2. OutlineOutline
• Carpal Tunnel Syndrome
• Median nerve entrapment
• Ulnar nerve entrapment
– At the elbow
– At the wrist
• Radial nerve entrapment
• TOS
• Sciatic nerve entrapment
• Peroneal nerve entrapment
• Tarsal tunnel syndrome
• Lateral femoral cutaneous neuropathy
3. PathophysiologyPathophysiology
• Peripheral Nerves
– Motor, sensory, and autonomic axons + supporting
elements
– Schwann cells
• Unmyelinated fibers: multiple axons to one Schwann cell
• Myelinated fibers: single axon to multiple Schwann cells
– this segment of myelin is called an internode
– In between the internodes, there are the nodes of Ranvier
4. PathophysiologyPathophysiology
• Peripheral Nerves
– Connective and supporting tissue
• Several axons run together = fascicle
• Multiple fascicles = nerve
• Endoneurium = connective tissue inside a fascicle
• Perineurim = connective tissue circumferentially
surrounding a single fascicle
• Epineurium = connective tissue that binds fascicles
together into a nerve
5. PathophysiologyPathophysiology
• Peripheral Nerves
– Connective and supporting tissue
• Relevance
– Epineurium protects against compression
• Peroneal division of sciatic nerve is sensitive,
because it contains less epineurium
– Epineurium and perineurium protect against stretch
6. PathophysiologyPathophysiology
Seddon Process Sunderland
Neuropraxia Conduction block 1
Axonotmesis Loss of continuity: axonal
Intact endoneurium
2
Neurotmesis Loss of continuity:
axonal+endoneurial
Intact perineurium
3
Neurotmesis Loss of continuity:
axonal+endoneurial+perineurial
Intact epineurium
4
Neurotmesis Entire nerve trunk transection 5
7. PathophysiologyPathophysiology
• Neuropraxia (conduction block) is a
segmental block axonal conduction
– Nerve can conduct action potentials above
and below, but not across the damaged area
– Nerve is in continuity but does not conduct
– Focal demyelination leads to current leak in
internode
– Action potential cannot propagate across this
area
10. PathophysiologyPathophysiology
• Neurotmesis
– Nerve transection
– Loss of axonal and connective tissue
continuity
– Wallerian degeneration
– However, the loss of supporting element
continuity may lead to neuroma formation
11. PathophysiologyPathophysiology
• Focal slowing of nerve conduction is the
principle electrophysiological feature of
entrapment neuropathy
• Mild degrees of pressure (suprasystolic)
applied to the nerve for short periods
produce reversible dysfunction due to
ischemia
• Entrapped nerve may be more sensitive to
bouts of ischemia than normal nerves
13. PathophysiologyPathophysiology
• Focal slowing
• Segmental demyelination and remyelination
• Direct mechanical injury
• Chronic low pressure
• Friction
• Ischemia, fibrosis
• Short tourniquet application with high pressure is
not a relevant model of human entrapment
syndrome
14. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Cluster of signs and symptoms which
follow entrapment of median nerve in the
carpal tunnel
– Subclinical or clinical evidence of numbness,
paresthesias, dyesthesias, or weakness in the
median nerve distribution
– electrophysiological testing in the 1940’s
15. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
– Commonly confused with thoracic outlet
syndrome
– compression resulting in demyelination
followed by axonal degeneration
• Sensory and autonomic fibers usually affected first
• Motor compression follows later
16. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
– Morbidity
• Irreversible loss of median nerve function
• Surgical failure rates range from 2-31%
• Conservative failure rates 1-50%
17. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Epidemiology
– Race
• Whites are higher risk , whites have 2-3 times risk
compared to blacks)
• Very rare in non-white South Africans
– Sex: F:M ratio is 3-10:1
– Age
• Peak age is 45-60
• <10% of patients are under 31
19. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Carpal tunnel
– flexor
retinaculum( transvers
e carpal ligament)
• Continuation of arm
fascia
• Roof of carpal tunnel
proximal
distal
Median nerve
Median nerve
20. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Carpal tunnel
– transmits
• long flexors of the fingers and
thumb
– flexor digitorum superficialis
tendons are arranged in 2 rows
– flexor digitorum profundus
tendons are arranged in the
same coronal plane
– flexor pollicis longus tendon
• median nerve
– Just under flexor retinaculum
– Lateral side of the flexor
digitorum superficialis between
the flexor tendon of the middle
finger and the flexor carpi
radialis.
