Walk The Nerve.pdf

8/10/2019 Walk The Nerve.pdf

1/21

Aymeic

Lim,

Sandeep

Sebasfin

SUMMARY

A

brachial

plexus

injury

has

four

elements

akin

to

the four

dimensions

of

space:

breadth (no.

of

roots

involved),

length (level),

depth

(severity)

and

time:

rhe

two

basic

clinical

presentations

are

a

partial

lesion

(cs,ol

cs,o,z)

and

a

complete

lesion

(Cs,o,z,sTr)

The evolution

of

brachial injuries has three important milestones. These are

at

immediate presentation,

at

completion

of Wallerian

degeneration (three

weeks),

and

at onset

of

muscle

degeneration

(six

months)

The

history

obtained

from

the

patient

should

include

questions

relating

to the

energy

of

injury,

the

nature

of

the

pain,

the

presence

of

reinnervation,

and

the

social

circumstances.

The

examination

of

the

patient

is

targeted

to

determine

the

extent

of the

injury

(partial

or

complete);

the

level

of

the injury (condition

of

proximal

muscles);

the

severity

of

the

injury

(avulsion

or different

grades

of rupture);

and the

tirne

related

changes

(reinnervation

and

atrophy).

The

extent

of

injury

is

most

easily

determined

by

examining

sensory

dermatomes.

The

level

of injury

is

determined

by

testing

muscles.

The

signs

of

avulsion

include

absent

Serratus

anterior

and

rhomboid

function,

absent

diaphragmatic

function,

and

Horner's

syndrome.

An

assessment

of

the

Cz root

is

important

as

it influences

treatment

decisions.

This is

done

by

assessing

the

Cz sensory

dermatome

and wrist

extensor

function

(ECRB/

ECRL).

1.

2.

3.

4.

5.

6.

7"

8.

9.

A

progressive

Tinel's

sign

and

deep

muscle

pain

are indicators

of reinnervation.


2/21

l0,Regular

and

consistent

documentation

of

follow-up

visits is imperative.

A

good

.

standard

is

measuring

ffiryfiffi

(wiffrout

the

,plus/

minus

suffixes),

,W$:W

ffili*,

ar@r

ffi*w#.w{st

sffifrffi


3/21

INTRODUCTION

The

surgical treatment

of

brachial

plexus

injuries is relatively

straightfonrvard, once an

accurate

diagnosis

is made.

The

assessment

of

brachial

plexus

injuries is

fundamentally

clinical

and

investigations

serve

essentially to confirm

the

clinical

diagnosis.

These

injuries

therefore

need

a clinician familiar

with

the

anatomy. The

complexity

of

this anatomic

structure

and the

difficulty

in

remembering

how to examine

the'more

significant

of all

the

59 muscles

(this

includes

all

the

intrinsics and the

diaphragm)

supplied

by the

plexus

are

daunting

to

most

specialists in the fields of

hand,

orthopedic,

plastic

and

neurosurgery.

Most

surgeons are therefore reluctant to treat

brachial

plexus

injuries.

This

chapter aims

to make the assessment

of

these

injuries

less intimidating and to simplify

the

process of making an accurate clinical diagnosis.

All

that

is

required

are

three things;

a revision

of

the

anatomy,

the

technique

of

examining

specific muscles,

and

a chart to document

the

result of

the

clinical

examination.

There is

no simpler

place

to

revise

the anatomy than the

paper

by

George

Edwards.l(Fig.

1)

ITEP

f]

(Left

slde)

sTtP

#2

s;gt,

*l

cs

L

Add

3

branches

to

eoch

coro

Plus

the

long

Ltlorec

i

c

;rn:'?g,

l

hi

s

i,otal

s

l5

brancies,

1

\.\,,*

t

T1

Fig. 1: How

to draw

a

brachial

plexus

in

15

seconds

(or

less|


4/21

Muscle

examination

has

been

summarized

well

in

section

4

of Tubiana

et

al's

classic

'Examination

of

the

hand

and

wrist'.2

Most charts

3'4'5

are

box

based,

and

while

they

give

valuable

information

as to

the

root

levels

of

the

muscles

affected,

they

are

difftcult

to use

for

someone,

who

is not

familiar

with

brachial

plexus

anatomy.

