Transcript Heat Shock Proteins and the Rat Dorsal Island Flap

Hand II:
Nerve Entrapment
Nadia Afridi MD, BSc (Med)
Justin Paletz MD, FRCSC
Basic Nerve Facts
 Anatomy
– Endoneurium
• Surrounds axons of
peripheral nerves
– Fascicles
• Groups of axons
– Perineurium
• Surrounds individual
fascicles
– Epineurium
• Intraneural
• Outer
circumferential
Basic Nerve Facts
 Anatomy
– Epineurium
• Intraneural
• Outer
circumferential
Basic Nerve Facts
 Anatomy
– Epineurial repair
• Outer epineurium
sutured
– Fascicular bundle
and perineurial
repair
• Inner epineurium
repaired
– Fascicular repair
• Perineurium sutured
Basic Nerve Facts
Anatomy
– Vascular supply
• Arteriae nervorum
– Enter nerve segmentally
– Divide into longitudinal superficial and
interfascicular arterioles
– Longitudinal epineurial and perineurial vessels
• ALLOW FOR INTRANEURAL DISSECTION
FOR FASCICULAR REPAIR
– Internal neural anatomy
• Discrete bundles and branches
Basic Nerve Facts
Physiology
– Peripheral nerve signaling
• Localized potentials
– Short distances
– Decrease over distance
– Key for intercellular junctions and sensory nerve
endings
• Action potentials
– Conducted impulses that DO NOT decrease over
distance
Basic Nerve Facts
Physiology
– Peripheral nerve signaling
• Action potentials
– Unmyelinated fibers
• Rate of conduction directly proportional to
cross section of axon
– Myelinated fibers
• Impulse jumps from each site of interrupted
myelin sheath (Node of Ranvier)
• SALTATORY CONDUCTION
Basic Nerve Facts
Physiology
– Peripheral nerve transport mechanism
• Nutrient production
• Axoplasmic transport systems
• Breakdown products
– retrograde axoplasmic transport
• Disruption of transport systems
Basic Nerve Facts
Nerve injury
– Two classification systems
• Seddon
– Neuropraxia, axonotomesis, neurotmesis
– Based on clinical evaluation and judgment of injury
– Preoperative assessment
• Sunderland
– 1st to 5th degree
– Histology
– Applicable after nerve exploration
Basic Nerve Facts
Nerve repair
– Timing
• Functional results of primary and early
secondary nerve repair similar
• Primary best:
–
–
–
–
–
–
Proximal injuries
Identifiable nerve ends
Minimal contamination
Without associated injuries
Healthy patient
Trained surgeon
• Delayed primary repair within 7 days
Basic Nerve Facts
Nerve repair
– Timing
• Secondary repair
– After 7 days
– Nerve stumps approximated and tagged
– Repair within 6 months
• Better result than after 6 months
• Optimal timing of repair
– Controversial
• Immediate
• 3 weeks - fibrosis ideal for repair?
Basic Nerve Facts
Nerve repair
– Patient age
• Younger patient
– Better functional outcome
– Optimal recovery in less than 20 years of age
• Motor/sensory nerve
– Digital nerve repairs
• Good results up to 50 years of age
– Condition of the wound
• Increased intraneural damage with extensive
injuries
Basic Nerve Facts
Nerve repair
– Level of Injury
• More proximal injury
– Worse functional return
– Tension of repair
• Elasticity of neural tissues
• Elongation by 20%
– After this point nerve conductivity diminishes
– Gap size
• Worse results with gap > 2.5 cm
• Bridge with grafting, neurotization
Basic Nerve Facts
Nerve repair
– Technique
• Alignment
• Precise match of motor and sensory fascicles
• No significant difference in outcome by type
of repair
– Epineurial
– Perineurial
– Group Fascicular
Basic Nerve Facts
 Nerve repair
– Technique
• Epineurial
– Conventional technique
– Aligned with two or three sutures
– Advantages:
• Short execution time
• Technical ease
• Minimal magnification
• Intraneural contents undisrupted
– Disadvantages
• Imprecise alignment
• Performance by poorly trained personnel
Basic Nerve Facts
 Nerve repair
– Technique
• Perineurial (Fascicular or Funicular)
– Technique of choice in nerve grafting
– Best in nerves with fewer than 5 fascicles
– Advantages:
• Better fascicular alignment
• More axons entering endoneurial tubes
– Disadvantages:
• Longer operative time
• Increased fibrosis at suture site
• Vascular compromise of fasciculi
• Trauma to nerve
Basic Nerve Facts
Nerve repair
– Technique
• Group fascicular repair