– Combination of lateral (C6-7)
and medial (C8-T1) cords of
brachial plexus
proximal
distal
Median nerve
Median nerve
22. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Etiology: multiple risk factors
• Genetics
– Linked to body morphology
– Linked to inherited medical conditions (DM,
Thyroid disease, hereditary neuropathies)
• Vocational
– Prolonged severe force through wrist, posturing of
wrist, high amounts of repetitive movements, and
exposure to vibration/cold
• Other factors
– Lack of aerobic exercise
– Pregnancy and breast feeding
– Use of wheelchairs and walking aids
24. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Clinical
– Intermittent symptoms and increase with
certain activities (driving, reading the paper,
painting)
– Bilateral symptoms
25. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Clinical
– Pain
• Aching over ventral wrist
• Nocturnal pain and burning
– Sensory abnormalities
• Hypesthesia and paresthesias
• ‘hands fall asleep’
• Thumb, index, middle, radial half of ring finger usually
affected
• Patients are often unable to localize symptoms
26. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Clinical
– Muscular atrophy and weakness are late findings
• Loss of hand power, especially precision grip in hand
– Autonomic changes
• ‘tight or swollen’ feeling in hands
• Increased sensitivity to temperature changes
• Skin color changes
27. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Physical Exam
• Special: no good clinical
exam, only supportive
– Phalen
• Tingling in median
nerve distribution
reproduce by full
wrist flexion for 1
minute
• 80% specificity but
lower sensitivity
– Reverse Phalen
• Wrist is held in
extension
28. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Physical Exam
– Carpal compression
test
• Firm pressure
directly over
carpal tunnel,
with both thumbs,
for 30 seconds
• Sensitivity 89%
• Specificity 96%
29. • Tinel's Sign
• Firm percussion
over the course of
the median nerve
just proximal to or
on top of the carpal
tunnel.
33. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Clinical Features
– Imaging (MRI or Ultrasound)
• Not considered routine for
CTS
– US high-resolUtion is a new
technology which is gaining
wider acceptance, since it is
non-invasive
Ultrasound: mn median nerve,
u:ulnar nerve, p: pisiform,
s:scaphoid
34. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Clinical Features
–Electrodiagnos
is
• First line
investigation
• Prognosticates
severity and
can be used to
follow disease
process over
time
Compound motor action potentials (CMAPs) in
a 56-year-old with bilateral CTS symptoms,
R>L. Distal motor latency was 5.7 ms on the R
and 4.3 ms on L. Median F-wave latency was
31.8 ms on the R and 29.3 ms on the L.
35. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Treatment
– Pharmacotherapy
• NSAIDS
• Diuretics
• Intratunnel steroid and local anesthetic injection
• Oral steroids
• Vitamin B6 or B12- no proven benefit
• Reduce intake of caffeine, nicotine, and alcohol
36. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Treatment
– Surgical
• Indicated for failure of
conservative care or
severe category at
initial presentation
• Release of transverse
carpal ligament (also
volar carpal ligament
and deep forearm
fascia)
– >90% early success
– 60% at 5 years
open
endoscopic
37. Carpal Tunnel SyndromeCarpal Tunnel Syndrome
• Treatment
– Surgical
• Debate surrounds open
vs. endoscopic
• Since disease is often
progressive, a growing
number of patients with
mild to moderate
disease may require
this option
open
endoscopic
38. Other median nerve compressionOther median nerve compression
syndromessyndromes
• At the shoulder
– Follows trauma or improper use of axillary crutches
– Other nerve compression syndromes may be present
– Forearm pronation is impaired
– Weak wrist flexion
– Weak wrist grasp
– Thumb flexion poor
– Difficulty with flexion of PIP joints
39. Other median nerve compressionOther median nerve compression
syndromessyndromes
• At the elbow
• Tx: neurolysis
• At the elbow
– Pronator syndrome
40. Other median nerve compressionOther median nerve compression
syndromessyndromes
• At the elbow
– Anterior interosseous nerve syndrome
