Upper Extremity NCS · 2019-10-08 · Upper Extremity NCS Lesion Localization and Characterization...

Upper Extremity NCSLesion Localization and Characterization

2019 Annual AANEM MeetingAustin, Texas

Mark A. Ferrante, MDProfessor, Department of Neurology

Co-Director, Neurophysiology FellowshipAssociate Director, Residency Training ProgramUniversity of Tennessee Health Science Center

Chief of NeurologySection Chief of Neurophysiology,

Director of ALS ClinicVA Medical Center

Memphis, Tennessee

Disclosures• Gator fan• Publishing royalties

– AANEM• What We Measure and What It Means

– Ferrante, 2012

– Cambridge University Press• Comprehensive Electromyography

– Ferrante, 2018

– Demos Publishing• EMG Lesion Localization and

Characterization– Ferrante and Tsao, 2020

Introduction

• Lesion localization and characterization– The major skills of the EDX provider– Lesion localization – Lesion characterization

• Fiber type involved: sensory or motor• Pathology: Axon loss or demyelination• Severity• Temporal characteristics (needle EMG)

– Acute, subacute, or chronic– Rate of progression

– Introductory material cases

• Mechanisms of nerve injury– Large number

• Pathology and pathophysiology– Limited

• Myelin disruption (demyelination)– Conduction slowing (DMCS)– Conduction block (DMCB)

• Axon disruption (Wallerian degeneration)– Conduction failure– Prior to Wallerian degeneration

» Transient “conduction block” pattern

Nerve Fiber Disruption• Focal demyelination

– Focal effects• Focal axon disruption

– Initially: Focal effects– Later: Distal effects

– Wallerian degeneration

Ferrante MA, Tsao B. EMG Lesion Localization and Characterization, 2020

The pathophysiologies

associated with demyelination

DMCS, uniform

DMCS, non-uniform

DMCB

Forearm

Elbow

Below SG

Above SG

Motor NCS are able to assess long segments of nerve

– Timing of Wallerian degeneration• Motor axon terminals and endplates degenerate first

– NMJ transmission failure occurs before nerve fiber conduction failure

– CMAP abnormalities precede SNAP abnormalities» CMAPs: day 3 to day 7» SNAPs: day 6 to day 10

Ferrante MA. Comprehensive Electromyography9

• NCS identify– Focal DM and early axon disruption

• Between the stimulating and recording sites

– Screens for Wallerian degeneration proximal to these sites

• All the way to the cell bodes of origin

Ferrante. Muscle and Nerve 2004;30:547-568.

ANTERIOR PRIIMARY RAMI C5 C6 C7 C8 T1Proximal Nerve Innervation

Rhomboids (dorsal scapular)Spinati (suprascapular)Deltoid (axillary)Biceps (musculocutaneous)Brachialis (musculocutaneous)

Radial Nerve InnervationBrachioradialisTricepsAnconeusExtensor carpi radialisExtensor pollicis brevisExtensor indicis

Median Nerve InnervationPronator teresFlexor carpi radialisFlexor pollicis longusPronator quadratusAbductor pollicis brevis

Ulnar Nerve InnervationFlexor carpi ulnarisFlexor digitorum profundus (D4,D5)Abductor digiti minimiAdductor polllicisFirst dorsal interosseous

POSTERIOR PRIMARY RAMICervical paraspinal musclesHigh thoracic paraspinal muscles

predominant contributionsometimes significant contributionminor contribution

For the motor NCS

Myotomal charts indicate:

• the root innervation• the nerve innervation

Example: Biceps


LABC SNAP

Ferrante and Wilbourn, Muscle and Nerve, 1995

Med-D1 SNAP


Superficial Radial SNAP


Med-D2 SNAP


Med-D3 SNAP


Uln-D5 SNAP


MABC SNAP


C6C6>7

C6

C7>6C7

C8T1


C6

C7

C8

T1

C5

Routine Screening NCS of Upper Extremity(Only weakly assesses upper plexus)