We

use

a

chart

based

on the

branches

of

the

plexus

(Fig.

2 & Fig.

3).

BRACHIAL PLEXUS IHJUI(Y

MO'TOR ASSESSMENT C}IART

L*alorScapql*#

E

Rhombcidcr f,leior

m

E

Rhomboidls

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P*toralb Malor

fl

Pectoratts

Mlnor

ff

"e

"-,

' Corlchobrachialis

P

f-'l

,z

BlcePs

Erachile

El

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E

'/

E

suplnator*

E

BrachioadlalisrM

L:l

EeRL

r1

fl

TrictPs*ar

s

l--l

ECRB

oa

C5

c6

C7

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T1

s.ailr'tor f]

Acceisory:

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[=

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ECU

ua

D

EDco,

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ED$,u

E

APLt'''

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EPLrn

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EPB

'r'

,

[f

EIP

u"

Cf

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'"

fJ

FcR*

EpLra

D

Foszpr,,

Ef

FDs 3

o.r."r

CJ

Fos

4

o"'n

fI

Fos

5

or''o

E

FDP

2",-

fl

FDP3

rr.n

E

FPL,.*,

EPQrro

Ll

APB,',o

Cl

tumuricalels

'h'

FCU

fJ

r.s

FOp

4

fl

u.E

FDp

5

f:

rqrLumb:ical

EJ

ur

Oorsrl

ln&roseel

E3

iit

Pak il

lnE'olsel

E

mAp

fl

Another

concept

we

have

found

useful,

when

trying

to

describe

a brachial

plexus

injury

is to

relate

it to

the

four

dimensions

of

space.6

The first

dimension

to

consider

is

the

breadth

of the

lesion,

which

indicates

the

number

of

roots

involved.

The

next

dimension

is length,

which

corresponds

to

the level

of injury

indicating

whether

the

injury

occurred

which

refers


5/21

BRACHIAL

PLEXUS INJURY

SENSATION

ASSESSMENT CHART

R/L

w"

ffio

Daile:..,.,..'

Examiner:

..

Fio.

3:

Chart

for

sensorv

assessment

of

brachial

plexus

iniuries

to

the severity

of

the injury,

and this

is

understood

in terms of

the

grades

of

nerve injury

as classified

by

Sunderland.T Time,

the fourth

dimension

unmasks

the

extent

of the

injury.

lt also

altows

recovery

of

partially

injured

roots and

can reveal reconstructive

options.

r-

t#

S0

fllilfiillillfi

o

l:;:i;;;:ll::l s.rf

FI.lT::l

s+

i:3-iJ

"r-i45---

le--.**

-H*--*

t-a-F.*5ts

adq**b.E

kr*--F-

*h--r-

*-4r&c

f&td.ikrr*h

b-J+bi.


6/21


7/21

3.

The

next

critical

stage is

at.,:6:nwqths

and

beyond.

This

indicates

the

end,:of

the

d&n

period'1o

for

primary

brachial

plexus

surgery

(primary

repair/

grafting/

nerve

transfers

etc.)

and

the key

biological

event

is

muscte

degeneration.ll

At

this

stage,

neurstiga'Ssn,'is

usually

no

longer indicated, exeept

for

pain,

and free

musele

tranefers

are the

chosen

option.


8/21

DIAGNOSIS

History:

There are four main

points

to

be acquired.

1.

The energy and thus

the

severity

of

the

injury

2. The

nature

and

the

radiation of the

pain

3.

The

presence

of reinnervation

4. The

patient's

social

circumstances

The objective

of

determining

the events

surrounding

the accident

is

to

establish the

depth or

severity

of

the

injury.

ln

developing nations,

the

motorcycle

is the cause

of

a

brachial

plexus

injury

in 82%

of

cases,

as

in

Songcharoen's

series

of 520

cases.12

In

developed countries,

the

causes

are

more

varied and

sports

related

injuries

are

more

common.

'Burners'

or acute traction

injuries

caused

by

stretching

of the

upper

plexus

roots

when

tackling

or falling

affects

up to

50% of

football

players.l3

A

motorcycle

accident

at speed on

a highway

is more

likely to cause

a

severe

nerve

lesion than

a

scooter collision

with a

pedestrian

on a city

road.

