This document summarizes peripheral nerve injuries. It describes the anatomy of spinal nerves and their components. It discusses the types of nerve injuries including neurapraxia, axonotmesis, and neurotmesis. Common sites of injury in the upper and lower limbs are provided. The stages of nerve injury and recovery are outlined. Methods of diagnosing nerve injuries through examination, tests like EMG and NCS, and imaging are presented. Surgical and non-surgical treatment options are summarized along with factors that influence recovery.

1. PERIPHERAL NERVE
INJURIES
DR SUPREETH
DR RAVI VARMA

2. ANATOMY OF THE SPINAL NERVES
• Each segmental spinal nerve is formed at or near its
intervertebral foramen by the union of its dorsal, or
sensory, root with its ventral, or motor, root.

3. • The somatic peripheral nervous system (PNS) is defined by the presence of Schwann cells
• This includes the primary roots, dorsal root ganglia, mixed spinal nerves, plexuses, nerve trunks,
autonomic nervous system, and cranial nerves III through XII

4. NOTE-
A single motor neuron supplies ten
to several thousand muscle fibres
the smaller the ratio, the finer the
movement

5. COMPONENTS OF SPINAL NERVE
• MOTOR
• SENSORY
• SYMPATHETIC

6. NEURONAL DEGENERATION AND REGENERATION
WALLERIAN DEGENERATION
RETROGADE DEGENERATION

7. CAUSES
1. LACERATION
2. COMPRESSION/ENTRAPMENT
3. TRACTION
4. BIRTH INJURIES
5. IATROGENIC
6. FRACTURE
7. METABOLIC DISTURBANCES
8. ISCHAEMIA
9. THERMAL /ELECTRICAL INJURIES

8. COMMON NERVE INJURIES
• UPPER LIMB
• Axillary nerve injury
• Radial nerve injury
• Median nerve injury
• Ulnar nerve injury
• LOWERLIMB
• Femoral nerve injury
• Sciatic nerve injury
• Peroneal nerve injury

9. NERVE INJURY & RECOVERY
Motor
Proprioception
Touch
Temperature
Pain
Sympathetic
Recovery
Injury

10. Seddon
BMJ
1942
Neurapraxia
(Transient Block)
Axonotmesis
(Lesion in Continuity)
Neurotmesis
(Division of a nerve)
Brain
1943
• Localised
degeneration of the
myelin sheaths
• Complete
interruption of axons
• Preservation of
supporting
structures (Schwann
tubes, endoneurium,
perineurium)
• All essential parts
destroyed
• Interruption can
occur without
apparent loss of
continuity

11. TRANSIENT ISCHAEMIA-
• Acute nerve compression causes numbness and tingling within 15 minutes
• loss of pain sensibility after 30 minutes and muscle weakness after 45 minutes
• Relief of compression is followed by intense paraesthesia lasting up to 5 minutes
• feeling is restored within 30 second
• TRANSIENT ENDONEURIAL ANOXIA AND THEY LEAVE NO TRACE OF NERVE DAMAGE.

12. NEURAPRAXIA
• ‘neurapraxia’ to describe a reversible block to nerve conduction
• minor contusion or compression of a peripheral nerve with preservation of the axis- cylinder
• Transmission of impulses is physiologically interrupted for a time
• recovery is complete in 3-6 weeks
• Tinel’s sign-negative

13. AXONOTMESIS
• designating more significant injury
• breakdown of the axon and distal wallerian degener-ation but with preservation of the Schwann cell
and endoneurial tubes.
• Spontaneous regeneration with good functional recovery can be expected
• Tinels sign-positive

14. NEUROTMESIS
• more severe injury
• complete anatomical severance of the nerve or extensive avulsing or crushing injury
• Axon,Schwann cell and endoneurial tubes , eperineurium and epineurium are disrupted to varying
degrees
• significant spontaneous recovery cannot be expected.

