types,classifications,investigations and surgical repair methods

1. NERVE INJURY CLASSIFICATION,
NERVE DEGENERATION,
REGENERATION AND
REPAIR TECHNIQUES
PRESENTER- MADHUKAR VANGA

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
• NEUROPRAXIA
• AXONOTMESIS
• NEUROTMESIS

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, attempting to
align appropriatly corresponding fascicles without suturing them.

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.
• Clinical evaluations of motor and sensory return are made
monthly

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. TECHNIQUE
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