Hand II: Nerve Entrapment

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Hand IINerve Entrapment

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• Nadia Afridi MD, BSc (Med)
• Justin Paletz MD, FRCSC

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Basic Nerve Facts

• Anatomy
• Endoneurium
• Surrounds axons of peripheral nerves
• Fascicles
• Groups of axons
• Perineurium
• Surrounds individual fascicles
• Epineurium
• Intraneural
• Outer circumferential

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Basic Nerve Facts

• Anatomy
• Epineurium
• Intraneural
• Outer circumferential

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Basic Nerve Facts

• Anatomy
• Epineurial repair
• Outer epineurium sutured
• Fascicular bundle and perineurial repair
• Inner epineurium repaired
• Fascicular repair
• Perineurium sutured

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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

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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

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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

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Basic Nerve Facts

• Physiology
• Peripheral nerve transport mechanism
• Nutrient production
• Axoplasmic transport systems
• Breakdown products
• retrograde axoplasmic transport
• Disruption of transport systems

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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

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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

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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?

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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

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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 gt 2.5 cm
• Bridge with grafting, neurotization

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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

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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

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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

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Basic Nerve Facts

• Nerve repair
• Technique
• Group fascicular repair
• Possible when nerve transection at level of
  distinct functional groupings
• Motor-motor, sensory-sensory

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Basic Nerve Facts

• Nerve repair
• Nerve grafting
• Recommended for gaps gt 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

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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

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Nerve Entrapment

• Pathophysiology
• Systemic conditions
• Diabetes
• Alcoholism
• Hypothyroidism
• Exposure to industrial solvents
• Aging
• Depression of nerve function
• Lowers threshold for manifestation of compression
  neuropathy

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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

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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

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Nerve Entrapment

• Diagnosis
• History
• Patients description
• Duration and rate of progression
• Accurate localization of sensory loss
• Functional loss?
• Positional or nocturnal variance?
• Ask about legal involvement (USA)

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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

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Nerve Entrapment

• Diagnosis
• Sensory testing
• Semmes Weinstein
• Slowly adapting fibers
• Simple and inexpensive
• Vibration test
• Both most sensitive to progressive changes in
  nerve function

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Nerve Entrapment

• Diagnosis
• Electrodiagnostic studies
• Diagnostic gold standard
• Can aid in confirming diagnosis in some cases
• Fallible to user error and sensitivity of
  equipment

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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

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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

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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

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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

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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

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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

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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

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Median nerve - Entrapment

• Carpal Tunnel Syndrome
• Provocative tests
• Tinels sign
• Production of paresthesias with percussion at the
  carpal tunnel entrance
• Compression test
• Phalens test
• Symptoms with wrist flexion
• Reverse Phalens test
• Tourniquet test
• Above systolic pressure

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Median nerve - Entrapment

• Carpal Tunnel Syndrome
• Sensory testing early
• Semmes-Weinstein monofilament
• Vibrometry
• Late
• Two point discrimination

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Median nerve - Entrapment

• Carpal Tunnel Syndrome
• Electrodiagnostic studies
• Sensory and motor
• False negative as high as 10-20
• Diagnostic criteria
• Distal motor latency gt4.5 ms
• Distal sensory latency gt3.5 ms
• Asymmetry between hands
• Motor gt 1 ms, Sensory gt 0.5
• Comparison to ulnar nerve
• gt0.8 ms difference

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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

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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

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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

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Median nerve - Entrapment

• Pronator syndrome
• Presentation
• Distal arm and proximal forearm pain
• Pain increases with activity
• Paresthesias in median nerve distribution
• Tinels sign
• Positive over nerve
• Symptoms increased by resisted forceful pronation
  with elbow extended

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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

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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

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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

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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

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Median nerve - Entrapment

• Pronator syndrome
• Outcomes
• Almost successful as wrist median decompression
• 60-70 patients experience improvement

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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

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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

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Median nerve - Entrapment

• Anterior interosseus syndrome
• Electrodiagnostic studies
• Useful in this neuropathy
• Electromyographic evaluation
• Index FDP
• FPL
• Pronator quadratus

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Median nerve - Entrapment

• Anterior interosseus syndrome
• Treatment
• Conservative
• Splinting
• Observation
• NSAIDS
• Surgical
• Confirmation of diagnosis
• Failure of spontaneous improvement in 2 months

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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

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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