• AIN arises from the median nerve, 5-8 cm distal to
the lateral epicondyle
• Etiology
– Trauma, inflammation
41. Other median nerve compressionOther median nerve compression
syndromessyndromes
• At the elbow
– Anterior interosseous
nerve syndrome
• Clinical
– Proximal forearm pain
• Physical exam
– Absence of flexion of
thumb interphalangeal
joint and the DIP joint
of index finger
42. Ulnar nerve compressionUlnar nerve compression
• At the elbow
• 2nd
most frequent upper extremity neuropathy
• Clinical
– Intermittent hypesethesias in the ulnar nerve
distribution
– Worsened with elbow flexion
– Night time shooting elbow pain
• weakness of grasp or pinch
43. Ulnar nerve compressionUlnar nerve compression
• Etiology-elbow
– Bony or scar impingement at the elbow
– Cubital tunnel syndrome
• Treatment
– Activity modification
– Splinting
– Surgical treatment
44. Radial nerve compressionRadial nerve compression
• High radial nerve lesions
– proximal to its division into the posterior interosseous
nerve and sensory branch
– Often traumatic
– High axillary lesions
• Triceps is affected
– Lesions distal to bifurcation
• Triceps is spared
– Brachioradialis
• Mild weakness of elbow flexion and supination
• Weakness of this muscle indicates high radial nerve injury
45. Radial nerve compressionRadial nerve compression
• Posterior interosseous nerve syndrome
– PIN is the deep muscular branch of radial nerve
– Bifurcation of radial to PIN and sensory branch is just
distal to elbow
– Compressed by tumors, ganglia, or elbow synovitis
– Weakness of digital and wrist extensor, but with radial
deviation
46. Radial nerve compressionRadial nerve compression
• Suerficial branch of radial nerve
– Damaged post-surgically or following wrist fracture or
wristwatch
• Anesthesia of the entire sensory zone of the radial nerve
47. Lower limb nerve compressionLower limb nerve compression
syndromesyndrome
• Sciatic
– Piriformis
• Nerve passes through or underneath the piriformis
– Affects the knee flexors and all muscles below
the knee
– Affects sensation of the entire foot except the
medial malleolus
– Rare, so evaluate other etiologies
– Tx: neurolysis
48. Lower limb nerve compressionLower limb nerve compression
syndromesyndrome
• Peroneal nerve
– Clinical features
• Foot drop
– Paralysis or weakness of foot dorsiflexors and everters
– Partial sensory loss
– EDx
• NCVs and EMGs
– Tx
• Bracing to protect foot drop
• surgery
49. Lower limb nerve compressionLower limb nerve compression
syndromesyndrome
• Tarsal Tunnel
– 2 types
• Anterior
– Pain and sensory loss in the distal portions of the deep
peroneal nerve
• Posterior (more common)
– Posterior tibial nerve is entrapped at the level of the medial
malleolus
– Clinical features
• Pain ins the sole of the foot
– Burning, unpleasant quality
– Pain worse after a day of activitiy
– Nocturnal pain
54. Mononeuritis MultiplexMononeuritis Multiplex
• Clinical
–Pain
•lancinating dysesthesias
–Sensory
•Paresthesias
•Hyper or Hypesthesia
–Motor
•Paresis
•Abnormal motor control
–Past medical history is essential
56. Mononeuritis MultiplexMononeuritis Multiplex
• Laboratory and imaging
– Labs drawn in accordance with suspicion about
primary process (CBC, Hepatitis screen, fasting blood
sugar, ESR, Lyme titers, HIV)
– Imaging studies are not needed
– Electrodiagnosis:
• Sensory NCS: decreased amplitude, decreased conduction
velocity only with large amount of fiber dropout
• Motor NCS: similar to axonal polyneuropathies or
entrapment neuropathies, i.e., reduced amplitude with
preservation of conduction velocity
– Biopsy
• To distinguish axonal degeneration from demyelination
• Histologically, perivascular inflammation, axonal loss
57. Mononeuritis MultiplexMononeuritis Multiplex
• Treatment
– PT: splinting, TENS, caution with modalities (if patient
is insensate)
– Pharmacotherapy
• AED’s
• TCA’s
• Opioids are not ideal for neuropathic pain
• Steroids (in the setting of vasculitis or temporal arteritis)
– Percutaneous procedures
• diagnostic peripheral nerve blocks, peripheral nerve catheter
with local anesthetic infusion, cervical epidural neuroplasty
with continuous infusion, Intrathecal trial of clonidine
• stellate ganglion
