covers all basics of peripheral nerve damage and concepts of management

1. Peripheral
Nerve
Injuries
Dr. YASIM
Dept. of Orthopaedics
LNH MAMC

6. Clefts of Schmidt -lantermann
 Incisures , oblique discontinuities in my myelin
 Function as an Interchange pathway between axon
internally and ECF externally.

7. Internal topography
Fascicular arrangement constantly change
the course

8.  Funiculi are numerous and small near joints except
ulnar nerve behind MEP and axillary nerve beneath
shoulder joint, where these two nerves frequently
composed of single funiculus.
 More epineurial tissue where cross joints
 Fibroblast, collagen fibre, mast cell common to all
three but mesothelial cells special feature of
perineurium.

10. Arteriae nervorum

11. Interfunicular arterioles

12. Nervi nervorum
 Originates from fibers in the nerve and form the
perivascular plexuses.
 Distributed to epi- , peri- , endonerium
 Sympathetic and sensory fibers

13. 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 explored

14. 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 1stto 4thdegree
injury.
Mixed recovery pattern depending on degree of
injury to each portion of nerve.

15. Lundborg
1988
Physiological
conduction
block
Myelin
damage
Axonal
damage
Axon
+
Endo
damage
Axon
+
Endo
+
Peri
damage
Axon
+
Endoneuriu
m
+
Perineurium
+
Epineurium
damage
Type Type
A B
Sunder
land
1951
I II III IV V
Seddon
1942
Neurapraxia
(Transient Block)
Axonotmesis
(Lesion in
Continuity)
Neurotmesis
(Division of a nerve)

17. Conduction block
 Arterial sleeve around nerve trunks blocks all fibers in
10 minutes ( Weiss and Davis 1943)
 Causes: compression/ traction/ ischemia / cold
 Differential sensitivity of motor and sensory fibers to
compression
 Damaged fibers more sensitive to ischemia than
normal fibers
 Large fibers more sensitive than fine fibers

18. Degeneration
 At site of injury:
 when sheath is preserved -crushed segment is
hyperaemic, endoneurial edema in 1-2 hours. By third day
schwann cell occupied tubes in crushed region and
regenerating axon sprouts .
 When sheath is ruptured- formation of retraction bulb.
Exudate btwn ends of fibre, bridging connective tissue
 Retrograde changes:
 When sheath intact- few mm
 When sheath ruptured – sevral cm nerve fibre reaction ,
nerve cell reaction, trans-synaptic neuronal reaction.

19.  Below site of injury: axon and myelin degenerate and
removed by phagocytosis, schwann cells proliferate
and the enodoneurial sheath is left encircling a column
of schwann cells.
 all traces of axon are lost by two weeks and precedes
degeneration of myelin
 Myelin fragments and paranodal and incisures act as
foci for physical distintegration by 8 th day and then
chemical degradation.
 Centrifugal failure: degeneration in terminal part of
intramuscular nerve fibre when more proximal part of
same fiber is normal.
 Nmj is affected before nerve and muscle
 Failure at nmj is delayed by 45 min per cm increase in
length of section of nerve

20.  If not reinnervated, or delayed too much the funiculi
are replaced with fibrous tissue
 Changes appear more rapidly in child
 Large myelinated fiber degenerate early
 greater the length of distal severed axon longer it will
survive

21. Regeneration
 Schwann cells forerunner of regenerative process
 Axon tip
 Initial delay: time to reach injured zone
 Scar delay: time taken by axon to cross injury zone
 Period of functional recovery: time for recovery in
sufficient number of fibers and appropriate
combinations
 Terminal delay: due to atrophic changes in skin, muscle
fibers
 Reinervation is precisely same if tube is intact, below
lesion earliest 4- 10 days from injury

22.  Axon tip shows amoeboid activity, growth cone 50 sprouts from
one
 Time axon reach tube will be free of debris
 Nerves retain capacity to sprout for several year from original
injury
 After suture repair axon crosses distaly in 3-20 days
 Single axon may branch and reinervate more than one tube.
 No increase in number of tubes in distal stump and preserves
original pattern of innervation
 Hoffman- tinel sign: radiating tingling sensation felt in cutaneous
distribution of injured nerve on light percussion


26. SystemicDiseases

27. IdiopathicNeuropathies

28. EntrapmentSyndromes

29. InfectiousCauses

30. 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

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

32. Diagnosis of Peripheral nerve
injuries
1. Motor:
– All muscles distal to the injury – paralyzed
& atonic
–
–
Atrophy : 50 -70 % in 1sttwo months
Striations & motor end plate configurations
retained for 12 – 18 months (critical limit
of delay)

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

34. (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

35. (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)

36. 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

37. • 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

38. Time of Surgery
• Primary repair : First 24 hours
• Delayed primary repair : First 1 – 18 days
• Secondary repair : 18 days- 3months

39. 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.