Ulnar-ADM

Median-APB

Radial

Med-D2

Uln-D5

C6

C7

C8

T1

C5

NCS Assessment of Upper Plexus

Musculocutaneous-BC

Axillary-Deltoid

LABC (100%)

Med-D1 (100%)

Radial (60%)*

NCS Assessment of Middle Plexus

C6

C7

C8

T1

C5

Med-D2 (80%)*

Med-D3 (70%)

Radial (40%)*

C6

C7

C8

T1

C5

NCS Assessment of Lower Plexus

Uln-D5 (100%)*

MABC (100%)

Radial – distal forearm

Ulnar – ADM or FDI*

Median – APB*

C6

C7

C8

T1

C5

NCS Assessment of Lateral CordLABC (100%)

Med-D1 (100%)

Med-D2 (100%)*

Med-D3 (80%)

Musculocutaneous - BC

C6

C7

C8

T1

C5

NCS Assessment of Posterior Cord

Axillary – Deltoid

Radial – Proximal FA

Radial – Distal FA

Radial (100%)*

C6

C7

C8

T1

C5

NCS Assessment of Medial Cord

Uln-D5 (100%)*

MABC (100%)

Ulnar – ADM/FDI*

Median – APB*

• Which sensory NCS should be done first?– Perform “routine” sensory NCS

+ NCS to address the referral diagnosis+ NCS to address the clinical features

– Based on identified abnormalities, add others• For C6,7 abnormalities (Med-D2; SRN)

– Add LABC and Med-D1• For C8 abnormalities (Uln-D5)

– Add MABC• Add contralateral studies when indicated

EDX CASE STUDIESLocalization

Pathophysiology

Severity

Temporal

Case 1A

• 67yo RH male– Episodic hand numbness and tingling x 5 years, R > L– Present upon awakening– Precipitated by driving– Occur spontaneously while seated at rest

• No neck pain• Examination normal

– Hand sensation – Thenar eminence strength and bulk

• Clinical features– Suggest bilateral CTS, right > left– Dominant limb first and worst

• Exceptions– Profession and hobbies

» Ferrante, Federal Practitioner, 2016;33:10-15

• Start NCS– Screening sensory NCS

• Start with RUE– More symptomatic side– If Median-D2 is normal, add

palmar NCS» More sensitive to CTS

Median-D2Ulnar-D5

Superficial radial

Perform Contralateral NCSMedian-D2

CASE 1A UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEETLEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUCSENSORY DRG

Median-D2 C6,7 4.2 6.4Ulnar-D5 C8 2.9 6.2

Superficial radial C6,7 2.4 13.5



Median-D2 C6,7 3.6 12.0 4.2 6.4Ulnar-D5 C8 2.9 6.2

Superficial radial C6,7 2.4 13.5Median Palmar 2.4 18.2Ulnar Palmar 1.9 12.5

Localization Bilateral Median: distal to the wrist stimulation sites

Pathophysiology Demyelinating and axon loss on the right; demyelinating on the left

Severity Mild to mild-moderate on the right and mild on the left

Temporal Chronic by history (this is determined by the needle EMG findings)

Which Motor NCS?Routine motor NCS x RUE

Median-APB x LUE

CASE 1AUPPER EXTREMITY NERVE CONDUCTION STUDY

WORKSHEETLEFT RIGHT

NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC

SENSORY DRGMedian-D2 C6,7 3.6 12.0 4.2 6.4Ulnar-D5 C8 2.9 6.2

Spfcl radial C6,7 2.4 13.5Median Palmar 2.4 18.2Ulnar Palmar 1.9 12.5

MOTORStim Site

Median-APB Wrist 3.4 7.6 4.1 5.8Elbow 5.5 51

Ulnar-ADM Wrist 2.4 11.4 28.8BE 9.6 52 26.8AE 8.8 53 26.7

Localization Distal to the wrist stimulation site on both sidesPathophysiology DMCS and axon loss on the right, involving the sensory and motor nerve fibers