– Possible when nerve transection at level of distinct
functional groupings
– Motor-motor, sensory-sensory
Basic Nerve Facts
Nerve repair
– Nerve grafting
• Recommended for gaps > 2 cm
• Interfascicular technique
• Best recovery if grafting performed between
6-12 months postinjury
• Sural nerve most common donor
• Multiple other described techniques:
– Vascularized nerve
– Various donors
Nerve Entrapment
Epidemiology
– Increasing rate of CTS
– Risk factor:
•
•
•
•
Female gender
Pregnancy
Diabetes
Rheumatoid arthritis
– Small carpal tunnel area not a risk factor
– No universal acceptance of job related
issues
Nerve Entrapment
Pathophysiology
– Systemic conditions
•
•
•
•
•
Diabetes
Alcoholism
Hypothyroidism
Exposure to industrial solvents
Aging
– Depression of nerve function
– Lowers threshold for manifestation of
compression neuropathy
Nerve Entrapment
Pathophysiology
– Ischemia/Mechanical Factors
• Earliest manifestation
– Reduced epineurial blood flow
– 20-30 mmHg compression
• Interference in venular flow
– 40-50 mmHg
• Impairment of arteriolar and interfascicular
capillary flow
– 60-80 mmHg
• Complete blockage of nerve perfusion
Nerve Entrapment
Pathophysiology
– Double crush phenomenon
• Axoplasmic transport systems disrupted
– Mechanical
– Diabetes etc…
• “A nerve with a conduction disorder at one
level is more vulnerable to a conduction
disorder at a second level”
Nerve Entrapment
Diagnosis
– History
•
•
•
•
•
•
Patient’s description
Duration and rate of progression
Accurate localization of sensory loss
Functional loss?
Positional or nocturnal variance?
Ask about legal involvement (USA)
Nerve Entrapment
Diagnosis
– Physical
• Brief limb survey
• Screening sensation test
– Light touch of affected area compared to known
normal
• Two point discrimination
– Can remain normal if minimal number of fibers
functioning normally
Nerve Entrapment
Diagnosis
– Sensory testing
• Semmes Weinstein
– Slowly adapting fibers
– Simple and inexpensive
• Vibration test
• Both most sensitive to progressive changes
in nerve function
Nerve Entrapment
Diagnosis
– Electrodiagnostic studies
• Diagnostic gold standard
• Can aid in confirming diagnosis in some
cases
• Fallible to user error and sensitivity of
equipment
Nerve Entrapment
Diagnosis
– Radiographic examination
• Occasionally useful
• Rule out neck pathology in diffuse
presentation
• Cxray
– Pancoast tumor
• MRI
– Best study for showing nerve compression at
brachial plexus down to carpal tunnel
Median nerve
 Anatomy
– Derived from C5-T1
– Runs medial to axillary and
brachial arteries
– Passes deep to bicipital
aponeurosis and flexor
muscle mass
– 80% passes between two
heads of pronator teres
– Continues between FDS and
FDP
– Emerges in forearm radial to
superficialis tendons
– Passes under transverse
carpal ligament
Median nerve
 Anatomy
– Superficial trunk supplies:
•
•
•
•
Pronator teres
FCR
PL
FDS index
– Deep trunk supplies (anterior interosseus nerve):
•
•
•
•
FDP to index and middle
FPL
Pronator quadratus
Sensation to radial carpal joint
Median nerve
Anatomy
– 5-6 cm proximal to anterior wrist crease
• Palmar cutaneous branch
– Innervates skin at base of palm
– Does not pass through carpal tunnel
– Beneath transverse carpal ligament
• Recurrent motor branch
– Supplies thenar muscles, 1st and 2nd lumbricals
• Three proper digital nerves and two common
digital nerves
Median nerve
Anatomy
– Martin-Gruber anastomosis
• Motor connnection median and ulnar nerve
proximal forearm
• Between anterior interosseus nerve and ulnar
nerve more distally
– Riche-Cannieu anastomoses
• Motor connection between median and ulnar
motor branches in the palm
Median nerve
 Anatomy
– Carpal tunnel
• Boundaries
– Roof (Volar):
• Transverse carpal
ligament
– Floor (Dorsal):
• Volar ligaments and
carpal bones
– Lateral wall (Radial):
• Scaphoid tuberosity
and trapezial crest
– Medial wall (Ulnar):
• Pisiform and hook
of the hamate
Median nerve - Entrapment
Carpal Tunnel Syndrome
• Pain and paresthesias palmar radial hand
–
–
–
–
–
Worse at night
Driving
Exacerbated with repetitive forceful use
Sensation of swelling