The energy

transfer

in an

injured

football

player

would

be even

lesser.

The

presence

of associated

injuries

suggests

high energy

trauma.

Associated

injuries

can

be

divided

into two

groups:

peripheral

and

central.

Peripheral injuries

include

limb

fractures,

rib fractures

and hemothorax.

Central injuries

are

neurological.

They range

from spinal'cord

injuries

to

cranial

hematomas.

They

may resuit

from avulsion

of

the

ventral and

dorsal rami

of the

roots

of

the

spinal nerves.

The

pain

that

patients

feel is

neuralgic and

is

caused

by

interruption of the

nerve.

lt

is

commonly

described

as burning

or

stabbing and

distresses them

greatly.

Severe

pain

is

often a sign

of avulsion.la Patients can be surprisingly

specific about the

radiation of

this

pain

and can even refer

it

to

a

dermatomal

distribution.

This

symptom

is an

aecurate

indicator

of

the

breadth of the

lesion,

or the root

involvement. A Cs,

Ce avulsion

injury

will

manifest

in

neuralgic

pain

in

the

lateral aspect of

the

arm,

forearm and thumb.

The

absence of

pain

is

also

important and

when it

associated

with

loss of function, it implies

reinnervation.


9/21

It is important

to

ask

the

patient

regarding

any evidence

of

reinnervation.

The

patient

wilt

be

able

to

tell

you

about

a

twitch

in

a

muscle

before

you

can see it

and assign

a

grade

I

power

to it.

Similarly

it

helps

to

teach a

patient

about

Tinel's

sign. This

is something

that

lhey

can easily

monitor

and

involves

them

and

motivates them

in

the

process

of

recovery.

Finally,

the

surgeon

must try

to understand

the

patient

and

evaluate

their social support.

The

patient

has

just

sustained

a

devastating

injury

and

the toss of a limb.

Their

prognosis

is

based

not

just

on

the severity

of

injury,

but on

the

patient's

outook

and

his/

her social

circumstances.

One needs

to

assess

the

patient's

motivation,

their family

support

and

job/

financial

constraints.

Much

of the

pre

and

post-operative

care of

patients

with

brachial plexus injuries involves practicat

and

social counseling

and

the

management

of

pain.


10/21

Examination:

lt is

at

this stage

that the

physician

confirms his

diagnosis

and

a treatment

plan.

The

clinical

examination

of a

patient

with a

brachial

plexus

injury

targeted

towards

answering

four

questions.

What

is

the extent

of

the injury?

(ls

it

partial

or

complete?)

what

is

the level

of the injury?

(ls

the

proximal

musculature

preserved?)

What

is

the

severity

of the injury?

(ls

it

an

avulsion or

a

rupture?)

What

are the

time related

changes?

(Has

there

been any recovery?)

sequence

of thought

is repeated

through

two

cycles,

once during the

proeess

of

and again

during muscle

examination.

lf a

patient presents

with

a flail

upper limb, winging

of

the scapula and,

a

sign,

it

is evident that he

has

an avulsion injury of all the roots

(Fig.

4A &

B).


11/21

Wth

the

patient's

torso

completely

exposed,

the

examiner

looks

for

wasting,

the rnuscle

desolation

wrought

by

the

nerye

injury.

He

assesses

the

extent

by

systematically

,scanningmyotomalsectors.The*essectorincludes#Wand

theffi.

the$6Bi$dbro,'i,

th.W

an##

the

.l@S

when

the hand

is flail,

and

digital

flexor

or intrinsic

function

is

absent.

Skip

lesions

in

plexus

injuries

almost

never ocour

and

sparing of

a

myotomal

sector

only

occurs

at

the

cranial

or

caudal

end of

the

roots.

lt

is

difficult

to

precisely

define

the

level

of

the

lesion

by

inspection.

However

the

presence

of

proximal

musculature

is

a

good

indicator

that

the lesion

is

at

or

beyond

the cords.

It

is important

to

understand

that a nerve

root

avulsion

does

not

indicate

just

the

level

of

the

injury,

but also the

severity.