DMCS on the left, involving the sensory nerve fibersSeverity At least moderate on the right and mild on the leftTemporal Chronic by history

UPPER EXTREMITY NEEDLE EMG WORKSHEET

CASE 1A

Insertional activity Spontaneous Activity MUAP Analysis

Normal IPSWs SCP Other None Fibs Fascs OtherMUAP

RecruitmentMUAP

MorphologyRIGHT

APB X X Normal NormalFDI X X Normal Normal

Pron teres X X Normal Normal

LEFTAPB X X Normal Normal

Case 1A Impression

1. Bilateral Median Neuropathies (e.g., carpal tunnel syndrome)• The above are demyelinating and axon loss in nature on the right

and demyelinating in nature on the left, involve the sensory and motor nerve fibers on the right and the sensory nerve fibers on the left, and are located at or distal to the wrist on both sides.

• Electrically, the abnormalities are moderate in severity on the right and mild in severity on the left.

Case 1B• 56yo RH male

– Episodic hand numbness and tingling x 2 years, R > L– Present upon awakening– Precipitated by driving– Occur spontaneously while seated at rest


– Hand sensation decreased• Median distribution

– Thenar eminence muscles• Normal strength• Thenar eminence

– Wasting, mild in degree

• Due to time constraints, we will only discuss the ipsilateral findings• Hx s/o CTS

CASE 1B UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEETLEFT RIGHT


Median-D2 C6,7 NRUlnar-D5 C8 2.7 12.2

Superficial radial C6,7 2.4 17.8Median Palmar NR

Localization Median nerve, lateral cord, upper plexus, C6/7 DRGPathophysiology Axon loss, sensory nerve fibersSeverity Unclear (at least moderate)Temporal Chronic by history




Superficial radial C6,7 2.4 17.8Median Palmar NR

MOTORStim Site

Median-APB Wrist 4.6 4.8Elbow 4.5 51

Ulnar-ADM Wrist 2.3 10.9BE 10.3 57AE 10.3 58

Localization Median nerve, distal to the stimulation sitePathophysiology Demyelination and axon loss; involves the sensory and motor nerve fibersSeverity Unclear (at least moderate)Temporal Chronic by history

Case 1C• 43yo RH male

– Episodic hand numbness and tingling x 10 years, R > L– Present upon awakening– Precipitated by driving– Occur spontaneously while seated at rest


– Hand sensation decreased• Median distribution

– Thenar eminence muscles• Normal strength• Severe thenar eminence wasting

• Due to time constraints, we will only discuss the ipsilateral findings• Hx s/o CTS, so continue with motor NCS

CASE 1C UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEETLEFT RIGHT



Superficial radial C6,7 2.4 24.9Median Palmar NRUlnar Palmar

Localization Median nerve, lateral cord, upper plexus, C6/7 DRGPathophysiology Axon loss, sensory nerve fibersSeverity Unclear (at least moderate)Temporal Chronic by history

CASE 1CUPPER EXTREMITY NERVE CONDUCTION STUDY

WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 NRUlnar-D5 C8 2.8 17.5

Spfcl radial C6,7 2.4 24.9

Median PalmarUlnar Palmar

MOTORStim Site

Median-APB Wrist NRElbow


Localization Median nerve at or distal to axillaPathophysiology Axon loss, sensory and motor nerve fibersSeverity SevereTemporal Chronic by history

CASE 1CUPPER EXTREMITY NERVE CONDUCTION STUDY

WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 NRUlnar-D5 C8 2.8 17.5

Spfcl radial C6,7 2.4 24.9

MOTORStim Site

Median-APB Wrist NRElbow


Median-L2 Wrist 5.4 1.1

Localization Median nerve at or distal to stimulation sitePathophysiology Axon loss, sensory and motor nerve fibersSeverity SevereTemporal Chronic by history

