Different nerve injuries and regeneration

1. NERVE INJURY
CLASSIFICATION, NERVE
DEGENERATION,
REGENERATION AND
REPAIR TECHNIQUES
HANINE HASSAN

2. STRUCTURE OF
NEURON

4. CLASSIFICATION OF NERVE
INJURY
• Two different classifications are being
used to describe the nerve injuries
1. Proposed by SEDDON in 1943
2. Proposed by SUNDERLAND in 1951

5. SEEDON
CLASSIFICATION
• NEUROPRA
XIA
• AXONOTME
SIS
• NEUROTME
SIS

6. NEUROPRAXIA
• Minor contusion or compression of a
peripheral nerve with preservation of the
axis- cylinder but with possibly minor
edema or breakdown of a localized
segment of myelin sheath.
• Transmission of impulse is physiologically
interrupted for a period of time, but
recovery in a few days or weeks.
• Ex- Crutch palsy, Saturday night palsy

7. AXONOTMESIS
• More significant injury with breakdown of
the axon and distal wallerian degeration
but with preservation of the schwann cell
and endoneurial tubes.
• Spontaneous regeneration with
good functional recovery can be
expected.
• It is usually the result of a more severe
crush or contusion than neuroprexia.

8. NEUROTMESIS
• Severe injury with complete anatomical
severance of the nerve or extensive
avulsing or crush injury.
• The axon, schwann cell and endoneurial
tubes are completely disrupted.
• In this group, significant spontaneous
recovery cannot be expected.
• It usually occurs in gunshot or knife
injuries.

10. SUNDERLAND’s
CLASSIFICATION
• This is more rapidly applicable clinically,
with each degree of injury suggesting a
greater anatomical disruption with its
correspondingly altered prognosis.
• In this classification peripheral nerve
injuries are arranged in ascending order
of severity.
• Anatomically various degrees represent
injury to 1)myelin 2)axon 3)endoneurial
tube and its contents 4)perineurium
5)entire nerve trunk.

11. 1st degree
injury
• In this conduction the axon is
physiologically interrupted at the site of
injury but the axon is not disrupted.
• No wallerian degeneration.
• Recovery is spontaneous and usually
complete within a few days or weeks.
• Because there is neither axonal damage
nor regeneration, no Tinel sign is
present.

12. 2nd degree injury
• Disruption of the axon is evident, with
wallerian degeneration distal to the point of
injury and proximal degeneration for one or
more nodal segments.
• Integrity of the endoneurial tube is
maintained, providing a perfect anatomical
course for regeneration.
• Tinel sign can be followed along the course
of the nerve usually at the rate of 1 inch per
month, tracing the progression of
regeneration.
• Good functional return is achieved.

13. 3rd degree injury
• In this the axons and endoneurial tubes
are disrupted but the perineurium is
preserved.
• The result is disorganization resulting
from disruption of the endoneurial
tubes.
• Clinically, the neurological loss is
complete in most instances.
• Tinel sign is usually present.
• However complete return of neural function
does not occur, distinguishing this from 2nd
degree injury.

14. 4th degree injury
• In this the axon and endoneurium
and possibly some of the
perineurium are preserved, so
complete severance of the entire
trunk does not occur.
• No Tinel sign.
• Prognosis for significant return of useful
function is uniformly poor without
surgery.

15. 5th degree injury
• The nerve is completely transected,
resulting in a variable distance between
the neural stumps.
• Possibility of significant return of
function without appropriate surgery is
very remote.

16. 6th degree injury
• Also called as Mackinnon or mixed
injuries occur in which nerve trunk is
partially severed and the remaining part of
the trunk sustains, 4th degree, 3rd degree,
2nd degree, or rarely even 1st degree
injury.
• Recovery pattern is mixed depending on
the degree of injury to each portion of the
nerve.

17. Nerve Degeneration
• Any part of a neuron detached from
its nucleus degenerates and is
destroyed by phagocytosis.
• This process of degeneration distal to a
point of injury is called secondary or
wallerian degenetarion.
• The reaction proximal to the point of
detachment is called primary, traumatic
or retrograde degeneration.