Normal sensation in area of palmar cutaneous
branch of median nerve
• Motor function
– Late sign
• Clumsiness
• Thenar atrophy
• Weak thumb abduction
Median nerve - Entrapment
Carpal Tunnel Syndrome
– Provocative tests
• Tinel’s sign
– Production of paresthesias with percussion at the
carpal tunnel entrance
• Compression test
• Phalen’s test
– Symptoms with wrist flexion
• Reverse Phalen’s test
• Tourniquet test
– Above systolic pressure
Median nerve - Entrapment
Carpal Tunnel Syndrome
– Sensory testing – early
• Semmes-Weinstein monofilament
• Vibrometry
– Late
• Two point discrimination
Median nerve - Entrapment
Carpal Tunnel Syndrome
– Electrodiagnostic studies
• Sensory and motor
– False negative as high as 10-20%
• Diagnostic criteria
– Distal motor latency >4.5 ms
– Distal sensory latency >3.5 ms
– Asymmetry between hands
• Motor > 1 ms, Sensory > 0.5
• Comparison to ulnar nerve
– >0.8 ms difference
Median nerve - Entrapment
 Carpal Tunnel Syndrome
– Treatment
• Conservative
–
–
–
–
Attempt in mild disease with intermittent paresthesias
Splinting to prevent wrist flexion
Systemic anti-inflammatory medications
Steroid injection
• Controversial
• Transient relief in 80%
• 22% symptom free after 12 months
– Ergonomic adjustments
– Failure to respond
• Surgical decompression
Median nerve - Entrapment
Carpal Tunnel Syndrome
– Surgical technique
• Open
– Variety of skin incisions
– Incision between 3rd and 4th metacarpals
– Caution re: palmar cutaneous branch and
recurrent motor branch
– Through palmar fascia
– Transection of transverse carpal ligament
• Endoscopic
– Controversial
Median nerve - Entrapment
Carpal Tunnel Syndrome
– Outcomes
• 80% patients experience excellent or good
results
• 10-15% fair results
• 5-10% poor results
• Pain relief IMMEDIATE
• Maximum recovery 6-12 months after surgery
– Numbness
– Weakness
Median nerve - Entrapment
Pronator syndrome
– Presentation:
•
•
•
•
Distal arm and proximal forearm pain
Pain increases with activity
Paresthesias in median nerve distribution
Tinel’s sign
– Positive over nerve
• Symptoms increased by resisted forceful
pronation with elbow extended
Median nerve - Entrapment
 Pronator syndrome
– Four sites median
compression at elbow:
• Ligament of Struthers
– Supracondylar
process of humerus
to superficial head of
pronator
• Lacertus fibrosus
– Biceps
• Pronator teres
• FDS fibrous arch of
origin
Median nerve - Entrapment
Pronator syndrome
– Provocative tests
• Ligament of Struthers
– Elbow flexion
• Lacertus fibrosus
– Resisted elbow flexion
• Pronator teres
– Resisted pronation with the elbow extended and
digits relaxed
• FDS fibrous arch
– Median symptoms with resisted FDS of the long
finger
Median nerve - Entrapment
Pronator syndrome
– Electrodiagnostic studies
• Nerve conduction and EMG not helpful
– 50% of diagnoses can be confirmed with EMG
• Serial clinical exams more useful
– Persistent pain and physical findings
– Normal electrodiagnostic studies
– Diagnosis still relevant
Median nerve - Entrapment
Pronator syndrome
– Treatment
• Conservative
– Same
• Operative
– Above elbow flexion crease to distal forearm
– Examine and release all four sites of possible
entrapment
Median nerve - Entrapment
Pronator syndrome
– Outcomes
• Almost successful as wrist median
decompression
• 60-70% patients experience improvement
Median nerve - Entrapment
Anterior interosseus syndrome
– Presentation
•
•
•
•
•
Vague deep forearm pain
Aggravated by activity
Relieved by rest
No sensory disturbance
Weakness of index FDP, FPL
– Characteristic posture
• Unable to form “6” with fingers
Median nerve - Entrapment
Anterior interosseus syndrome
– Provocative tests
• Test pronator quadratus
– Resisted forced supination with elbow maximally
flexed
– Eliminated effect of humeral pronator teres
• Pain elicited with resisted flexion long FDS
– Site of compression
• Fibrous bands in pronator teres
Median nerve - Entrapment
Anterior interosseus syndrome
– Electrodiagnostic studies
• Useful in this neuropathy
• Electromyographic evaluation
– Index FDP
– FPL
– Pronator quadratus
Median nerve - Entrapment
Anterior interosseus syndrome
