Practical tips for trainees II.
NCS and near nerve
Edina Timea Varga MD, PhD
Department of Neurology, University of Szeged
30 August 2017
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I. Nerve conduction study (NCS) – general
aspects
II. Motor nerve conduction studies
I. inchig
II. (F-waves, H-reflex)
III. Sensory nerve conduction studies
IV. Near nerve measurements
motor NCS
sensory NCS
http://bcs.whfreeman.com/thelifewire9e
Purves et al. Life The Science of Biology IVth Edition 1995.
http://chadwaterbury.com
http://emedicine.medscape.com/article/1846028-overview
http://jdr.sagepub.com
http://www.erikstalberg.com/www.varganeuro.com
axonmembrane
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I. General aspects
NCS environment
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NCS environment
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Accessories
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Accessories
1. Skin prep pads / disinfectant
2. Ground electrode
3. Stimulator
4. Registering electrodes (superficial / needle)
5. Electrode cables
6. Ring electrodes
7. (Electrode gel)
8. Thermometer (built in / external)
9. Distilled water (prevents fur formation)
10. Marker
11. Gloves
12. Tape-measure
13. Medical tape /cotton wool
14. Heating lamp / warm water bath / heating pads
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Patient information
Contraindications
Inconvenience
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II-III. Motor and sensory NCS
Nerve conduction study (NCS)
=electroneurography (ENG)
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orthodromic - antidromic
Nerve conduction study (NCS)
=electroneurography (ENG)
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orthodromic - antidromic
Nerve conduction study (NCS)
=electroneurography (ENG)
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orthodromic - antidromic
temperature
position of ground electrode
supramaximal stimulation
repeatable curves
averaging (sensory NCS)
Nerve conduction study (NCS)
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Nerve conduction study (NCS)
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Nerve conduction study (NCS)
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Nerve conduction studies (NCS)
motor NCS
sensory NCS
http://bcs.whfreeman.com/thelifewire9e
Purves et al. Life The Science of Biology IVth Edition 1995.
http://chadwaterbury.com
http://emedicine.medscape.com/article/1846028-overview
http://jdr.sagepub.com
http://www.erikstalberg.com/www.varganeuro.com
Nerve conduction studies (NCS)
motor NCS
sensory NCS
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onset/distalis latency (DL)
Nerve conduction studies (NCS)
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onset/distalis latency (DL)
Nerve conduction studies (NCS)
∆T
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amplitude
amplitude
Nerve conduction studies (NCS)
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∆T
conduction velocity=distance / ΔT
Nerve conduction studies (NCS)
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Nerve conduction studies (NCS)
duration
area under the curve
morphology
temporal dispersion
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conduction block
https://mmcneuro.files.wordpress.com/2012/12/mmn-cb.jpg?w=271&h=322
needle electrode
superficial registration
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Nerve conduction studies (NCS)
 stimulation with superficial electrode
 registration with needle
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Nerve conduction studies (NCS)
Radial nerve motor NCS
∆T
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Motor NCS of median nerve
1.
2.
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Motor NCS of ulnar nerve
Motor NCS of ulnar nerve
Registration simultaneously from two muscles (AMD – FDI)
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Motor NCS of ulnar nerve
INCHING
1 inch= 2.54 cm
Inching
possible about any
nerve segments
localisation
1 inch= 2.54 cm
Sensory NCSs of median nerve
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Sensory NCSs of median nerve
Orthodromic stimulation over 2 different segments
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Sensory NCS of radial nerve
antidromic stimulation
 superficial electrodes
 sensory nerve conduction
Sensory NCS of medial and
lateral plantar nerve
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Carpal tunnel syndrome (CTS)
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Carpal tunnel syndrome (CTS)
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MODERATE
Carpal tunnel syndrome
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MILD
MODERATE
SEVERE
Muscle Nerve. 2011 Oct;44(4):597-607
Compression neuropathies
Affected nerve Site of compression
suprascapular nerve lig. transversum scapulae superius
brachial plexus / medial fasciculus TOS – thoracic outlet syndrome
median nerve
wrist
elbow
CTS
pronator teres sy
interosseus anterior sy
ulnar nerve
wrist
elbow
UTS
cubitalis tunnel sy/Guyon’s tunnel
dorsal interosseal nerve radialis tunnel sy
(where the nerve enters supinator
muscle)
lateral femoral cutaneous nerve
(meralgia paraesthetica)
ligamentum inguinale
obturator nerve obturator channel
piriformis nerve hiatus piriformis
posterior tibial nerve tarsal tunnel syndrome
(malleolus medialis-flexor retinaculum)
peroneal nerve / plantar branches Morton’s metatarsalgia www.varganeuro.com
Indication of NCS
………….
……………………….
………………………………………
…………………………………………………..
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?
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Near nerve technique
closer to the nerve
higher detectable answer
more precise information
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Indication
If the nerve could not be investigated by non/invasive
technique (superficial NCS, US, MRI…)
If the nerve is
 diameter<7 um (n. calcaneus med.)
 running deeply (ulnar, alveolaris inf. nerve)
 hard to differentiate the distal branches(plantar/palmar
interdigital branches): tarsal tunnel/Morton’s metatarsalgia
n. cut. fem. lat.
Became more and more limited due to high
resolution ultrasound…
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Contraindications
 local infection, decubitus
 anticoagulant treatment (?) – rel.
 external pacemaker – abs.
 implanted PM, ICD, (VNS, DBS) – rel.
Al-Sheekle, Preston, Shapiro Muscle&Nerve 2003; 27:517-26. www.varganeuro.com
Possible complications
 bleeding
 infection (SINGLE USE!!! Needles are acceptable
HIV, CJD, hepatitis – HBV!), needle top!
 nerve lesion
 pain
 electric damage
Al-Sheekle, Preston, Shapiro Muscle&Nerve 2003; 27:517-26. www.varganeuro.com
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 n. cutaneus femoris lateralis
 n. tibialis / rami plantares mediales et laterales
 n. ulnaris
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N. cutaneus femoris lateralis
http://www.neurofys.uu.se/v2/docs/metod/index_eng.php
Preston&Shapiro 2. Edition www.varganeuro.com
 superficial electrodes
 sensory nerve conduction
Sensory NCS of medial and
lateral plantar nerve
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Near nerve technique
tarsal tunnel syndrome Morton’s metatarsalgia
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http://www.neurofys.uu.se/v2/docs/metod/index_eng.php
http://www.aafp.org/afp/2003/1001/p1356.html
Morton’s metatarsalgia
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Morton’s metatarsalgia
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Ulnar nerve neuropathy
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Cubital tunnel syndrome – near nerve
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NORMAL VALUES
age
gender
height
own lab
intraindividual
(side comparison)
Reporting
Description
Conclusion
Clinical comment
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Special thanks to
Professor S. Beniczky
Professor A. Antal
Professor E. Stålberg
Rudsel Schoobaar, Cadwell Industries, Inc.
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Thank you for your attention
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Practical tips for trainees: Nerve conduction studies, near nerve technique