18. • 1st 3 days- macrophagic changes
become apparent in axon
• After 3 days – distal segment becomes
fragmented and with subsequent fluid loss
the fragments begin to shrink and assume
a more oval or globular appearance.
• By 7th day macrophages have reached the
area in greater numbers,
• By 15 – 30 days clearing of axonal
debris is complete.

20. Nerve regeneration
• The onest of regeneration is
accompanied by changes in the cell body
• CHROMATOLYSIS with swelling
of the cytoplasm and eccentric
placement of the nucleus.
• The reaction within the cell body is evident
by day 7 and evidence of beginning
recovery is apparent after 4-6 weeks.

21. • The proximal segment of the axon
degenerates close to the injury for a short
distance, but growth starts as soon as
debris is removed by macrophages.
• Macrophages produce cytokines which
stimulate Schwann cells.
• In the nerve segment distal to the injury the
axon and myelin are completely removed by
the macrophages but not the connective
tissue.

22. • While these regressive changes take
place, Schwann cells proliferate within the
connective tissue sleeve, giving rise to
rows of cells that serve as guides for the
sprouting axons.
• Axonal sprouting may occur within 24hrs
after injury.

23. • Regeneration is successful only if the
endoneurial tube with its contained
Schwann cells has been uninterrupted by
the injury, the sprouts may pass readily
along their former courses and after
regenertaion the surviving cells innervate
their previous end organs.

24. • If the injury is severe enough to interrupt
the endoneurial tube with its with its
contained Schwann cells, the sprouts
may migrate aimlessly throughout the
damaged regions to form stump
NEUROMA.

25. Diagnostic tests
• ELECTRODIAGNOSTIC
STUDIES
1)NERVE CONDUCTION
VELOCITY
2)ELECTROMYOGRAPHY
• TINEL SIGN
• SWEAT TEST
• SKIN RESISTENCE TEST
• ELECTRICAL STIMULATION

26. Nerve conduction velocity
• A nerve conduction velocity test (NCV) is
an electrical test that is used to determine
the adequacy of the conduction of the
nerve impulse as it courses down a nerve.
This test is used to detect signs of nerve
injury.
• Stimulation of a peripheral nerve by an
electrode placed on the skin overlying
the nerve readily evokes a response
from the muscle innervated by that
nerve.

27. • This is useful shortly after an injury to provide
objective evidence of interference in nerve
conductivity but it is impossible to determine
the severity of the insult immediately after
injury.
• Immediately after injury, stimulation proximal
and distal to the insult may elicit a normal
response.
• As wallerian degeneration ensures within 5-10
days there is progressive reduction in the
amplitude and alteration in the configuration of
the evoked potentials.

29. EMG
• Electromyography (EMG) is a diagnostic
procedure to assess the health of muscles
and the nerve cells that control them
(motor neurons).
• Motor neurons transmit electrical signals
that cause muscles to contract. An EMG
translates these signals into graphs,
sounds or numerical values that a
specialist interprets.
• An EMG uses tiny devices called
electrodes to transmit or detect electrical
signals.

30. • During a needle EMG, a needle electrode
inserted directly into a muscle records the
electrical activity in that muscle.
• A nerve conduction study, another part of an
EMG, uses electrodes taped to the skin
(surface electrodes) to measure the speed
and strength of signals traveling between two
or more points.
• EMG results can reveal nerve dysfunction,
muscle dysfunction or problems with nerve-
to-muscle signal transmission

32. Tinel sign
• The Tinel sign is elicited by gentle percussion
by a finger or percussion hammer along the
course of an injured nerve.
• A transient tingling sensation should be felt by
the patient in the distribution of the injured nerve
rather than at the area percussed, and the
sensation should persist for several seconds
after stimulation.
• A positive Tinel sign is presumptive evidence
that regenerating axonal sprouts that have not
obtained complete myelinization are
progressing along the endoneurial tube.

33. Techniques of nerve repair
• ENDONEUROLYSIS (INTERNAL
NEUROLYSIS)
• NEURORRHAPHY
• NERVE GRAFTING

34. ENDONEUROLYSIS
(INTERNAL
NEUROLYSIS).
• It is an enoneurial exploration for assesing
the injury of fasciculli.
• If most of the fasciculli are intact and
can be seperated and traced through the
neuroma, nothing further should be
done.
• It stimulation fails to elicit a response, a
few if any intact fasciculli can be found,
resecting the neuroma and neurorraphy
are probably indicated.