This

has profound

implications for

reconstruction, both

intermsoftimingandoptionS.Wr.:[E@.](gtg6:ffiiffiis

manifested

irffiFIa

while

avulsion

of

thG&rt&f

ffi.isrevealednyaffi.Anotherindicatorofavulsioniscervieal

scoliosis (Fig.

48),

following

disruption

of

the

posterior

branches of

the spinal nerve

going

to

the cervical

paravertebral

muscles.ls

The moisture

of the skin

can also

give

useful

information

about

the lesion.

Dry

skin

in

an anaesthetic area

suggests

a

post-

ganglionic

lesion;

on

the

contrary,

a normal

moist skin

suggests

a

pre-ganglionic

lesion.

Sliding

a

plastic

pen

over

the

skin

of the affected

limb

and

comparing it to

the

normal

side

can be

used

to test

sweating

function

of the

skin.16

Other indicators

of a severe

injury

are

associated

injuries

and

scars.

Finally,

the

way

the

patient

is

able

to cope with

the

paralysis,

take on

or

off hisi

her

clothes

and deal with

normal

activities

is

important

to

note.

The

older

the lesion,

the

easier it

is

to make a

complete

diagnosis

just

by

inspecting

the

patient.

Palpation:

The

examination

should

always

start

by testing

dermatomes.

This

is

the

easiest

way

to

determine

the

extent

of the

lesion

and

gives

important

and

reliable

information.ThekeytorememberingthedermatomalmapisthattlWffiis

suppliedbythffiTherestofthemapcanthenbeworkedoutquite

logically

by working

ones

way,

cranially

and caudallym

supplies tndilE&ilre

ffinoffi&eupplies

tnffi

an@u

themt

(Fis.


12/21

2B). There

are four notes of caution. The medial aspect

of

the

arm

is supplied

by

T2,

the

inter-costobrachial

nerye.

The index

is

usually

supplied

by Cz,

as donor morbidity

from

cross

Cz

transfers

has demonstrated.lT

lncomplete

nerve lesions

or lesions

affecting

C5

may

not

give

complete

anesthesia

of the dermatome.

Over

time, adjacent

neurotization

may

blur the

edges

of the

dermatomal

territories

Once

the extent

of the injury

has

been

determined,

the

next

step

is

to

determine

the

level

of

the

injury.

This is

done

by muscle

examination.

Narakas

describes

five

levels:

the

roots;

the anterior

branches

of the

spinal nerves,

the

primary

trunks,

the

secondary

cords

and

the

peripheral

nerves.18

More

practically,

there are two

important

levels:

avulsionsandruptureS.-canonlybewhilewith

-he

option

of

There

are many muscles

to test

and all muscles

have

more

than one

root

origin.le

A consistent

sequence

of

examination

is

thus necessary.

lntuitively,

it

makes sense

to

'walk'the

nerves

(Fig.

S).

Fiq.

5:Walkinq

the nerves


13/21

This

is only

possible

if

there

is

a clear

picture

of

the anatomy

in

one's

head.

ln

the

beginning,

it is

always

helpful

to

have

a

diagram

at

hand,

while

recording

the findings

in

a chart

as in

Fig.

2A.

It

is important

to

record

the

motor

power

accurately"

The

MRC

system

of

grading

motor

and

sensory

function

is

standard"

lt

is

logical

to

begin

by

'walking'

the

es root, the

most

cranial

and

proximal

part

of

the

plexus.

The

first

branch

is the

phrenic

nerve"

The

clinical

test

for a

raised

hemidiaphragm'is

percussion

of the

chest wall

in inspiration

and

expiration,

There

should

be an

additional

two intercostal

spaces of

resonance

with

inspiration.

This

test

is

hard

to

administer

accurately,

and

a

quick

glance

at

the chest

X-

ray will

usually

give

the

required

information

accurately

and

more

efficiently"

(Fig"

6)

Fiq.6:

CXR

to show

phrenic

nerue

pals:t

The

next

branch

of

Cs is

the

long

thoracic

nerve,

which

also receives

contributions from

C6

and

Cz.