– Treatment
• Conservative
– Splinting
– Observation
– NSAIDS
• Surgical
– Confirmation of diagnosis
– Failure of spontaneous improvement in 2 months
Ulnar nerve
Anatomy
– Continuation of medial cord of brachial
plexus
• C8 and T1
– Axilla
• Lies deep to pectoralis minor
• Between axillary artery and vein
– Descends in arm medial to brachial
artery between coracobrachialis and
triceps
Ulnar nerve
 Anatomy
– Passes through medial intermuscular septum
– Lies in groove at medial head of triceps
– Fascial arch
• Arcade of Struthers
– Lies across nerve 70% patients
– 7-10 cm proximal to medial epicondyle
– Passes posterior to medial epicondyle
– Cubital tunnel
– Passes between humeral and ulnar heads of
FCU
Ulnar nerve
 Anatomy
– Small branches to
elbow joint
– Innervates proximal
FCU
– Dorsal sensory
branch
• 4-6 cm proximal to
wrist
• Outside of Guyon’s
canal
– Nerve of Henle
• Ulnar artery
Ulnar nerve
 Anatomy
– Guyon’s canal
• Triangular
• Roof
– Superficial volar
carpal ligament
• Medial
– Pisiform
• Lateral
– Hook of the
hamate
Ulnar nerve
 Anatomy
– Hand
• Deep (motor) branch
–
–
–
–
–
–
Hypothenar eminence
Midpalm
Interossei
Two ulnar lumbricals
Adductor pollicis
Deep head of FPB
• Superficial (sensory) branch
– Radial carpal joint
– Ulnar aspect hand
• Palmar cutaneous branch of ulnar nerve absent when
nerve of Henle present
Ulnar nerve - Entrapment
Ulnar tunnel syndrome
– Presentation:
• Rare
• Entrapment of ulnar nerve in Guyon’s canal
– Numbness in ulnar two digits
– Sensation in dorsal sensory branch spared
• Pure motor, sensory or mixed
• Etiologic factors
– Use of “heel of hand”
– Space occupying lesions
• Ganglia, bony, pseudoaneurysms
Ulnar nerve - Entrapment
Ulnar tunnel syndrome
– Presentation:
• Pain in wrist
– Numbness
– Tingling
– Burning
– Provocative tests
• Sustained hyperextension or flexion of wrist
Ulnar nerve - Entrapment
Ulnar tunnel syndrome
– Physical
• Intrinsic weakness
• Sensory testing
• Allen test
– Dopplers
• Fractures of hook of hamate
– Electrodiagnostic studies
• Establish diagnosis
Ulnar nerve - Entrapment
Ulnar tunnel syndrome
– Treatment
• Conservative
– Splint
– NSAIDs
• Surgical
– Refractory to conservative care
– Documented anatomic lesions
– Release Guyon’s canal
Ulnar nerve - Entrapment
 Cubital tunnel syndrome
– “Tardy ulnar palsy”
– Presentation:
•
•
•
•
•
2nd most common site
Repetitive elbow flexion-extension
Elbow pain
Sensory disturbance in ulnar nerve distribution
Weakness of ulnar intrinsics
– 1st dorsal interosseus
– Adductor pollicis
– Key pinch strength
• Interosseus wasting
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Physical
•
•
•
•
•
•
•
Tinel’s at medial epicondyle
Subluxation of nerve
Snapping of triceps
Decreased pinch strength
Intrinsic atrophy
Weakness in small FDP and FCU
“wish sign”
– Crossing middle over index
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Wartenberg’s sign
• Abducted habitus of small finger
• Weak adduction by third palmar interosseus
– Froment’s sign
• Compensatory hyperflexion of thumb IP
• Hyperextension thumb MP secondary to loss
of adductor pollicis and FPB (deep head)
– Claw hand
• MP hyperextension
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Provocative tests
• Elbow flexion test
– Increase in cubital tunnel pressure with flexion
– Aggravates symptoms
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Electrodiagnostic studies
• Can confirm cubital tunnel
• Conduction velocities useful
– Vary with elbow position
– Three segments:
• Above elbow
• Across elbow
• Forearm
– Dip in CV across elbow with forearm recovery
significant (>20%)
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Treatment
• Conservative management
–
–
–
–
Splint
NSAIDs
Avoidance of elbow trauma
Inappropriate to attempt if:
• MUSCLE ATROPHY, WEAKNESS OR
PERMANENT SENSORY CHANGES
Ulnar nerve - Entrapment
 Cubital tunnel syndrome
– Treatment
•
Surgical
– Four approaches:
1. Simple decompression – fascial covering
split
2. Medial humeral epicondylectomy
3. Anterior subcutaneous transposition
4. Anterior submuscular transposition