35. NEURORRAPHY
• Primary neurorrhapy (<24 hrs)
• Delayed Primary neurorrhapy (2-18
days)
• Secondary neurorrhapy (<3 months)

36. TYPES
• EPINEURIAL NEURORRHAPHY
• PERINEURIAL NEURORRHAPHY
• EPIPERINEURIAL NEURORRHAPHY
All these come under primary
neurorrhaphy

37. EPINEURIAL
NEURORRHAPHY
Expose the nerve and dissect the redundent areolar
tissue from
epinuerium
Gently trim the nerve ends to identify good neural tissue
and locate
fescicles
Using the internal arrangement of fascicles and the vessels
on the
epinuerium determine the rotational arrangement
Place a 9-0 monofilament nylon suture through the
epineurium and
tie this stitch
Place sutures circumferentially around the cut surface,

39. PERINEURIAL
NEURORRHAPHY
• Same as Epineural Neurorrhaphy but in this
epineurium from the circumference
surrounding the groups of fascicles is also
removed.
• Attempt is made to match corresponding
groups of fascicles proximally and distally.
• After this nerve is repaired by suturing the
ends of the fascicles together with atleast 2
sutures placed through the perineurium at
180 degrees to each other.

41. EPIPERINEURIAL
NEURORRHAPHY
• This includes epineurium and
perineurium is useful in aligning large
groups of fascicles in larger nerves and
when nerves have been incompletely
transected.
• After aproximation of fascicles proximally
and distally repair individual fascicles in
central portion of nerve 1st by using 10-0
nylon suture
• Then approximate the fascicles and group of
fascicles that lie near the periphery of the
nerve by placing 9-0 nylon through the
epineurium and through the edge of the
perineurium.

43. • Post op care-
• The initial postoperative splinting is maintained for 3
weeks, during which time the patient is allowed
minimal active movement of the finger joints within the
limits of the splint.
• Suture removal done between 7-14th day.
• Four to 8 weeks after operation, removable plastic splints
are
used in reliable patients.
• Six to 12 weeks after surgery, careful attention should be
paid to the avoidance of fixed contracture .
• Eight to 12 weeks after surgery, progressive
strengthening
exercises are begun.

44. INTERFASCICULAR
GRAFTING
• This comes under secondary
neurorrhaphy
• Developed by MILLESI.
• He developed a technique of grafting
using multiple cuntaneous nerve grafts
that allow alignment of fascicles in
proximal and distal nerve stumps.

45. TECHNIQ
UE
Incise the epineurium proximal to the neuroma in normal appearing
tissue on the proximal stump and similarly towards the scared
distal stump
Identify major fascicle groups and follow them to the scar.
Transect thin fascile group there with microscissors and prepare both
ends Select a graft, expose and dissect the nerve graft
Keep it moist with ringer solution
Using diamond knife cut the nerve graft into sections 10% - 15% longer
than
the defect

46. Excise the redundent epineurial and areolar tissue from the graft
Place the nerve grafts between the proximal and distal nerve
stumps Use sketch of fascicles to determine where to attach the
graft at each end Obtain exact coaptation of the nerve graft to the
corresponding fascicle
groups
Suture the nerve graft at each end using 10-0 nylon placed through the
epineurium of graft and perineurium of one of the fascicle group
Close the skin carefully so that graft is not displaced by shearing forces
during
wound closure

47. Neuroma dissection before nerve grafting

48. Nerve grafts placed between nerve
ends
Nerve grafts sutured in
place
Technique of interfascicular nerve grafting

49. • Post op care-
• The part is immobilized for 8 to 10 days.
• Afterward the splint is removed, and free
motion of joints is allowed.
• Necrotic skin is debrided, and local flaps or free
skin grafts are used to cover a nerve graft that
may be exposed.
• Physical therapy with active and active-assisted
range- of-motion exercises is instituted under
supervision 2 weeks after nerve grafting.
• The progress of regeneration may be
followed by observing the Tinel sign.

50. Thank
you