Transcript PERIPHERAL NERVE INJURYIES MHD BASHAR ALBOSHI

PERIPHERAL NERVE
INJURIES
MHD BASHAR ALBOSHI
Tinel sign
Peripheral tingling or dysaesthesia provoked by percussing
the nerve
A positive Tinel sign is presumptive evidence that
regenerating axonal sprouts that have not obtained
complete myelinization are progressing along the
endoneurial tube.
@- neuropraxia(sunderland1) -------negative Tinel sign.
@- axonotmesis (sunderland2,3) -------positive Tinel sign.
(sunderland4-------- negative Tinel sign )
@- neurotmesis (sunderland 5) ------- negative Tinel sign.
The radial nerve, a continuation of the posterior cord of the brachial
.plexus, consists of fibers from C6, C7, and C8 and sometimes T1.
It is primarily a motor nerve that innervates the triceps, the
supinators of the forearm, and the extensors of the wrist,
fingers, and thumb.
This nerve is injured most often by:
-fractures of the humeral shaft.
-Gunshot wounds are the second most common cause of radial nerve injury.
Other causes include lacerations of the arm
and proximal forearm,
- injection injuries, - and prolonged local pressure.
-
Examination
The following muscles supplied by the radial
nerve can be tested accurately because their bellies
or tendons or both can be palpated:
- the triceps brachii,
- brachioradialis,
- extensors carpi radialis,
-extensor digitorum communis,
-extensor carpi ulnaris,
- abductor pollicis longus, and
- extensor pollicis longus.
@ Injury to this nerve results in inability to extend
the elbow or supinate the forearm and in a typical
wristdrop
Entrapment syndromes of the radial
nerve
@Nerve compression impaires epineural blood flow and axonal
conduction --------numbness, paraethesia ,weakness
-symptoms are intermittent,sometimes related to specific posture.
-prolong compression------segmental demyelination(tinel sign),target
muscle atrophy,nerve fibrosis.
-peripheral neuropathy(diabetes,alcoholism,discogenic root
compression..) +entrampment-----double-crush syndrome.
MRI,US--------exlude compression by soft-tissues mass(..ganglion).
-EMG,nerve conduction tests help to confirm the diagnosis, level of
compression, degree of nerve damage.( conduction is slowed,EMG
show abnormal wave or fibrillation in cases with severe nerve
damage).
- treatment: splint, corticosteroid injection ,operative decompression.
Entrapment syndromes of the radial nerve:
-may develop when the nerve or one of its branches is
compressed at some point along its course.
Two clinical patterns are encounters: 1- posterior interosseous syndrome
2- radial tunnel syndrome
posterior interosseous syndrome:
The posterior interosseous nerve may be compressed (at
proximal edge or within the substance of the supinator
muscle) by:
the fibrous arcade of Frohse(thickening of the proximal
edge of supinator),
- fracture-dislocations or dislocations of the elbow, -fractures of the forearm, -Volkmann ischemic contracture, - neoplasms, - enlarged bursae, -aneurysms, -rheumatoid synovitis of the elbow. -
-
Clinical features:
-
-pure motor disorder(weakness of metacarpophalangeal
extension affects first one or two and then all the digits.
-wrist extension is preserved( the nerves to extensor carpi
radialis longus and brachioradialis arise proximal to the
supinator)
-treatment:
condition does not resolve spontaneously within 3 months----------surgical exploration is warranted--------no
improvement by the end of a year and disabling--------tendon transfer.
radial tunnel syndrome
-entrapment of the posterior interosseous nerve cause chronic and refractory tennis elbow.
-can occur at four potentially compressive anatomical structures:
- the origin of the extensor carpi radialis brevis,
-adhesions about the radial head,
- the radial recurrent arterial fan,
-and the arcade of Frohse as the posterior
interosseous nerve enters the supinator.
- condition does not resolve-----------surgical exploration is warranted
(but the patient should be warned that surgery often fails to relieve the
symptoms.
@Lotem et al. found that when symptoms and signs develop only after muscular effort---------- spontaneous recovery can be
anticipated.
@Compression of the superficial radial nerve causes pain in the forearm
-
-
The ulnar nerve is composed of fibers from C8 and T1 coming
.from the medial cord of the brachial plexus
Injuries:
-When it is injured in the upper arm, other nerves or
the brachial artery because of their proximity also
may be injured.
-In the middle of the arm the ulnar nerve is relatively protected,.
-in the distal arm and at the elbow it often is injured by dislocations of the elbow and
supracondylar and condylar fractures.
-The nerve is injured most commonly in the distal
forearm and wrist; in these locations it may be
injured by gunshot wounds, lacerations, fractures,
or dislocations.