Case 2• 70yo RH male referred for RH numbness and

weakness– Symptom onset

• 6 weeks ago, immediately following a 2-vessel stenting procedure

– Axillary approach • Examination

– Diminished sensation -- the lateral 3.5 digits (“splits 4”) and thenar eminence

– Severe weakness• Median nerve-innervated hand intrinsic muscles• Anterior interosseous nerve-innervated muscles• Pronator teres and flexor carpi radialis muscles -- normal

strength• Clinical thoughts

– Iatrogenic median neuropathy

CASE 2 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEETLEFT RIGHT


Median-D1 C6 NRMedian-D2 C6,7 NRMedian-D3 C6,7,8 NRUlnar-D5 C8 2.9 15.2


Localization Median nerve or lateral cordPathophysiology Axon lossSeverity At least moderate-severeTemporal 6 weeks by history

Add LABC sensory NCS to differentiate median nerve

from lateral cord




Superficial radial C6,7 2.6 17.4LABC C6 2.6 11.2

Localization Median nerve or distal lateral cordPathophysiology Axon lossSeverity At least moderate to moderate-severeTemporal Subacute by history

Motor NCS

Ipsilateral: Routine + Median-L2Contralateral add Median-APB and Median-L2




Superficial radial C6,7 2.6 17.4LABC C6 2.6 11.2

MOTORStim Site

Median-APB Wrist 3.4 12.6 42.7 4.0 3.2 12.5Elbow 2.8 38 11.2


Median-L2 Wrist 3.9 2.2 4.6 0.5

Localization Median nervePathophysiology Axon lossSeverity SevereTemporal Subacute by history


CASE 2Insertional activity Spontaneous Activity MUAP Analysis


RecruitmentMUAP

Morphology

RIGHTAPB X 3+ Neurogenic, sev NormalFDI X X Normal NormalEI X X Normal Normal

FPL X 3+ Neurogenic, mild NormalPronator teres X X 1+ Normal Normal

BC, LH X X Normal NormalTC, LH X X Normal Normal

FCR X 2+ Normal NormalLumbrical 2 X 3+ Neurogenic, sev Normal

Low cerv psp X X -- --High thor psp X X -- --

Localization Median nervePathophysiology Axon lossSeverity Very severe (based on severity of neurogenic recruitment)Temporal Acute-subacute (high amplitude fibrillation potentials)

Case 2 Impression

1. Right Median Neuropathy• The above is axon loss in nature, involves the sensory and motor nerve

fibers, and is severe in degree.• The lesion involves about 75% of the motor axons to the APB muscle

and 75% of the motor axons to the second lumbrical muscle.• The lesion is located proximal to the departure site of the motor branch

to the pronator teres muscle. Because the median nerve does not give off motor branches in the arm, more precise localization is not possible.

• The lesion is acute to subacute given the high amplitude fibrillation potentials and the lack of chronic changes. This is consistent with the onset reported by the patient.

Case 3

• 70yo RHD male– Awoke with left hand tingling and inability to extend his wrist and

fingers 25 days ago– Examination

• Decreased sensation superficial radial nerve distribution• Weakness of wrist extension without radial deviation• Forearm extension strength is normal



Median-D2 C6,7 3.3 18.1Ulnar-D5 C8 2.7 10.8

Superficial radial C6,7 2.5 21.6 2.6 28.7

• The sensory NCS are normal• The superficial radial response asymmetry is of unclear

significance• It may reflect axon loss, but if so it is minimal-mild in degree

• Can proceed to motor BCS• Routine left motor NCS• Add the distal and proximal radial motor responses