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Ulnar nerve

• Anatomy
• Small branches to elbow joint
• Innervates proximal FCU
• Dorsal sensory branch
• 4-6 cm proximal to wrist
• Outside of Guyons canal
• Nerve of Henle
• Ulnar artery

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Ulnar nerve

• Anatomy
• Guyons canal
• Triangular
• Roof
• Superficial volar carpal ligament
• Medial
• Pisiform
• Lateral
• Hook of the hamate

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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

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Ulnar nerve - Entrapment

• Ulnar tunnel syndrome
• Presentation
• Rare
• Entrapment of ulnar nerve in Guyons 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

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Ulnar nerve - Entrapment

• Ulnar tunnel syndrome
• Presentation
• Pain in wrist
• Numbness
• Tingling
• Burning
• Provocative tests
• Sustained hyperextension or flexion of wrist

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Ulnar nerve - Entrapment

• Ulnar tunnel syndrome
• Physical
• Intrinsic weakness
• Sensory testing
• Allen test
• Dopplers
• Fractures of hook of hamate
• Electrodiagnostic studies
• Establish diagnosis

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Ulnar nerve - Entrapment

• Ulnar tunnel syndrome
• Treatment
• Conservative
• Splint
• NSAIDs
• Surgical
• Refractory to conservative care
• Documented anatomic lesions
• Release Guyons canal

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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

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Ulnar nerve - Entrapment

• Cubital tunnel syndrome
• Physical
• Tinels 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

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Ulnar nerve - Entrapment

• Cubital tunnel syndrome
• Wartenbergs sign
• Abducted habitus of small finger
• Weak adduction by third palmar interosseus
• Froments sign
• Compensatory hyperflexion of thumb IP
• Hyperextension thumb MP secondary to loss of
  adductor pollicis and FPB (deep head)
• Claw hand
• MP hyperextension

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Ulnar nerve - Entrapment

• Cubital tunnel syndrome
• Provocative tests
• Elbow flexion test
• Increase in cubital tunnel pressure with flexion
• Aggravates symptoms

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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 (gt20)

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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

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Ulnar nerve - Entrapment

• Cubital tunnel syndrome
• Treatment
• Surgical
• Four approaches
• Simple decompression fascial covering split
• Medial humeral epicondylectomy
• Anterior subcutaneous transposition
• Anterior submuscular transposition
• Latter two approaches most commonly used

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Ulnar nerve - Entrapment

• Cubital tunnel syndrome
• Treatment
• Surgical
• Keypoints
• Protect medial antebrachial cutaneous nerve of
  forearm and its branches
• Release Arcade of Struthers and Osbornes
  ligament
• Split FCU but protect motor nerve
• Excise band between medial epicondyle and shaft
  of humerus
• Hemostasis

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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

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Ulnar nerve - Entrapment

• Cubital tunnel syndrome
• Outcomes
• Minimal compression
• Excellent results in 90
• Moderate compression
• Excellent in 50

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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

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Radial nerve

• Anatomy
• Travels
• Medial
• between brachialis and biceps tendon
• Lateral
• brachioradialis and ECRL, ECRB
• Supplies
• brachioradialis, ECRL, ECRB

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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

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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

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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

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Radial nerve - Entrapment

• Radial tunnel syndrome
• Electrodiagnostic studies
• Usually normal

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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

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Radial nerve - Entrapment

• Radial tunnel syndrome
• Treatment
• Surgical
• Indicated in failed conservative treatment
• CRITICAL release of
• Arcade of Froshe
• Vascular leash of Henry

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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

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Radial nerve - Entrapment

• Posterior interosseus compression
• Electrodiagnostic studies
• Can be confirmatory

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Radial nerve - Entrapment

• Posterior interosseus compression
• Treatment
• Conservative
• Splinting
• Systemic steroids (short course)
• Surgical
• Indicated if no recovery after 3 months of
  conservative treatment

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Radial nerve - Entrapment

• Wartenbergs 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
• deQuervains tenosynovitis

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Radial nerve - Entrapment

• Wartenbergs syndrome
• Provocative tests
• Forceful pronation of forearm against resistance
• 30-60 seconds
• Tightens brachioradialis across the nerve
• Diagnosis
• Electrodiagnostic studies
• Local anaesthetic block

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Radial nerve - Entrapment

• Wartenbergs syndrome
• Treatment
• Conservative
• Splinting
• NSAIDs
• Local steroid injection
• Changes in work activities
• Surgical
• Failed conservative treatment
• Release fascia of brachioradialis and ECRL