15. IN CLINICAL PRACTICE, HOW DO YOU DISTINGUISH?
AXONOTMESIS VERSUS NEUROTMESIS
• Nature of injury
• Serial observations
• Exploration
• Imaging

16. SUNDERLAND CLASSIFICATION
Sunderland
1951 I II III IV V
Focal
conduction
block
NO Wallerian
degeneration
Axonal
Disruption
Axon
+
Endoneurium
Disruption
Axon
+
Endoneurium
+
Perineurium
Disruption
Axon
+
Endoneurium
+
Perineurium
+
Epineurium
Disruption
Cross-innervation

17. • In this classification, peripheral nerve
injuries are arranged in ascending
order of severity
• Anatomically, the various degrees
represent injury to
• (1) myelin,
• (2) axon,
• (3) the endoneurial tube and its
contents,
• (4) perineurium, and
• (5) the entire nerve trunk

18. VI type-mackinnon or mixed injuries

19. DIAGNOSIS
• NOTE-Always test for nerve injuries following any significant trauma. And test
again after manipulation or operation, in case the nerve has been damaged
during treatment!
acute chronic

21. MUSCLE POWER
• Muscles supplied by the nerve
should be tested repeatedly
• Nerve regenaration at 1mm per
day
• MOTOR MARCH

22. SENSORY EXAMINATION
• Sensory loss usually follows a definite anatomical pattern,
• area supplied exclusively by the severed nerve and is
called the AUTONOMOUS ZONE
• Axonometesis –cross innervation

24. • RELEXES
• AUTONOMIC- SWEATING
• TROPHIC CHANGES
• NAIL CHANGES
• OSTEOPOROSIS

25. TINEL’S SIGN
• A classic sign of progressive nerve recovery is
peripheral tingling provoked by percussing
the nerve at the site of injury
• NOTE- where regenerating axons are most
sensitive

26. DIAGNOSTIC TESTS
• EMG-earliest indicator
• NERVE CONDUCTION STUDY
• SWEAT TEST
• MRI

27. TREATMENT
• Conservative
• surgical

28. PREREQUISITES FOR NERVE REPAIR
• Skeletal stability
• Healthy tissue bed
• Healthy nerve ends
• No undue tension
• Adequate soft tissue coverage

29. FACTORS
•AgePatient factor
• Level of injury (distal vs proximal)
• Type of nerve (pure vs mixed
functions)
• Condition of nerve ends
Injury factors
• Delay to repair
• Length of gap
Surgical
factors

30. INDICATION FOR SURGERY
• Sharp injury dividing a nerve
• Blast injury
• In a closed injury when no signs of recovery by appropriat time

31. TIME OF OPERATION
Open injury
Primary repair(6-8
hours)
Delayed primary
repair(7-18 days)
Secondary
repair(after 18 days)
Closed
injury
Conservative(splints)
Delayed intervention

32. GOOD PROGNOSTIC FACTORS
• G-growing age
• O-only motor
• O-only sensory
• D-distal lesion
• N-neuropraxia
• E-early repair
• R-radial nerve
• V-vascularity
• E-end to end repair
GOOD NERVE

33. TREATMENT OPTIONS
• PARTIAL NEURORRHAPHY
• NEURORRHAPHY
• NERVE GRAFTING(sural nerve and saphaneous nerve)
• TENDON TRANSFERS

34. CARE OF PARALYSED PARTS
While recovery is awaited,
• the skin must be protected from friction damage and burns.
• The joints should be moved through their full range twice daily to prevent stiffness and minimize the
work required of muscles when they recover.
• SPLINTS-both dynamic and static alternatively

35. • A newly born child, delivered by full term vaginal delivery- shoulder presentation,birth weight-4 kg,born
to a gestational diabetes mother presented with deformity of left upper limb,with hand held in
pronation of forearm and hand held close to the body

40. • A patient with a past history of shoulder
dislocation,which was reduced in phc
and c/o weakness in abduction and loss
of sensory supply of lateral aspect of arm

41. • A patient came to jss hospital with c/o
inability to grip things and ride a
motor bike
• Past history of surgery to fracture of
humerus

43. CRUTCH PALSY

44. • A jss ug student residing in hostel came to opd with c/o weakness in fingers and deformity after socials
of their batch

45. RADIAL NERVE
• Wrist drop
• Fingerdrop
• Splints-cock up splint

46. • A software engineer presented with
tingling and numbness of radial side
of hand with thenar atrophy

47. MEDIAN NERVE
• Labourers hand
• Oschner clasp sign
• Ape thumb deformity
• Pen test
• Carpal tunnel syndrome
• Ok sign or kiloh nevin sign

53. ULNAR NERVE
• Musician nerve
• Card test
• Froments sign
• Ulnar paradox
• Claw hand