bilaterally



SENSORY DRGMedian-D2 C6,7 3.3 18.1Ulnar-D5 C8 2.7 10.8

Spfcl Radial C6,7 2.5 21.6 2.6 28.7

MOTOR Stim SiteMedian-APB Wrist 3.6 8.7

Elbow 8.6 54.2Ulnar-ADM Wrist 2.8 7.2

Elbow 7.1 55.3Radial-EI Mid-FA 2.1 4.0 28.9 2.2 6.4 32.9

Elbow 3.8 28.2Below SG 3.8 27.7Above SG 0.8 3.8

Radial-ED Elbow 2.7 6.2 40.0 2.6 7.1 45.6Below SG 5.7 38.5Above SG 1.1 8.4

Localization Spiral groovePathophysiology DMCB; possible minor axon loss (< 10%)Severity Severe for the DMCBTemporal 25 days based on history


CASE 3

Insertional activity Spontaneous Activity MUAP Analysis

Normal

IPSWs

SCP Other None Fibs

Fascs

OtherMUAP

RecruitmentMUAP

Morphology

LEFTFDI X X Normal NormalEI X 3+ Severe neurogenic Normal

FPL X X Normal NormalPron teres X X Normal NormalBC, LH X X Normal NormalTC, LH X X Normal Normal

Deltoid, MH X X Normal NormalBrachiorad 3+ Severe neurogenic NormalECR-longus X 3+ Severe neurogenic Normal

ED X 2+ Severe neurogenic NormalAnconeus X X Normal Normal

Low C psp X X -- --High T psp X X -- --

RIGHTEI X X Normal Normal

Brachiorad X X Normal Normal

Localization Spiral groovePathophysiology DMCB >> axon lossSeverity Severe for the DMCB; mild for the axon lossTemporal c/w the 25 days reported

Radial-EI Mid-FA 2.1 4.0 28.9 2.2 6.4 32.9Elbow 3.8 28.2

Below SG 3.8 27.7Above SG 0.8 3.8

Radial-ED Elbow 2.7 6.2 40.0 2.6 7.1 45.6Below SG 5.7 38.5Above SG 1.1 8.4

Calculating Severity

For the motor axons to the EDC muscleAXON LOSS: 1 - 40.0/45.6 = 1 - 0.88 = 0.12 = 12%

DMCB: 1 - 8.4/38.5 = 1 - 0.22 = 0.78 = 0.78 X 0.88 = 69%NORMAL: 100% - 81%= 19%

For the motor axons to the EI muscleAXON LOSS: 1 – 28.9/32.9 = 1 - 0.88 = 0.12 = 12%

DMCB: 1 – 3.8/27.7 = 1 – 0.14 = 0.86 = 0.86 X 0.88 = 76%NORMAL: 100% - 88% = 12%

Case 3 Impression

1. Left Radial Neuropathy• The above is demyelinating conduction block >> axon loss in

nature, involves the motor nerve fibers (and the sensory nerve fibers by clinical examination), is located within the spiral groove, and is severe in degree for the demyelinating conduction block component and mild for the axon loss component.

• The findings are consistent with the 25-day onset reported by the patient.

Case 4

• 52yo RHD female x left UE numbness and weakness– Pacemaker placement 2 months ago– Symptoms started immediately after procedure

• Weakness– Forearm flexion (C5,6-MC) and pronation (C6,7-median)

• Numbness along the lateral aspect of the forearm (LABC) and hand (median and radial)

– Sparing the skin overlying the FDI muscle


NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUCSENSORY DRGMedian-D2 C6,7 3.1 8.6Ulnar-D5 C8 2.8 12.3


INTERPRETATION

• The Med-D2 response is reduced in amplitude• POTENTIAL LOCALIZATION

• Median nerve, lateral cord, upper/middle plexus, C6,7 DRG

ARE FURTHER SENSORY NCS INDICATED?

• C6,7 DRG add LABC and Med-D1 sensory NCS• On the contralateral side

• Med-D2 for comparison purposes• LABC and Med-D1

IS THIS CTS?

