longus &
pronator quadratus.
 Provides sensation to the volar aspect of carpus.
 POTENTIAL SITES OF COMPRESSION:
 Fibrous bands of the flexor digitorum superficialis
 Fibrous bands of the deep or superficial heads of the pronator teres.
 LESS COMMMON CAUSES
 Anomalous muscles
 Enlarged / thrombosed vessels
 Tumours
 Enlarged bursae
CLINICAL FEATURES:
 Weakness of flexion in the IP joint of the thumb.
 Weakness of flexion in the DIP joint of index finger.
 No sensory loss
 Pain is exacerbated by exercise & relieved by rest.
 Number of cases occur due to a viral neuropathy.
TREATMENT
 INITIALLY: CONSERVATIVE
 SURGICAL: INDICATIONS
 No resolution of symptoms
 Severe symptoms
 SURGICAL EXPLORATION: Identification & division of the offending structure.
PRONATOR SYNDROME
Anatomical sites of compression:
 Below lacertus fibrosus
 Between the 2 heads of pronator teres
CLINICAL FEATURES
Ache or discomfort in the forearm associated
with weakness or clumsiness of the hand.
Numbness in the distribution of the median nerve.
Night pain is not common.
Phalen’s test & Tinel's sign: negative
Difficult to demonstrate electrophysiological
abnormality.
TREATMENT
 CONSERVATIVE:
 NSAID’S
 Splinting with the elbow at 90 degrees, slight
forearm pronation & wrist flexion.
 SURGICAL:
 Exploration of distal 5 to 8 cm of the course of the
median nerve in the arm combined with its
course in the upper forearm.
 Possible sites checked
 Appropriate release is done.
ULNAR NERVE
 Ulnar nerve gets entrapped at 2 common sites:
 At the elbow (cubital tunnel syndrome)
 Guyon’s canal (ulnar tunnel syndrome)
CUBITAL TUNNEL SYNDROME
 Second commonest nerve entrapment of the upper
limb
 ANATOMY: CUBITAL TUNNEL
 Starts at the groove between the
olecranon & the medial epicondyle.
 Tunnel is formed by a fibrous arch
connecting the 2 heads of the flexor
carpi ulnaris & lies just distal to the medial
epicondyle.
CAUSES OF ENTRAPMENT
 ARCADE OF STRUTHER’S: Formed by superficial
muscle fibres of the medial head of triceps
attaching to the medial epicondyle ridge by a
thickened condensation of fascia.
 Tight fascial band over the cubital tunnel.
 Medial head of triceps
 Aponeurosis of flexor carpi ulnaris
 Recurrent subluxation of ulnar nerve, results in
neuritis.
 Osteophytic spurs
 Cubitus valgus following supra condylar
fracture.
CLINICAL FEATURES
 Numbness involving the little finger & the
ulnar half of the ring finger.
 Hand weakness & clumsiness
 Tenderness over the ulnar nerve at the elbow.
 Tinel’s sign is positive: exacerbation of
paraesthesia’s with light percussion over the
ulnar nerve.
 Advanced cases : clawing of the ring & little
fingers
TREATMENT
 NON OPERATIVE: Early stages
 Activity modification
 Immobilization of the elbow in 30 degrees of extension, followed by periods of
mobilization with elbow padding.
 SURGICAL:
 Decompression of the nerve by dividing of the basic offending structure.
 Anterior transposition of the ulnar nerve
 Medial epicondylectomy
ULNAR TUNNEL SYNDROME
 Ulnar nerve is compressed as it passes through GUYON’S canal in the wrist.
 Less common than entrapment of the ulnar nerve at the elbow.
ANATOMY: GUYON’S CANAL
 ROOF: composed of palmar carpal ligament
blending into the FCU tendon attaching to the
pisiform & the pisiohamate ligaments.
 Medial wall : pisiform & pisiohamate ligament.
 Lateral wall: hook of hamate & some fibres of the
transverse carpal ligament.
 Ulnar nerve enters guyon’s canal accompanied by
ulnar A & Ulnar V.
 Guyon’s canal lies in the space between flexor
retinaculum & volar carpal ligaments.
 The anatomy of distal ulnar tunnel is divided
into 3 zones.
 Zone 1:proximal to the bifurcation of the ulnar
nerve & consists of both sensory & motor fibres
of the nerve.
 Zone 2: represents the motor branch of the
ulnar N distal to the bifurcation.
 Zone 3: represents the sensory branches of the
ulnar nerve beyond its bifurcation.
Clinical presentations:
 ZONE 1 LESIONS : Mixed sensory & motor loss.
 ZONE 2 LESIONS : Isolated motor deficit.
 ZONE 3 LESIONS : Isolated ulnar N sensory loss.
 Common Causes in zone 1 & 2: ganglions, fractures of the hook of hamate.
 Zone 3: ulnar artery thrombosis
OTHER CAUSES:
 Malunited fracture of fourth/fifth metacarpal.
 Anomalous muscles
INVESTIGATIONS
 X RAY : Oblique/carpal tunnel views
 Delineate bony anatomy to diagnose hook of hamate fractures.
 MRI: Ganglia, space occupying lesions
TREATMENT
 Operative release of the canal by reflecting the FCU, pisiform & pisiohamate
ligament ulnarly.
 Distal deep fascia of the forearm below the wrist crease should be released.
 Resection of any space occupying lesion
 Treatment of hook of hamate fractures.
RADIAL NERVE
 PROPER RADIAL NERVE PALSY “SATURDAY NIGHT PALSY”
 POSTERIOR INTEROSSEOUS NERVE SYNDROME
 RADIAL TUNNEL SYNDROME
 WARTENBERG’S SYNDROME
Proper radial nerve

