6. Clefts of Schmidt -lantermann
Incisures , oblique discontinuities in my myelin
Function as an Interchange pathway between axon
internally and ECF externally.
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.
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.
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
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.
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.
46.
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°
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
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?
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
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
73.
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
75.
76.
77.
78.
79.
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
83.
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