This document discusses peripheral nerve injuries, including: 1. It describes the different types and causes of peripheral nerve injuries, including trauma, disease, ischemia, and radiation. 2. It outlines the primary and secondary injury mechanisms and classifies nerve injuries using the Seddon and Sunderland classifications based on the anatomical disruption. 3. It explains the neuronal degeneration and regeneration process after a nerve injury.

1. Peripheral
Nerve
Injuries
Dr.Prateek Singh
intern
Dept. of Orthopaedics
BPKIHS

2. Peripheral Nerve

3. Coverings

4. Internal topography
Fascicular arrangement constantly change throughout
the course

5. Etiology of peripheral nerve injuries
1. Metabolic or collagen disease
2. Malignancy
3. Endo or exo-toxins
4. Ischaemia
5. Radiation * infection:leprosy
6. Trauma
 Thermal
 Chemical
 Mechanical

6. Primary injury
– Results from same trauma that injures a bone or
joint
– Radial nerve is the most commonly injured. Of
humeral shaft fractures, 14 % is complicated by
radial nerve injuries
– Displaced osseous fragments
– Stretching
– Manipulation
Secondary injury
– Results from involvement of nerve by infection, scar,
callous or vascular complications which may be
hematoma, AV fistula, Ischemia or aneurysm

7. Classification of nerve injuries
Seddon Classification
1.Neuropraxia:
1.Minor contusion or compression with preservation of axis –
cylinder of myelin sheath.
2.Impulse transmission physiologically interrupted.
3.Complete recovery in a few days to weeks
2.Axonotemesis :
1.More significant injury
2.Breakdown of axon and distal Wallerian degeneration but with
preservation of schwann cell & endoneurial tubes
3.Spontaneous regeneration with good functional recovery can be
expected
3. Neurotmesis
1.More severe injury
2.Complete anatomical severance, avulsion or crushing of nerve
3.Axon, Schwann cell & endoneurial tubes are completely
disrupted
4.Spontaneous recovery cannot be expected unless surgically
intervened

8. Sunderland Classification
 Each degree of injury suggesting a greater anatomical
disruption with its correspondingly altered prognosis
 Anatomically various degrees (1st – 5th) represent injury
to
 Myelin
 Axon
 Endoneurial tube & it’s content
 Perineurium
 Entire nerve trunk
 Sixth degree (Mackinson) or mixed injuries occur in
which a nerve trunk is partially severed and
remaining part of trunk sustains 1st to 4th degree
injury.
 Mixed recovery pattern depending on degree of
injury to each portion of nerve.

9. Neuronal degeneration and regeneration
• Any part of neuron detached from its
nucleus, degenerates & is destroyed by
phagocytosis.
• Distal – Secondary / Wallerian Degeneration
• Proximal - Primary / Traumatic / Retrograde
Degeneration
• Time required for degeneration varies between
sensory and motor fibers and is also related to size
& myelination of fibers
• Advancing Tinel sign and presence of motor march
phenomena are signs of regeneration

11. Diagnosis of Peripheral nerve
injuries
• History
– Which nerve ?
– What level ?
– What is the cause ?
– What degree of injury ?
– Old or fresh injury ?

12. Diagnosis of Peripheral nerve
injuries
1. Motor:
– 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)

13. 2. Sensory :
• Sensory loss usually follows a definite
anatomical pattern, although factor of
overlap from adjacent nerves may be
present
• Autonomous zone
• Weber 2 point discrimination test
• Tinel’s sign

14. (3) Reflex
• Abolishes all reflexes transmitted by that
nerve, either afferent or efferent arc.
• Complete & incomplete lesion. So , not a
reliable guide to injury severity.
(4) Autonomic :
• Loss of sweating
• Loss of pilomotor response and
• Vasomotor paralysis in autonomous zone

15. (5) Others:
• Trophic Changes
• Esp. hand and feet
• Skin – thin, glistening, breaks easily to form
ulcers that heal slowly
• Fingernails
• Ridged, distorted and brittle
• Osteoporosis (Reflex sympathetic dystrophy)

16. Test for peripheral nerves of upper limb
• Radial nerve injury
– very high / high / low injury
– Wrist drop / finger drop / thumb drop
– Test for triceps/ /Brachioradialis/ wrist extensors /
extensor digitorum / EPL
• Median nerve
– High / low injury
– Test for FPL / FDS / FDP (lat. half) / FCR / Abd.
Pollicis brevis ( pen test) / Oppenens pollicis
– See for pointing index / complete claw hand

17. • Ulnar nerve
– High / low palsy –ulnar paradox
– Test for FCU / Abd. digiti minimi / Interossei (dorsal -
Egawa’s test ; palmar – card test ) / lumbricals /Add.
Pollicis (Froment’s sign / book test )
– Ulnar claw hand

18. Electrodiagnostic studies
• Electromyography
• Nerve conduction velocity
• Strength duration curve

19. Time of Surgery
• Primary repair : First 6 – 8 hours
• Delayed primary repair : First 7 – 18 days
• Secondary repair : > 3 weeks

20. Indications for surgery
1. When a sharp injury has obviously divided a
nerve.
2. When abrading, avulsing or blast wounds have
rendered the condition of nerve unknown
3. When a nerve deficit follows a blunt or closed
trauma & no clinical or electrical evidence of
regeneration has occurred after an appropriate
time
4. 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.

21. Types of Nerve Repair :
1. Endoneurolysis
2. Partial Neurorrhaphy
3. Neurorrhaphy
1. Epineural
2. Epi-perineural
3. Perineural
4. Nerve grafting

26. Method of closing gap between nerve ends
1. Mobilization ( critical nerve gap distance – value
of Grantham)
2. Positioning of extremity
– Flex knee and elbow < 90°
– Flex wrist < 40°
1. Transposition
2. Bone resection
3. Nerve stretching & bulb sutures
4. Nerve grafting
5. Nerve crossing ( pedicle grafting )

27. Factors 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

28. Options
• Orthoses
• Tendon transfers
• Bony blocks
• Arthrodesis

29. Thank You