basic science art & nerve

8/18/2019 Basic Science ART & Nerve

1/56

Basic ScienceBasic Science

ConferenceConference

Nerves & ArteriesNerves & Arteries


2/56

OutlineOutline

Peripheral nerves: histology &physiology

Peripheral nerve injury &regeneration

NCV / EMG basics

Peripheral compression neuropathies

Vascular disorders


3/56

Peripheral NervePeripheral Nerve

HistologyHistologyNeuron:

! Cell "ody

#! $endrite

%! 'on

(! Presynaptic

terminal


4/56


HistologyHistologySchwann Cells (PNS)

)urround cell body &a'ons

Provide support andnutrition* maintainhomeostasis* +ormmyelin* and assist in

signal transduction Ma,e myelin


5/56

PhysiologyPhysiology

Electrical andchemical signals

Resting Potential

-normal. -0 to-10mV* maintained by

Na+/K+ pump

Action Potential

-depolari2ationbeyond thresholdtransmits signalrapidly


6/56


Cross Sectional AnatoyCross Sectional Anatoy!pineuriu Encompasses nerve

and runs bet3een

+ascicles VascularPerineuriu 4ayer that covers

individual +ascicles

5ensile strength!n"oneuriu 6nner most collagenous

matri' that surroundsa'ons 3ithin +ascicles

Nourish & protecta'ons


7/56

#rauatic Nerve $n%ury#rauatic Nerve $n%ury

ClassicationClassication7(%: Seddon

Neuropra'ia

'onotmesis Neurotmesis

7: Sunderland Type I- V


8/56


9/56


ClassicationClassication'st egree (Neuropraia) Interruption of

conduction at site o+ injury 'on preserved No 3allerian

degeneration Motor 8bers more

susceptible to injury

than sensory 8bers


10/56


ClassicationClassication'st egree (Neuropraia) 4arge myelinated 8bers more

susceptible than 8ne or nonmyelinated8bers Electrophysiologic )tudies

9 NCV slo3ing or complete conduction bloc,9 ibrillation potentials9 Positive sharp 3aves


11/56


ClassicationClassication'st egree (Neuropraia) Complete +unctional recovery a+ter st

degree injuries because a'onalcontinuity preserved and changesresponsible +or the conduction loss are+ully reversible

ull restoration o+ +unction may ta,e aslong as % to ( months a+ter the injury


12/56


ClassicationClassication*n" egree (Aonotesis) 'on and myelin sheath disruption ;

leads to conduction bloc, 3ith


13/56


ClassicationClassication*n" egree (Aonotesis) Complete loss o+ motor and sensory

+unctions Complete functional recovery

expected 5ime to recovery depends on severity

and level o+ injury* as a'ons mustregenerate distally =sually months to recovery


14/56


ClassicationClassication+r" egree (Aonotesis) 'ons and endoneurial tube disrupted

Perineurium and epineurium intact Complete loss o+ +unction >nset o+ recovery delayed longer due

to more severe retrograde injury to cell

bodies* 8brosis


15/56


ClassicationClassication,th egree (Aonotesis) >nly epineurium le+t intact

Nerve in continuity* but e'tensiveintraneural scarring and disruption o++ascicular structure


16/56


ClassicationClassication-th egree (Neurotesis) Complete loss o+ continuity o+ nerve

Varying amounts o+ scar +orm bet3eensevered ends* 3ith neuroma +ormationat pro'imal stump


17/56

Causes of Nerve $n%uryCauses of Nerve $n%ury

Compression

)tretch

6schemic 5raumatic


18/56


Acute Compression 6mmediate onset Mechanical

deformation o+ nerve

8bers responsible +orpathologic changes

Chronic Compression $elayed/ gradual

onset Ischemia signi8cant

+actor in genesis o+injury


19/56

Clinical eapleClinical eaple

Doctor, why ismy thigh numb??

MeralgiaParasthetica???


20/56


E'tent and )everity o+Compression6njuries:

Magnitude and rateo+ applied +orce $uration Manner 3hich

applied Alocali2ed or

over a longsegmentB

)tudies have sho3n thatexcessive tourniquettimes and pressures can lead to prolonged

EMG changes

Recoen"e". =E no more than 0-

00mmg above

systolic 4E no more than #'

systolic 4imit duration D#hrs


21/56


Stretch'/ Acute

9 brupt application o+ +orce o+

considerable magnitude9 )tingerF . acute neuropra'ia

*/ Chronic9 )lo3 stretching o+ nerve over

period o+ time

9 =sually tolerate signi8cantly

more

Variable degree o+ injury

Causes: racture displacement* joint dislocation* trauma*etc!