CASE 4UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET

LEFT RIGHTNCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC

SENSORY DRG

Median-D2 C6,7 3.1 8.6 3.0 28.3

Ulnar-D5 C8 2.8 12.3


LABC C6 2.7 5.1 2.5 16.5

Median-D1 C6 3.2 7.2 3.1 21.9

Localization Lateral cord > upper plexus, C6 DRGPathophysiology Axon lossSeverity At least moderate (severity is best addressed by the motor NCS)Temporal 2 months by history

Which motor NCS should be performed?• Ipsilateral: Routine NCS; Musculocutaneous-BC; Axillary-Deltoid• Contralateral: Musculocutaneous-BC; Axillary-Deltoid

CASE 4 UPPER EXTREMITY NERVE CONDUCTION STUDY WORKSHEET

LEFT RIGHTNCS

PERFORMED LAT AMP CV nAUC LAT AMP CV nAUC

SENSORY DRGMedian-D2 C6,7 3.1 8.6 3.0 28.3Ulnar-D5 C8 2.8 12.3

Superficial radial C6,7 2.4 20.0 2.5 24.1LABC C6 2.7 5.1 2.5 16.5

Median-D1 C6 3.2 7.2 3.1 21.9

MOTORStim Site

Median-APB Wrist 3.5 7.2Elbow 7.1 56

Ulnar-ADM Wrist 2.8 8.3Elbow 8.1 54

Musculo-BC Axilla 3.8 2.7 3.6 5.6SCF 2.6 56

Axillary-Deltoid SCF 4.1 9.2 3.9 8.6

Localization Lateral cordPathophysiology Axon lossSeverity Moderate-severe (1 - 2.7/5.6) x 100% = 52% motor axons to bicepsTemporal 2 months by history




RecruitmentMUAP

MorphologyLEFT

FDI X X Normal NormalEI X X Normal Normal

FPL X X Normal NormalPron teres X 3+ Normal NormalBC, LH X 3+ Mild neurogenic Normal

FCR X 2+ Normal NormalTC, LH X X Normal Normal

Deltoid, MH X X Normal NormalBrachioradialis X X Normal NormalInfraspinatus X X Normal Normal


RIGHTPron teres X X Normal NormalBC, LH X X Normal Normal

Brachioradialis X X Normal NormalDeltoid, MH X X Normal Normal

Localization Lateral cordPathophysiology Axon lossSeverity Moderate-severe (1 - 2.7/5.6) x 100% = 52% motor axons to bicepsTemporal Lack of collateral sprouting supports the 2-month history reported

1. Lateral Cord Brachial Plexus Lesion

The above is axon loss in nature, involves the sensory and motor nerve fibers, and

is moderate-severe in degree. The temporal features of the abnormalities are

consistent with an onset two months ago as reported by the patient(i.e., there is no

EDX evidence of reinnervation through collateral sprouting).

Case 4 Impression

Case 5

• 41yo LHD female– Fell onto outstretched left UE 1 month ago– Subjective

• Numbness along the medial hand and forearm• Weakness of grip

– Examination• Medial hand and medial forearm numbness• Hand weakness, including FDP-D4• Extensor indicis weakness

– Start with routine sensory NCS

CASE 5UPPER EXTREMITY NERVE CONDUCTION STUDY

WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 3.1 30.3Ulnar-D5 C8 NRS-Radial C6,7 2.3 21.5

Localization Ulnar nerve, medial cord, lower plexus, C8 DRGPathophysiology Axon lossSeverity At least mild-moderate (motor NCS are best for severity assessment)Temporal 1 month by history

When the Ulnar-D5 is abnormal, add the MABCIf the MABC is normal, add the DUC

Add the contralateral MABC


WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 3.1 30.3Ulnar-D5 C8 NRS-Radial C6,7 2.3 21.5MABC T1 NR 2.4 12.4

Localization Medial cord, lower plexus, C8/T1 DRGPathophysiology Axon lossSeverity At least moderate (motor NCS are best for severity assessment)Temporal 1 month by history

What motor NCS?

