orthopedics,peripheral nerve injury.(dr.baxtiar rasul)

1. Peripheral nerve injuries

2. Structure of the nerve
Axon
myeline sheath
Schwann cell layer
Endoneurium
Perineurium
Epineurium

3. Pathology
The nerve is injured by:
Ischaemia
Compression
Traction
Laceration
burning

4. Types of injury
•Transient ischaemia
•Neurapraxia
•Axonotmesis
•Neurotmesis

5. Transient ischaemia
Acute nerve compression
→
Acute endoneural anoxia
→
Temporary numbness + muscle wasting
Recovery by 10 minutes

6. Neurapraxia
Chronic mechanical pressure
→
Demyelination of axon
Spontaneous recovery after few days or weeks

7. Axonotmesis
• Segmental interruption of the axons
• Loss of conduction
• But the neural tubes are intact
• Seen in closed fractures and dislocations
• Distal to the lesion → Wallerian degeneration
• Axonal regeneration occurs by formation of the new axonal processes
which grow at a speed of 1-2 mm per t

8. Neurotmesis
Division of the nerve trunk
Occurs in open wounds
Neural tubes are destroyed
A Neuroma is formed( regenerating fibers + Schwann cells + fibroblasts)
Function may be adequate but is never normal even after surgical repair.

9. Diagnosis
Symptoms: (1) Numbness
(2) Tingling
(3) Weakness
Signs: (1) Abnormal posture ( wrist drop)
(2) Atrophy of the muscles
(3) Change in sensibility
Tinels sign: shows progression in nerve recovery
Electrodiagnostic tests (1) level of injury
(2) Severity
(3) progress of nerve recovery

10. Obstetric brachial plexus injuries
Caused by excessive traction on the brachial plexus
during childbirth
.
C5+C6+C7+C8+T1
Clinical features:
•Difficult delivery
•Flail arm.
•Further examination reveals one of the following:
(A) Erb’s palsy
(B) klumpke’s palsy

12. Erb’s palsy:
Injury of C5+ C6
The arm is held to the side, internally rotated, and pronated.
(i.e paralysis of the abductors and external rotators of the
shoulder

+ the supinators)

15. Klumpke’s palsy:
Less common
The arm is flail and pale
All muscles of the fingers are paralyzed
± Ipsilateral Horner’s syndrome

16. Treatment:
If there is no biceps recovery by 3 months, surgery is performed:
If the roots are not avulsed: Nerve graft
If the roots are avulsed : Nerve transfer
If severe internal rotation : Subscapularis release ± tendon transfer
OR
Rotation osteotomy of the humerus
Physiotherapy in all cases
Prognosis in Klumpke’s palsy is poor.

18. Axillary nerve injury (C5)
Supplies (1) Deltoid
(2) Skin over the lower ½ of the deltoid.
Injured in (1) Shoulder dislocation
(2) # of humeral neck
Clinically
(1) Loss of abduction
(2) Numbness over the deltoid.

21. Treatment:
Spontaneous recovery during 8 weeks. If not:
Exploration + repair OR graft. If failed:
Tendon transfer OR Shoulder arthrodesis.
.