– Latter two approaches most commonly used
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Treatment
• Surgical
– Keypoints:
• Protect medial antebrachial cutaneous nerve
of forearm and its branches
• Release Arcade of Struthers and Osborne’s
ligament
• Split FCU but protect motor nerve
• Excise band between medial epicondyle and
shaft of humerus
• Hemostasis
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Treatment
• Surgical
– Technique
• Incision midway between olecranon and
medial epicondyle
• 8 cm proximal and 6 cm distal
• Identification proximally and distal dissection
• Cubital tunnel release
• Protect articular sensory and FCU branches
• Release of intermuscular septum
Ulnar nerve - Entrapment
Cubital tunnel syndrome
– Outcomes
• Minimal compression
– Excellent results in 90%
• Moderate compression
– Excellent in 50%
Radial nerve
 Anatomy
– Arises from C5-T1
(posterior cord)
– Descends around
humerus in spiral radial
groove beneath lateral
head of triceps
– Emerges through lateral
intermuscular septum
• 10-15 cm proximal to
lateral epicondyle
Radial nerve
 Anatomy
– Travels:
• Medial
– between brachialis
and biceps tendon
• Lateral
– brachioradialis and
ECRL, ECRB
– Supplies:
• brachioradialis, ECRL,
ECRB
Radial nerve
Anatomy
– Divides at elbow into:
• Superficial sensory division
– Travels under brachioradialis
– Emerges at midforearm subcutaneously
• Deep motor branch
– Posterior interosseus nerve
– Passes deep under fibrous proximal margin of
supinator
• Arcade of Froshe
– Innervation to extensors, sensory to wrist
Radial nerve - Entrapment
Radial tunnel syndrome
– Presentation
• Pain localized to tender extensor muscle
mass
• Radiates to wrist and dorsum hand
• Worse with use of arm
• Heaviness and fatigability
• Often misdiagnosed as lateral epicondylitis
• Involves both divisions of radial nerve
– Weakness with digital extension
Radial nerve - Entrapment
Radial tunnel syndrome
– Physical examination
• Tenderness over “mobile wad”
– Brachioradialis and radial wrist extensors
– Provocative tests
• Firm pressure over radial nerve at supinator
muscle
• Third finger test
– Increased pain with resisted extension of long
finger with elbow extended
• Resisted supination
Radial nerve - Entrapment
Radial tunnel syndrome
– Electrodiagnostic studies
• Usually normal
Radial nerve - Entrapment
Radial tunnel syndrome
– Treatment
• Conservative
– Rest from repetitive motions
– Splints
– Concurrent lateral epicondylitis
• Steroid injection
– Spontaneous remission can occur in mild cases
Radial nerve - Entrapment
Radial tunnel syndrome
– Treatment
• Surgical
– Indicated in failed conservative treatment
– CRITICAL release of:
• Arcade of Froshe
• Vascular leash of Henry
Radial nerve - Entrapment
Posterior interosseus compression
– Presentation
• Aching pain
– Similar to radial tunnel syndrome
• Weakness of digital extensors
• No sensory disturbance
– Physical
• Weakness of ECU, thumb and finger
extensor, APL
Radial nerve - Entrapment
Posterior interosseus compression
– Electrodiagnostic studies
• Can be confirmatory
Radial nerve - Entrapment
Posterior interosseus compression
– Treatment
• Conservative
– Splinting
– Systemic steroids (short course)
• Surgical
– Indicated if no recovery after 3 months of
conservative treatment
Radial nerve - Entrapment
Wartenberg’s syndrome
– Presentation
• Involvement of superficial sensory branch of
radial nerve
– Dorsoradial aspect of the hand
• Emerges between brachioradialis and ECRL
– Compressed by scissor like action with pronation
• Complaints of pain and paresthesias with
forearm pronated
• Differentiate
– deQuervain’s tenosynovitis
Radial nerve - Entrapment
Wartenberg’s syndrome
– Provocative tests
• Forceful pronation of forearm against
resistance
– 30-60 seconds
– Tightens brachioradialis across the nerve
– Diagnosis
• Electrodiagnostic studies
• Local anaesthetic block
Radial nerve - Entrapment
Wartenberg’s syndrome
– Treatment
• Conservative
–
–
–
–
Splinting
NSAIDs
Local steroid injection
Changes in work activities
• Surgical
– Failed conservative treatment
– Release fascia of brachioradialis and ECRL