22/56

Physiology of NervePhysiology of Nerve

egenerationegeneration


23/56

Physiology of NervePhysiology of Nerve

RegenerationRegeneration @ate o+ regeneration

varies depending on the

type & location 6n humans* an average

outgro3th o+ -#mm/day is generally

?uoted Pro'imal budding occurs

after month delay


24/56

0unctional Recovery0unctional Recovery

after Nerve $n%uryafter Nerve $n%uryClinical outcomes variable and related to:

! GE 9 single most important +actor

#! 4evel o+ injury - distance regenerating a'onsmust go to reach target organs* distal pro'

%! 4ength o+ injury 2one(! 5ype o+ injury 9 sharp transection crush

! 5iming o+ nerve repair

H! )tatus o+ end organ at time o+ re-innervationI! 5echnical e'pertise o+ surgeon


25/56

Nerve RepairNerve Repair

Priary Repair

Pre+erable: 0-% 3ee,s

6mmediate repair technicallyeasier though emergent repair notnecessary

9 5ime limit o+ repair up to 1 months


26/56

Nerve RepairNerve Repair!pineurial Repair )tandard

>rientation critical

7-0 mono8lament

1roupe" 0ascicular Repair

Not clinically better thanepineurial

6ndications! Median nerve in distal +orearm

#! =lnar nerve in distal +orearm

%! )ciatic nerve in thigh


27/56

Nerve RepairNerve Repair

5ension

Encourages gappingand scar +ormation

@educes blood Jo3:1K elongation .(HK decrease inper+usion

Gra+ting better thanrepair in tensionAautogra+tsB


28/56

Reha2ilitation ofReha2ilitation of

Nerve $n%uriesNerve $n%uries $uring re-innervation

continued motor andsensory rehab critical

)ensory re-educationimproves results

ssists brain inreinterpreting

misdirected a'onimpulses


29/56

!31 4 NC5 Stu"ies!31 4 NC5 Stu"ies


30/56

!31 4 NC5!31 4 NC5

EMG

9 $etermines health o+ muscle and*

indirectly* the nerve supply9 ibrillations )pontaneous activity at restL indicates

denervation

9 6nsertional activity ctivity during needle insertionL high is bad

9 Motor unit potentials e3* 3ide* and lo3 amplitude . "$


31/56

!31 4 NC5!31 4 NC5

NCV

9 Provides additional in+o on nerve +unction

9 Nerve conduction measured AsaltatoryconductionB

9 0 meters/second normal in e'tremities

EMG/NCV


32/56

Nerve CopressionNerve CopressionSyn"roesSyn"roes


33/56

Ra"ial #unnelRa"ial #unnel

Syn"roeSyn"roe)ymptoms Pro'imal / lateral arm pain No motor or sensory

dys+unction !! P6N only No P6N dys+unction Normal EMG/NC) Provocative test: resisted

long 8nger e'tension

5enderness over radialnec, or supinator @ecurrent or unresponsive

lateral epicondylitis9 Coe'ists in K


34/56

Ra"ial #unnelRa"ial #unnel

Syn"roeSyn"roeCauses o+ Compression:

@ecurrent radialvessels Aleash o+enryB

EC@" leading edge

rcade o+ rohse

$istal )upinator

5reatment:

4onger periods o+conservative care H-#mths AN)6$)*splinting* 3or,modi8cationsB

>perative release

o+ten disappointing Care+ul patient

selection


35/56

Posterior $nterosseousPosterior $nterosseous

Nerve Syn"roeNerve Syn"roe Pain at lateral elbo3


36/56

Posterior $nterosseousPosterior $nterosseous

Nerve Syn"roeNerve Syn"roe 5reatment

6nitial conservativeAM@6 r/o massB

$ecompression: i+ norecovery by % monthsor progression

6+ condition persists

1 monthsirreversible muscle8brosis occurs


37/56

Pronator Syn"roePronator Syn"roe

Compression neuropthyo+ pro'imal median n!

)ites o+ Compression:

)upracondylarprocess AK o+populationB

4igament o+ )truthers "icipital aponeurosis $eep head o+ P5 ccessory head o+ P4 >rigin o+ $)


38/56


Con+used 3ith C5) No 5inels sign at 3rist No night symptoms )ensory disturbance

over region o+ palmarcutaneous branch andanterior pro'imal+orearm

Provacative tests:

! le'ion past #0 deg!

- )upracondylar processor ligament o+

)truthers"! @esisted supination 3ith

elbo3 Je'ion - "icipital aponeurosis

C! @esisted pronation 3ith elbo3 e'tended

- Pronator heads$! @esisted M P6P Je'ion

- $)

EMG usually normal* thoughmay be positive in PO &P4


39/56


5reatment: Nonoperative

usually success+ul $ecompression

considered i+ +ails torespond a+ter %-Hmonths

@e?uires globaldecompressionApro'imal to distalBo+ all potential areas


40/56

Anterior $nterosseousAnterior $nterosseous

Nerve Syn"roeNerve Syn"roe)ites o+ Compression: Pronator teres $) rcade 4acertus ibrosus Enlarged bicipital bursa ccessory P4 AGant2ers m!B