The

branches

arise

very

proximal,

near

the foramina"

Paralysis

or weakness

of

the

.serratus

anterior,

supplied

by this

nerye

is

strongly

indicative

of an

avulsion of

one

or

all

of the

roots

of supply.

lt

is impossible

to

test the

serratus

anterior in

the

conventional

manner,

when

the

deltoid

and

biceps

are also

paralysed

as is often

the

case.

To overcome

this,

one has

to use

a modified

test.

The

examiner

holds

the inferior


14/21

angle

of the

scapula

between

the thumb and

index

finger

(Fig.

7)

and

the

patient

asked

to

lie

supine

with

his

arms

outstretched

(forurard

flexion

at 90")" The

patient

asked move

his arms forurard

and

the

examiner

resists using his

other hand"

Fiq.7. Assessment

o'f-Se atus anterior Fjg1..Spapular

winqinq

in

serratu$

palsv(A)

and trapezius

palsv

(B)

The

examiner feels

for a true

movement of

protraction,

and

in

a

patient

with an intact

serratus,

the

examiner

will

be unable to keep his

grip

on

the

inferior

angle

of the

scapula. The force of

the

muscle is evaluated

as M5

(normal

resistance),

[ti14

(reduced

resistance,

but with

full

movement), and M3

(no

resistance, but with movement against

gravity).

The

patient

is evaluated in

the sitting/ standing

position

(to

eliminate

gravity)

to

assess

M2. ln

case,

there

is no movement,

but only

a

palpable

contraction,

it

is

grade

M1

and M0

is total

palsy.

There are

many subtleties

to

winging,

and

paralysis

of the

trapezius can also

cause winging"

ln a

serratus

anterior

palsy,

the inferior

angle of the

scapula

is

separated

from

the thorax and

pulled

backwards

to the spine.

On the other

hand,

in trapezius

palsy,

the scapula

moves

outwards

and forwards"20 When

both

muscles

are

paralysed,

the entire

medial border

is lifted

up.

(Fig.

8)

IS

is


15/21

The

next

branch

is

the dorsal

scapular

nerve

and

this innervates

the

rhomboids and

the

levator

scapula.

Both

the C+

and C5

ventral

primary

rami contribute

towards

this nerve"

The

rhomboid

major

arises from

the

spinous

processes

of

the Tz to Ts

vertebrae

and it

inserts

on

the medial

border

of the

scapula,

from

about the

level of the seapular

spine

to

the

scapula's

inferior

angle"

lt is a

diffieult

muscle

to test

as it lies deep

to the trapezius.

It is important

to

note that

it

is

an antagonist

of

the

serratus

anterior

and therefore

best

tested

by resisting

retraction

of

the scapula.

The

patient

is

made

to

lie

prone

with his

arm

in

internal

rotation.

The

examiner's

thumb

is

placed

on

the

medial

border

of

the

scapula

at the

level

of the

spine. The

patient

is then

asked

to

push

his

arml

shoulder

backward

with

the

examiner

offering resistance

using

his sther

hand. The

examiners

thumb can feel

the

contraction

of the

rhomboids

and

the

scapula

slips

medially

under

the thumb.

(Fig.

9A)

This can

be compared

to the other

side. The strength

is evaluated

as

Ms

(normal)

(Fig.9A),

M4

(full

movement,

but less resistance),

and

M3

(no

resistance,

but

movement

against

gravity)"

M2

indicates movement with

the

patient

sitting

or

standing

(Fig"

9B),

M1

indicates

palpable

contraction

without any

visible

movement,

while

M0 denotes

the

absence of

any

palpable

eontraction,20

F iq. ?AJ_SSa

ss m

e

n

t o

flh

o

m

b o

id

s

qradeQl4/L

Fiq.

9B:

Assessment

of rhomboids

qragle

112


16/21

The serratus anterior and rhomboids

are

diffieult muscles to test. The

most

direct way

of

testing

these or any

muscle is

to

grade

the effect that they have

on the bone upon which

they

are inserted.

Thus,

just

as

triceps function is

assessed by its effect

on the ulna,

the

serratus

anterior

and

rhomboid

functioRs

are

best

assessed

by their effeet

on

the

scapula

Proceeding

distally,

the

Cs root

joins

the

Co root

to

form

the

upper trunk and

the first

branch

from

the

upper trunk is

the

suprascapular

nerve.