40. Skeletal stability
Healthy tissue bed
Healthy nerve ends
No undue tension
Adequate soft tissue coverage

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

45. Epineurial
Less exact
Simple
Group Fascicular
Better alignment
More dissection (scarring)
The functional results of group fascicular repair
has not been shown to be more superior than that
of epineurial repair.

47. Method of closing gap between nerve ends
1. Nerve grafting
2. Transposition
3. Bone resection
1. Mobilization ( critical nerve gap distance – value
of Grantham)
2. Positioning of extremity
–
–
Flex knee and elbow < 90°
Flex wrist < 40°

49. Motor
Proprioception
Touch
Temperature
Pain
Sympathetic
Recovery
Injury

50. Prognostic Factors of Outcomes
Patient
factor •Age
• 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

51. Evaluationof Patientwith
Neuropathy

52. History
• The diagnostic process begins with the physician
obtaining acareful history.
• The family, social, and occupational histories are
important for identifying familial occurrences or
toxic exposures.

53. History
KeyQuestions:
•Isthe onset sudden or gradual?
• Isthe progression rapid orslow?
• Isthe predominant manifestation sensory, motor, orboth?
•Isthe distribution focal or generalized, distal orproximal,
symmetric or asymmetric?
• Isthere autonomic involvement?
• Doesthe patient have any associateddiseases?

71. Relative predisposition to injury to peroneal
component than tibial
More superficial
Greater disability becoz of over stretched muscles
Poorer blood supply single funiculus with major nutrient
artery exposed on surface
Large and tighty packed funiculi with less connective tissue
Oblique course ,fixed at sciatic notch and neck of fibula

72. NERVE CRITICAL DELAY
High ulnar nerve lesions 9 months
Low ulnar nerve lesions 15 months
High median nerve lesions 9 months
Low median nerve lesions 12 months
Common peroneal nerve 12 months

74. EMG
 Can distinguish a recent from old injury in medico –
legal cases
 At initial post injury- normal or recruitment at this
point depends on injury pattern
 10 to 14 day- abnormal spontaneous rest potential ,
positive sharp waves in denervated myotome
 14 to 18 days- fibrillations appear
 3 months – polyphasic potentials / motor unit
potential increase progressively

80. Brachial plexus
 Erbs – C 5 6 with or without c7 dysfunction
 Extended elbow, adducted internally rotated
 If serratus ant, levator scapulae, rombiods gone
indicating lesion medial to dorsal scapular and long
thorasic
 Denervation potention in segmental paraspinous
muscles inervated by post rami
 Myelography- pseudo meningocele

81.  Klumpke-C8 T1 with or without C 7 dysfunction
 Intrinsic of hand / flexors of wrist and finger
 Horner syndrome -ptosis /anhydrosis /miosis
enopthalmos / loss of cilio spinal reflex

82. radial nerve
 In closed humeral fracture normal function may return
in 3-6 months
 In absence of nerve recovery and advancing tinel
exploration can be done after 3 months
 Tendon transfer can be done after 6 months

84. Median nerve
 Flexion of index and middle finger- side to side suture
with ulnar inervated fdp
 Fpl – brachioradilis / ECRL / ECU
 Thumb opposition- EIP

85. Ulnar nerve
restoration of intrinsic
If wrist extensors are strong to prevent flexion of wrist
and intrinsics are weak not paralyzed – bunnell transfer ( 4
fds, modified 1 ring finger fds split)
If wrist flexion is chronic habit- Riordan
Brand- ECRB/ 4 tailed free graft - volar to deep tansverse
metacarpal lig – lumbrical canal- radial side of extensor
apponeurosis except index finger difficult to re-educate
if wirst ext stronger than flex – brand – ECRL volarward 4
tail free graft

86.  If fds /wrist flex /ext not available- fowlers – EIP or
riordan modification of fowler- EIP + PL free plantaris
 If n0 muscle/ joint supple – zancolli capsulodeisis
 Bouvier test- if ext at ip present then static procedure
if ext not present dynamic procedure required
 Thumb adduction- omer- ring fds split brown- EIP in
palm near 3rd metacarpal

94. Thank You