- In civilian life lacerations cause most of the injuries
.at the wrist
Postoperative ulnar nerve palsy:
- may result from either direct pressure on the
ulnar nerve at the elbow or prolonged
flexion of the elbow during surgery.
- The ulnar nerve is especially vulnerable to
compression when the forearm is allowed to
rest in pronation.
Examination
-Interrupting the ulnar nerve proximal to the elbow is
followed by paralysis of:
- the flexor carpi ulnaris, -the flexor profundus to the little and ring fingers, -the lumbricals of the same fingers, - all of the interossei, - the adductor of the thumb, - and all of the short muscles of the little finger. @Occasionally when a nerve is completely divided at this
level, the intrinsic muscles of the hand function normally
because of anomalous innervation of these muscles by the
.median nerve. (Martin- Gruber anastomosis).
Complete division of the ulnar nerve at the wrist
usually causes paralysis of all ulnar-innervated
intrinsic muscles unless an anatomical variation
connects the median and ulnar nerves in the palm
(Riche-Cannieu anastomosis).
- Usually when the nerve is divided at the wrist, only
the opponens pollicis, the lateral or superficial
head of the flexor pollicis brevis, and the lateral
two lumbricals remain functional
@In practice only three muscles tested
accurately:
-the flexor carpi ulnaris,
- the abductor digiti quinti, and
- the first dorsal interosseus
-The bellies or tendons (or both) of these
muscles may be easily palpated or seen
@Atrophy of the muscles supplied by the ulnar
nerve and clawing of the little and ring fingers
usually are confirmatory evidence of paralysis of
the muscles supplied by this nerve.
@ However, if the nerve has been injured proximal
to the elbow, clawing of these two fingers may be
absent because the flexor digitorum profundus to
the ring and little fingers also is denervated.
@The sensory examination usually is
straightforward, although anatomical variations
may cause confusing sensory findings. One need
examine only the middle and distal phalanges of
the little finger, which make up the autonomous
zone of the ulnar nerve .
cubital tunnel syndrome
compression neuropathy of the
ulnar nerve about the elbow with
no antecedent trauma.
- As the ulnar nerve enters the
cubital tunnel it is first bordered
by the medial epicondyle
anteriorly, then by the elbow
joint laterally, and finally by the
two heads of the flexor carpi
ulnaris medially.
-In other areas the nerve may be
compressed by ligaments,
neoplasms, rheumatoid
synovitis, aneurysms, vascular
thromboses, or anomalous
.muscles
@In patients suspected of having cubital tunnel syndrome:
-a positive percussion test( tinel,s sign) over the ulnar nerve at the level of the medial epicondyle
- and a positive elbow flexion test are strongly suggestive of a significant compressive neuropathy.
-negative test does not exclude the diagnosis. -in late cases there may be weakness of grip,slight clawing, intrinsic
muscle wasting and diminished sensibility in ulnar nerve
territory,weakness of abductor digiti minimi .
- Nerve conduction ----- slowing velocities across the elbow, although
normal velocities may be maintained during early involvement.
Electromyography ------ fibrillations in the ulnar innervated intrinsic
.muscles
-Conservative treatment for this syndrome should be attempted
such as modification of posture and splintage of elbow in midextension at night, before surgical treatment&
-
The surgical treatment of cubital tunnel
syndrome :&
-includes simple decompression,
medial epicondylectomy, -and anterior transposition of the ulnar nerve either into a subcutaneous,
intramuscular, or submuscular bed
@For a moderate degree ----excellent results
----with the submuscular technique.
Compression in Guyon,s canal:Ulnar nerve can be compressed as it
passes through Guyon,s canal at ulnar border of the wrist.
The exact level of compression determines whether symptoms are motor
or sensory or both.
Compression affects the deep branch of the nerve that supplies most of
the intrinsic muscles.
-A space-occupying lesion such as a ganglion from the triquentrohamate
joint is the most common cause to compression in this area.
- True or false aneurysm of the ulnar artery, thrombosis of the ulnar
artery, or fracture of the hamate with hemorrhage may be the cause
of pressure on the ulnar nerve.
@-Preservation of sensation in the dorsal branch of the ulnar nerve
suggest entrapment at the wrist rather than in the elbow.
further investigation should be considered: MRI--------------- diagnosis a ganglion CT----------------=
carpal fracture Doppler studies----- = ulnar artery aneurysm
-Treatment consists of removal of any ganglion or other cause of
Tardy ulnar nerve palsy
may develop after:
malunited fractures of the lateral humeral condyle in children, - displaced fractures of the medial humeral epicondyle, -dislocations of the elbow, - contusions of the nerve. - In malunion of the lateral humeral condyle, cubitus valgus develops; in this deformity the ulnar nerve is gradually stretched
and can become incompletely paralyzed.
-also may develop in patients who have a shallow ulnar groove on
the posterior aspect of the medial humeral epicondyle,.