It

receives eontributions fronn

both roots, and

supplies

the

supraspinatus,

and

infraspinatus.

lt is

not

uncommon for

this

nerve

to

be injured at

hivo

levels2l

and at this stage

it

costs nothing to

palpate

the

nerve

from Erb's

point

(junction

of

Cs and Co) to the scapular

notch.

Abnormal

tenderness

or

a

positive

Tinel's

sign

at

the

notch would

be an indication for distal

exploration.

The

supraspinatus

initiates abduction.

lt is thus

tested

by

preventing

the

initiation

of abduction. The difficulty in examining

the

supraspinatus lies in

the

fact that

its

location

and function are masked

by hruo

large

muscles, the deltoid

and the

trapezius.

Flq.

7

0.

Assesszeof

of

suprasBlnafus


17/21

The

trapezius

overlies

it,

but

supraspinatus

contraction

may

be

recognized

by

feeling

the

muscle

just

superior

to the

spine

of

the scapula,

or by

asking the

patient

to

abduct

with

the

trapezius

contracting"

The

examiner

will

be

able to

feel

an additional

contraction

beneath the

hardened

trapezius.

The

patient

is asked

to stand

with his

arms internally

rotated

and attempt

abduction.

The

examiner

palpates

the

supraspinatus

with

one hand

and

offers

resistance

with

the

other hand.

(Fig.

10) The

strength

is

evaluated

as

IVIS

(normal,

abduction

to

70"

with

strong

resistance),

M4

(full

movement,

but

less

resistanee),

and

M3

(no

resistance,

but movement

against

gravity).

M2 indieates

msvement

with

the

patient

supine,

M1

indieates

palpable

eontraction

without

any visible

movement,

while

M0 denotes

the

absence

of any

palpable

eontraction"20

The

infraspinatus

rnuscle

is the

most

powerful

external

rotator of

the

humerus,

and

is easier

to examine"

The

only additional

point

being thatwith

biceps

paralysis

present,

the elbow

and

forearm

must

be

supported before

asking

the

patient

to externally rotate"

From

the

upper trunk,

the

examiner

may

take

one of two

paths

leading

to

the

lateral

cord,

or more

intuitively,

to

the

posterior

cord where

he

or

she

may complete the

examination

of

the

shoulder abductors,

namely

the

deltoid.

The

anterior, middle, and

posterior

portions

of

the

deltoid

have

to be

tested separately.

Fiq. 11:

Testing

anterior

(N:

middle

(H

&

oosterior

le)Lcortiqn

gf

deltoid

The key

to

testing

the

deltoid

is to

eliminate

the

action

of

the

supraspinatus" Thus

testing

is

started

with the

patient

standing,

arm

in

g0'abduction,

and internally rotate*

(palm

downwards)"

The

anterior

portion

tested

with

the

finger

pointing

forward

(Fig.


18/21

11A),

the

middle

portion

with the

fingers pointing

laterally (Fig. 118),

and

the

posterior

portion

with

the

patient

lying

prone

with

the forearm

hanging down

(Fig.

11e). The

examiner

palpates

the

respeetive

portions

of the deltoid with

one hand,

and offers

resistance

with the

other hand"

The strength is

evaluated

as

IMS

(normal,

abduetion to

90"

with

strong

resistanee

applied

to

the forearm), I'14

(full

movement,

but

less

resistance),

and

M3

(no

resistance,

but

rnovement

against

gravity).

fu/z, fi/1

and NIO

power

is

evaluated

with

the

patient

lying

on his

side for the anterior

portion,

supine

for

the

middle

portion,

and

the

examiner supporting

the

arm

for"

the

posterior

portion"

Reinneruation occurs flrst

in

the posterior portion,

then

the lateral

and

finally the anterior

portion"2o

The

teres minor

is also innervated by

the axillary nerve,

produees

external

rotation

of the humerus,

is tested along with

the

infraspinatus,

and is

palpated

just

beneath

the

posterior

portion

of the deltoid"

The

posterior

cord

examination

is

eompleted

by

testing

the

teres

major and the

latissimus

dorsi, adductors

and internal rotators of the arm"