$iagnosis Motor loss 3ithout sensory

involvement 4oss o+ P4 & $P - 6nde'

produce characteristic8nding

EMG/NC) diagnostic @/> "rachial Neuritis i+ "/4

9 Parsonage-5urner )yndrome


41/56

Anterior $nterosseousAnterior $nterosseous

Nerve Syn"roeNerve Syn"roe 5reatment:

>bserve +or %-H

months )urgical

decompression+or +ailures


42/56

6ua"rilateral Space6ua"rilateral Space

Syn"roeSyn"roe Compression o+ 'illary

N! and posteriorhumeral circumJe' a

5raumatic and

atraumatic causes Vague shoulder

discom+ort and pain 3ith+atigue 3hen arm heldabove shoulder level

@eproduction o+ s' 3ith

"E@ position Paresthesias and $eltoid

3ea,ness rteriogram A"E@B EMG/NCV may be

positive


43/56

6ua"rilateral Space6ua"rilateral Space

Syn"roeSyn"roe 5reatment:

Conservative +or

H months )urgical

decompression i+:

! ails conservative

#! Positivearteriogram


44/56

Suprascapular NerveSuprascapular Nerve

!ntrapent!ntrapent >verhead repetitive

sports

)uprascapular notch

)pinoglenoid notch

5rauma* traction*space occupyinglesions* etc!

Predominantlymotor nerve


45/56


!ntrapent!ntrapent)ymptoms: Vague dull* achy

pain posterior and

lateral shoulder orasymptomatic


46/56


!ntrapent!ntrapent$iagnosis: EMG/NC) help+ul M@6: space occupying

lesion AganglionB 5reatment: Conservative (-H

months Aunless spaceoccupying lesionpresentB

$ecompression i++ailure o+nonoperativetreatment orprogression


47/56

Stinger Syn"roeStinger Syn"roe

"rachial Ple'us stretch/neuropra'ia

=nilateral shoulderand/or arm pain 3ith

burning dysesthesias ando+ten muscle 3ea,nessinvolving the biceps*deltoid* and spinatusmuscles

)ymptoms transient 3ith+ull recovery typical

More severe neuro injurycan occur

Majority go unreported


48/56


% Mechanisms:

! "rachial ple'usstretch Atraction

injuriesB#! direct blo3 to

the ple'us

%! Nerve root

compression in theneural +oramenAe'tension-compressionB


49/56


5reatment

)ymptomatic usually

May return to play i+PE normal

@emove +rom gamei+ any radiating armpain and neurologic

de8cit or loss o+cervical range o+motion


50/56

#horacic outlet#horacic outlet

syn"roesyn"roe

@elatively common Compression o+ lo3er trun,/medial cord

o+ brachial ple'us and vascular structures )ites o+ compression

9 nt/medial scalene muscles9 Cervical or 8rst rib9 Clavicle malunion or Pec minor9

)ubclavian artery disease Presents 3ith pain and parasthesiasAusually ulnarB 3ith overhead activity9 Complaints usually neurological


51/56


syn"roesyn"roe

)ymptoms9 Presents 3ith pain and parasthesias Ausually

ulnarB 3ith overhead activity

9 Complaints usually neurological Physical E'am

9


52/56


syn"roesyn"roe

$iRcult to diagnose9 NCV/EMG invariably normal

9 $iagnosis dependent on history andvarious non-speci8c provocative tests

@':9 =sually conservativeL P5* stretching*

postural training* mobili2ation* and

strengthening o+ shoulder girdle9 )urgical: only in recalcitrant cases

)urgeon e'perience ,ey


53/56

!7ort #hro2osis!7ort #hro2osis

@are as been described in baseball* s3imming*

3restling* and bac,pac,ing

)': tiredness* heaviness* possible s3elling3ith activities Amay last +or +e3 daysB


54/56

Popliteal ArteryPopliteal Artery

!ntrapent Syn"roe!ntrapent Syn"roe

4ess common diagnosis on diSerential o+ legpain in athletes/runners9 )': pain* +atigue* cramping* paresthesias* s3elling*

coldness

Causes9 Variation in artery course9 ypertrophy or 8brous bands o+ medial gastroc

)ymptoms9 Cal+ cramping +ollo3ing light e'ercise 3hich improves 3ith

vigorous e'ercise9 5ingling sensation in toes a+ter vigorous e'ercise

Physical E'am9 $iminished pulses 3ith ,nee hypere'tension and an,le

plantarJe'ion


55/56

Popliteal ArteryPopliteal Artery

!ntrapent Syn"roe!ntrapent Syn"roe

@anges +rom intermittent claudication topossible li+e threatening limb ischemia

6ntermittent occlusion +rom plantar Je'ion

motion9 May note change in pulse 3ith P rteriogram/M@ @': Adepends on vesselB

9 No vessel injury: release Ausually medial head gastrocB9

Vessel injury: vascular surgical managment


56/56

6uestions 886uestions 88

basic science art & nerve

Documents