Rarely compressed by lateral head of triceps, typically compromised in setting of humerus
trauma or related surgical approaches

“Saturday night palsy”—Intoxicated patient passes out with arm hanging over chair, wakes up
with wrist drop.

Clinical findings include weakness of proper radial nerve–innervated muscles such as triceps,
brachioradialis, and ECRL plus muscles innervated by the PIN.

Sensory deficits may be present in distribution of superficial sensory branch.

EMG may be helpful.

May be initially observed but may be explored if no significant recovery after 3 months
Posterior interosseous nerve
compression syndrome
 PIN is a branch of the radial nerve that provides motor innervation to the extensor
compartment
 Symptoms include lateral elbow pain and distal muscle weakness.
 Radial deviation with active wrist extension because ECRL innervated by proper radial nerve
more proximally.
 PIN innervates the ECRB, supinator, EIP, ECU, extensor digitorum communis (EDC), extensor
digiti minimi, APL, EPB, and EPL.
 Patients may also have dorsal wrist pain, where the terminal nerve fibers provide sensory
innervation to the dorsal wrist capsule.
 Terminal branch is located on the floor of the fourth extensor compartment.
 EMG may be helpful.
 Anatomic sites of compression include
•
Fascial band at the radial head
•
Recurrent leash of Henry
•
Edge of the ECRB
•
Arcade of Frohse (the most common site, proximal edge of the supinator)
•
Distal edge of the supinator
 Unusual causes include chronic radial head dislocation, Monteggia fracturedislocation, radiocapitellar rheumatoid synovitis, and space-occupying elbow mass (e.g.,
lipoma)
 PIN palsy is differentiated from extensor tendon rupture by a normal wrist tenodesis test.
 Nonoperative treatment includes activity modification, splinting, and NSAIDs.
 Operative intervention warranted if no recovery by 3 months
 Surgical decompression of anatomic sites of compression provides good to excellent results
for 85% of patients.
RADIAL TUNNEL SYNDROME
 Characterized by lateral elbow and radial forearm
pain without motor or sensory dysfunction
 Provocative tests include resisted long-finger
extension (positive if resistance reproduces pain at
the radial tunnel) and resisted supination
 Lateral epicondylitis coexists in a small percentage
of patients.
 The point of maximum point tenderness is anterior
and distal to the lateral epicondyle.
 Despite affecting the same nerve (PIN) and sites of
compression,electrodiagnostic tests are typically normal.
 Prolonged nonoperative treatment for up to 1 year with activity
modification, splints, NSAIDs, and local modalities.
 Success of surgical decompression less predictable than for PIN
syndrome, with good to excellent results in only 50% to 80% after
prolonged postoperativerecovery
Wartenberg syndrome
 Compressive neuropathy of superficial sensory branch of the radial nerve
 Compressed between brachioradialis and ECRL with forearm pronation (by a scissor-like action
between the tendons)
 Symptoms include pain, numbness, and paresthesias over the dorsoradial hand.
 Provocative tests include forceful forearm pronation for 60 seconds and a Tinel sign over the nerve
 Initially treated by activity modification, splinting, and NSAIDs
 Surgical decompression warranted if 6-month trial of nonoperative treatment fails.
Education is not
the learning of
facts, But the
training of the
mind to think
Thank you