The

teres major

is

tested

in

the

sittingl

standing

position

by

asking

the

patient

to adduet and internally

rotate

the

arm.

lt

is

easy

to

test, when

the

other

internal

rotators are

paralyzed,

but

mueh

more

difficult

when

they are

active" The latissimus

dorsi

is

tested

with

the

patient

in

the

prone

position

and his

palm

facing

backwards"

He is asked

to

pull

his arm'baekwards. The

integrity

of the other

cords is verified

by testing

the

pectoralis

major"

,

fesfino

lower


19/21

draw

th

and

the

This

is

tested

by

asking

the

patient

to

a the

the

B&C)

TheCs

is

left

with

fII

This is

easily

done

by asking

the

patient

to

assume the

body

building

pose

of

Iffiandthe

its

upper

part

and

its

lower

part.

(Fig.

12A,

completed,

the

examiner

root

and cord

examinations

having

been

only.

examined in turn.

'

Siqns

of

reinnervation:

lt

is

the

passage

of

time,

more

than

the

most

exhaustive

examination

or

the

most

sensitive

investigation

that

confirms the

extent, level

and the

severity

of a

lesion.

Evidence

of

steady

recovery

is an

excellent

prognostic

sign,

while

a

silent

and

flail

arm is

the

expression

of

a

deep and

an extensive injury.

The retum

of

nptor

and sensory

function

are

the conclusion

of

reinnervation.

This is

preceded

by two

important

signs

that are

particularly

useful

when

assessing return

of

function

after

neurotization.

The

first is Tinel's sign.

This

was described

separately

by

Tinel,

and

Hoffman

in

1915.22

Tinel's

sign

is elicited

by

lightly

percussing

along

the

course

of the

affected

nerve

from

distal

to

proximal.

When

the finger

percusses

over

the

zone.of

regenr:ating fibers

the

patient

will

announce

the

sensation

of

pins

and

needles,

which may be

quite

painful,

into

the

cutaneous

distribution

of

the

nerye,

The

advance

of the

regenerating

axons

down

the nerve

can

be followed

by studying

the advance

of

the

Tinel's

sign. There is an

element

of

unreliability

as some

of these

regenerating

axons

are not on their way

to any

targe,t.

ln

general,

a strongly

positive

Tinel

sign over

a

lesion

soon after

injury indicates

.'*;rrupture

or

severance"

lf a

nerve repair

is

going

to

be

successful,

the

centrifugally

nrcving

Tinel sign

is

persistently

stronger

than

that

at the suture line,

and

if

the repair

is

going

to

fail,

the Tinel

sign at

the suture

line

remains

stronger

than

that at the

growing

point.

A

failure

of

distal

progression

of

the Tinel

sign in

a closed lesion

indicates rupture

or

other

lesion impeding

regeneration.23

Although

the

Tinel's

sign

is difficult

to

interpret

in

Brachial

plexus

lesions,

Landi

et al2a have

enumerated

the value

of

Tinel's

as

follows


20/21

No

response

at all implies preganglionic damage to the injured root

assessed.

Local pain

implies

that

there

is

an

underlying

cervical plexus

lesion

which

is

recovering,

or

that

there

is

residual

contrast

medium

in

a

pseudomeningocoele.

Pure

Tinel's

sign

means

that

that

the

lesion

is

in

anatomic

continuity

and

sequential

recordings

can

demonstrate

progression

of

recovery.

Roots

Cs

and

C6

are

the

most

superficial

and

Tinel's

sign

can

easily

be

elicited.

Cz,

Ca

& Tr

are

deeper

and

difficult

to

assess.

4'

The

neuroma

sign

is

positive

when

pain

is

elicited

in

the

distribution

of

the

nerve

when

tapped.

This

sign

means

disruption

of continuity

of

the

whole

nerve.

The

second

and less

well

recognized

is

deep

muscle

pain.

This

pain

is

elicited

by

pinching

the

muscle

that

is

being

examined.

The

pain

felt

is

distinctive

and

is

different

from

a

skin

sensation.

lt

is

feels

like

a

deep

and

acid

ache

and

always

produces

a

characteristic

wince

in

the

patient.