- hypoplasia of the humeral trochlea, .
- an inadequate fibrous arch that normally keeps the nerve in the groove, resulting in recurrent subluxation or dislocation of the
.nerve.
The treatment for refractory tardy ulnar
nerve palsy
- may require.
.
Patients are instructed to avoid prolonged elbow
flexion in the workplace and are given elbow
extension splints for sleeping..
-
-Conservative treatment usually is attempted for a period of 3 months before surgical treatment is
considered(removal of the nerve from its groove, and
anterior transposition of the nerve to the flexor surface
of the elbow)
The median nerve, formed by the junction of the lateral and
medial cords of the brachial plexus in the axilla, is
composed of fibers from C6, C7, C8, and T1
Median nerve injuries :
-often result in painful neuromas and causalgia.
- From the sensory standpoint they are more disabling than injuries of
the ulnar nerve because they involve the digits used in fine
.volitional activity
-Median nerve injuries often are caused by lacerations, usually in the
forearm or wrist.
Sunderland pointed out that in: - the upper arm the nerve can be injured by relatively superficial lacerations, excessively tight tourniquets, and humeral fractures,
and when it is injured near the axilla, the ulnar and
musculocutaneous nerves and the brachial artery also are
commonly injured.
-
-At the elbow the nerve may be injured in supracondylar
.fractures and posterior dislocations of the elbow
-
Examination
The muscles of the forearm and hand
supplied by the median nerve that can be
tested with relative accuracy are:
-the pronator teres, - flexor carpi radialis, - flexor digitorum profundus (index), - flexor pollicis longus, - flexor digitorum sublimis, -and abductor pollicis brevis.
carpal tunnel syndrome (tardy
median palsy)
-results from compression of the median nerve
-within the carpal tunnel.
-8 times more common in women than in men.
-the usual age group is 40-50 years. -
DIAGNOSIS:
-Paresthesia over the sensory distribution of the median nerve is the most
frequent symptom;
-frequently causes the patient to awaken several hours after getting to
sleep with burning and numbness of the hand that is relieved by
exercise.
Atrophy to some degree of the median-innervated thenar muscles The Tinel sign ----------Positive -Phalen test (Acute flexion of the wrist for 60 seconds) in some but not all patients or strenuous use of the hand increases the paresthesia.
- Application of a blood pressure cuff on the upper arm sufficient to produce venous distention may initiate the symptoms
-in advanced cases there may be clumsiness and weakness, particularly
with tasks requiring fine manipulation such as fastening buttons.
-electrodiagnostic tests show slowing of nerve conduction across the
wrist.
Treatment:
In patients who have symptoms of carpal tunnel syndrome and
pronator teres syndrome,
-Light splints
-Corticosteroid injection into carpal canal-surgical
- If the nerve conduction test is positive ------conservative
-If the nerve conduction test is negative ------surgical. -
-
@The incision should be kept to the ulnar side of the thenar crease so as to be avoid accidental injury to the palmar
cutaneous and thenar motor branches of the median nerve.
@. For the anterior interosseous syndrome. If the onset of paralysis
has been spontaneous, the initial treatment is nonoperative.
Surgical exploration is indicated in the absence of clinical or
. electromyographic improvement after 12 weeks
the pronator syndrome
@Median nerve deficits, as seen in, may result from
compression of the nerve at
-the pronator teres(hypertrophy, fibrous bands ,a high origin)
the fibrous arch flexor digitorum sublimis. -
-the symptoms are similar to those of carpal tunnel
syndrome,although night pain is unusual and forearm pain
is more common.
-tinel,s sign---------------- positive.
Fhalen,s test--------------- negative.
-the symptoms can be provoked by flexion elbow with the
forearm supinated ,or resist forearm pronation with elbow
extended
The anterior interosseous
nerve syndrome
May compressed or entrapped by any of the following:
the tendinous origins of the flexor digitorum sublimis or the pronator
teres,
-variant muscles such as the palmaris profundus and flexor carpi radialis brevis,
- tendons from the flexor digitorum sublimis to the flexor pollicis longus,
- an accessory head of the flexor pollicis longus (Gantzer muscles), an
aberrant radial artery, thrombosis of the ulnar collateral vessels,
enlargement of the bicipital bursa, or a Volkmann ischemic
contracture.
.
-
-
-can cause varying signs and symptoms:
-Typically, the patient has pain in the proximal
forearm lasting for several hours
- is found to have weakness or paralysis of the flexor
pollicis longus, the flexor digitorum profundus to
the index and long fingers((unable to make OK
sign)), and the pronator quadratus.
-When the patient attempts to pinch, active flexion of
the distal phalanx of the index finger is impossible
-treatment: no improve after 3 months-------surgery.
PERIPHERAL
NERVE
INJURIES
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