Ipsilateral: routine NCS, Ulnar-FDI, Radial-EIContralateral: Ulnar-ADM, Ulnar-FDI, Radial-EI

C6

C7

C8

T1

C5

Case 5 – Sensory Responses

Upper trunk

Middle trunk

Lower trunk

Lateral cord

Posteriorcord

Medial cord

CCF© 2002



SENSORY DRGMedian-D2 C6,7 3.1 30.3Ulnar-D5 C8 NR 2.8 14.4S-Radial C6,7 2.3 21.5MABC T1 NR 2.4 12.4

MOTORStim Site

Median-APB Wrist 3.6 4.6 3.5 13.7Elbow 4.4 54 13.7

Ulnar-ADM Wrist 2.9 4.2 2.9 12.5AE 4.1 52 12.4

Ulnar-FDI Wrist 3.9 5.1 3.7 9.2AE 5.1 55 9.2

Radial-EI Forearm 1.7 1.3 1.8 4.3Elbow 1.3 51 4.3

Localization Lower plexusPathophysiology Axon lossSeverity SevereTemporal 1 month by history (best determined by needle EMG)




RecruitmentMUAP

MorphologyLEFTAPB X 2+ Mod neurogenic NormalFDI X 3+ Mod neurogenic NormalEI X 3+ Sev neurogenic Normal

FPL X 3+ Mod neurogenic NormalPron teres X X Normal NormalBC, LH X X Normal NormalTC, LH X 1+ Normal Normal


RIGHTAPB X X Normal NormalFDI X X Normal NormalEI X X Normal Normal

Localization Lower plexusPathophysiology Axon lossSeverity SevereTemporal c/w the 1 month history reported by the patient (no collateral sprouting)

Case 6• 26yo RHD female x LUE pain and numbness• Aching pain x 10 years

– Medial aspect of the left arm and forearm• Numbness x several years

– Intermittent, medial aspect of the left forearm and hand– Precipitated by supine

• Left thenar eminence atrophy– Noticed by her friend

• Weakness– D1 abduction, D1 flexion, D2 extension, finger abduction

• Sensation– Diminished along the medial aspect of the forearm and hand

• Routine sensory NCS


WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 3.1 51Ulnar-D5 C8 2.7 16S-Radial C6,7 2.2 59

The screening sensory NCS are normalThe Ulnar-D5 response is suspicious

Collect a contralateral Ulnar-D5 response


WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 3.1 51Ulnar-D5 C8 2.7 16 2.6 41.7S-Radial C6,7 2.2 59

Add MABC (possibly bilaterally)If normal, add DUC


WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 3.1 51.5Ulnar-D5 C8 2.7 16.1 2.6 41.7S-Radial C6,7 2.2 59.3MABC T1 NR 2.5 15.8

Localization Medial cord or lower plexusPathophysiology Axon lossSeverity Absent for MABC; relatively abnormal for Ulnar-D5 (T1 > C8)Temporal Chronic by history (best determined by needle EMG)

What motor NCS?Ipsilateral: routine, Ulnar-FDI; Radial-EI

(for localization)

Contralateral: Ulnar-ADM, Ulnar-FDI, and Radial-EI NCS(for severity assessment)



SENSORY DRGMedian-D2 C6,7 3.1 51.5Ulnar-D5 C8 2.7 16.1 2.6 41.7S-Radial C6,7 2.2 59.3MABC T1 NR 2.5 15.8

MOTOR Stim SiteMedian-APB Wrist 3.6 2.2 3.5 12.4

Elbow 2.1 51 12.4 52Ulnar-ADM Wrist 2.7 8.3 2.7 14.1

AE 8.1 53 14.0 56Ulnar-FDI Wrist 4.2 7.9 4.1 15.3

AE 7.9 54 15.1 54Radial-EI Forearm 1.6 2.1 1.7 4.6

Elbow 2.1 52 4.6 53

Localization Lower plexusPathophysiology Axon lossSeverity Severe (T1 > C8)Temporal Chronic by history (best determined by needle EMG)