This

pain

can

be

differentiated

by

doing

a

similar

squeeze

on

the

normal

side.

lt is

not

dissimilar

to

the

pain

experienced

when

having

a

muscle

cramp. Early on,

it

may

be referred

to

the

neurotizing

area,

i.e.

chest

wall

after

intercostals

to

biceps

transfer.

lt

follows

a

Tinel's

sign

that

has

progressed

into

a muscle

and

appears

before

evidence

of

grade

1

power.

There

are

during

the

t

of

nerve

and

muscle

-ln

the

first

phase,

one

follows

the

Tinel's

sign

down

the

course

of

a

nerve,

into

the

muscle'

ln

the

second

phase,

once

the

axons

reach

the

muscle,

one

can

elicit

deep

muscle

pain'

The

third

phase

is

observing

for

the

various grades

of

the

MRC

score.

For

the

purposes

of documenting

recovery

of

a

lesion,

spontaneous

or after

nerve transfer

or

a

functional

muscle

reconstruction,

it

is

better

to

use

more

precise

measures.

These

are'

for

the

shoulder,

scapulohumeral

angle;

for

the

elbow,

kilogram

weights

and

for

the

wrist

and

fingers,

ranges

of

motion.

lRventory

of

reconstructive

options:

A final

part

of

the

examination

is

the

cataloguing

of

reconstructive

options"

Scars

in

the

intercostal

spaces

from

chest

tube

insertion

would

preclude

the

use

of

that

intercostal

nerye

for

neurotization,

A

well

recovered

latissimus

1.

2_

3.


21/21

dorsi

or

a

good

long

head

of

triceps

give

options

for

the

reconstruction

of

elbow

flexion.2s

The

best

reconstruction

for

elbow

flexion

is

the

Oberlin nerve

transfer,26

lt

gives

the

best

results,

has

the

least

morbidity

and

can

even

be

done

as a

day

surgery

procedure.

However,

the

presence

of

a

good

ulnar nerve

is

required

before an

Oberlin

tansfer

can be

considered.

This

is

most

reliable

when

the

cz

root is

intact,

as

patients

with

avulsion

of

Cs,o,z

ore likely

to

present

with

grade

2

or

grade

3 lesion

of

the CaTr

roots.27

lt

is

thus important

to

ascertain

the

quality

of the

Cz

root. First

check

the Cz

sensory

dermatome

by

assessing

the

sensation

in

the

middle

finger.

Next

check

the Cz

myotome.

This

is

made

difficult

as

there

are

more

than

20

muscles

with

shared

innervations

from

the

Cz

root.

The

most

reliable

way

of

confirming

an intact

Cz root

is to

look

at

proximally

innervated

muscles,

which

are

not innervated

beyond

the

Co

root.

These

are

the

deltoid,

biceps

and

brachioradialis.

lf

these

are

absent in

the

presence

of

wrist

extensors (ECRL/

ECRB),

then

the

partial

lesion

that is

present

probably

involves

only

Cs and

Cs roots.

If

these

are

absent

along

with

absence

of wrist

extensors,

then

Cz

root

is

likely

to

be involved

and

one

should

be

cautious

about

using

the

Oberlin

procedure.

Measurino

results:

Accuracy

and reproducibility

of

results

is vital.

Despite

all

its

drawbacks,

the

MRC

classification

of

muscle

recovery

and

sensory

loss

is

standard. lts

primary

drawback

is its

lack

of

sensitivity.

This

has been

eloquently

elaborated

by

Narakas

'the

power

of

a

muscle

to

lift the

arm

against

gravity

is much

rhore

than

that

to

move

a finger'.

However

in

the

absence

of a

better

system,

one must

use the

MRC

system

in a

consistent

manner.

There

is

no

place

for

the

commonly

used

plus

or

minus

suffixes

as

they

are

not

reproducible

and

vary

widely

from

examiner

to

examiner,

especially

in

the

rather

subjective

region

of

power

grip

from

3+

to

4-,

lf the

suffix

is being

used

to log

an

improvement

in

muscle

power,

a note

can

be

made

in

the

records.

This

also

allows

for

an

accurate

assessment

of reinnervation

and

available

reconstructive

options.

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