RecruitmentMUAP

MorphologyLEFTAPB X 3+ Severe neurogenic Severe CMALFDI X 1+ Mild neurogenic Moderate CMALEI X 1+ Mod neurogenic Moderate CMAL

FPL X 2+ Mod neurogenic Moderate CMALPron teres X X Normal NormalBC, LH X X Normal NormalTC, LH X X Normal Mild CMAL


RIGHTAPB X X Normal NormalFDI X X Normal NormalEI X X Normal Normal

TC, LH X X Normal Normal

Localization Lower plexusPathophysiology Axon lossSeverity Severe (T1 > C8)Temporal Chronic (as reported by the patient) and progressive


Case 7

• 71yo RHD male x suspected post-operative left ulnar neuropathy– Open heart surgery 26 days ago – Left grip weakness– Numbness along the medial aspect of the left hand

– Examination (not provided)• Check cutaneous distributions of ulnar and MABC nerves• Check strength of ulnar, FPL, and EI muscles


WORKSHEETLEFT RIGHT

NCS PERFORMED LAT AMP CV

nAUC LAT AMP CV nAUC

SENSORY DRGMedian-D2 C6,7 3.0 14.7Ulnar-D5 C8 NR


Add MABC (possibly bilaterally)If normal, add DUC (likely bilaterally


WORKSHEETLEFT RIGHT


SENSORY DRGMedian-D2 C6,7 3.0 14.7Ulnar-D5 C8 NR

Superficial radial C6,7 2.5 18.3MABC T1 2.7 11.6 2.7 10.3DUC C8 NR 2.9 7.3

Localization Ulnar nerve, medial cord, lower plexusPathophysiology Axon lossSeverity Moderate-severe (best determined by motor NCS)Temporal 26 days, per history provided by patient and referring physician

What motor NCS?Ipsilateral: Routine, Ulnar-FDI; Radial-EI

(for localization)

Contralateral: Ulnar-ADM, Ulnar-FDI, and +/- Radial NCS(for severity assessment)


NCS PERFORMED LAT AMP CV nAUC LAT AMP CV nAUCSENSORY DRGMedian-D2 C6,7 3.0 14.7Ulnar-D5 C8 NR 8.1 8.1

Superficial radial C6,7 2.5 18.3MABC T1 2.7 11.6DUC C8 NR 2.9 7.3

MOTOR Stim SiteMedian-APB Wrist 3.7 7.3 3.6 9.1

Elbow 7.3 54 8.9 53Ulnar-ADM Wrist 3.0 4.6 2.9 10.4

Elbow 4.5 55 10.1 58Ulnar-FDI Wrist 3.9 4.1 3.9 8.6

Elbow 4.1 51 8.6 54Radial-EI Forearm 2.3 1.1 2.2 3.4

Localization Lower plexusPathophysiology Axon lossSeverity SevereTemporal 26 days, as reported by the patient and the referring physician




RecruitmentMUAP

MorphologyLEFTAPB X 2+ Mild neurogenic NormalFDI 2+ 3+ Mild neurogenic NormalEI 1+ 3+ Mod neurogenic Normal

FPL X 2+ Mod neurogenic NormalPron teres X X Normal NormalBC, LH X X Normal NormalTC, LH X 2+ Normal Normal


RIGHTAPB X X Normal NormalFDI X X Normal NormalEI X X Normal NormalTC X X Normal Normal

Localization Lower plexusPathophysiology Axon lossSeverity SevereTemporal c/w the 26 days reported by the patient and referring provider (no CMAL)

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Upper Extremity NCS · 2019-10-08 · Upper Extremity NCS Lesion Localization and Characterization...

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