The Carpal Tunnel - Uppsala University. CTS SW.pdf · The Carpal Tunnel CTS Dysfunction of median...
Transcript of The Carpal Tunnel - Uppsala University. CTS SW.pdf · The Carpal Tunnel CTS Dysfunction of median...
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The Carpal Tunnel
CTSDysfunction of median nerve in the carpal tunnel resulting in
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Symptoms in CTS
– pain and numbness in the abd– worse on finger activity– aggravated by forceful grippinggg y g pp g– symptoms more prominent at night-morning
(flexed fingers)
Signs of CTS
2-point discrimination > 3.4 mmPhalen sign digit 3Tinel signTinel signweakness of thenar muscles wrist ratio (lat vs dors-volar) > 0.7
EDX in CTS; principles
• Motor:– Absolute values– Comparison with ulnarComparison with ulnar
• Sensory:– Absolute values– Comparison with other nerves
• med-uln• med-rad
– Transcarpal tunnel compared to distal segment
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EDX in CTS: pathophysiology
Test motor and sensory Median nerve for :Demyelination (slowing)Axonal degeneration (low ampl+ denerv)Axonal degeneration (low ampl+ denerv)Conduction block (prox-dist stim)
Motor: APB,ADM
80 mm
80 mm
Stimulation in the palm
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Motor: APB transcarpal
CTS, motor(normal amplitude/increased distal lat. at wrist)
Stimulation site:
palm
wrist
above elbow
Demyelination, no axonal loss
CTS, motor (low amplitude/increased distal lat. at wrist )
Stimulation site:
palm
wrist
above elbow
Demyelination + conduction block
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CTS, motor (low amplitude/increased distal lat. at wrist )
Stimulation site:
lpalm
wrist
above elbow
Demyelination +severe axonal loss
Summary motor
Practical approach: Motor 1med (APB) and uln (ADM) comparison
Stimulate at wrist; median and ulnarRecord from APB and ADM (80 mm)Normal lat diff APB-ADM < 1 3 msecNormal lat diff APB-ADM < 1.3 msec
If low APB amplitude, also stimulate in the palmNormal increase < 25%
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Motor: Lumbr I-IOD II
CTS; mainly motor- demo of IOD, lumbr
Uln; 2.7 Med; 4.0
Practical approach: Motor 2med (lumbrical I) and uln (IOD II) comparison
- performed in severe casesStimulate median and ulnar at wrist crest Record between metacarp II and III
Normal diff < 0.7 msec (Tromsö + Normal diff < 0.7 msec (Tromsö + littlitt))< 0.5 msec (B.S < 0.5 msec (B.S KherzriKherzri, K , K LindblomLindblom, BMA), BMA)
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5
4
Motor: corr Medlat-Ulnlat vs lumbr1-IOD230 controls, 30 CTS Tromsö
lub-iod
76543210-1
med
-uln
3
2
1
0
-1
P atient Diagnos is
p n p
n o rm a l
cts
Comparison lumb/IOD is not better than APB/ADM
lumb-IOD
Median nerve, sensoryDemyelination, slowing across CT:
a) dig to wrist or wrist to dig. CV compared to ulnar (IV) or radial (base of thumb)
b) palm to wrist (med and uln)c) 14-7 antidromicd) 14-7 CT tester
Axonal degeneration, general loss of ampl:sensory amplitudes distal to CT lig
Conduction block, amplitude drop across CT:
Sensory: orthodromic dig IV and mixed from palm
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Practical approach: SensoryMedian dig IV and ulnar dig IV comparison
Stimulate wrist median and ulnarRecord base of dig IVgCalculate CV
Normal diff (IV-IV) < 16 m/sec
32 controls, 24-69 y
Sensory: antidromic med-uln
Sensory antidromic med-rad
10
1010
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Antidromic stim of med + rad nerve (ring electrodes) Bactrian sign CTS
normal CTS
Med + Rad stim (ring el), Bactrian sign in CTS
20 uV/div1ms/div
antidromic
normal CTSrad + medrad med
antidromic
orthodromic
CTS
Practical approach: SensoryMedian thumb and radial thumb comparison
Stimulate wrist; median and radialRecord base of thumb (ring el)Di t 10Distance 10 cm
Normal diff < 0.3 ms
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Sensory antidromic 14-7 cm
77
+
Reference values14-7measured to neg peak
Segment 95% limit source
140 mm: 3.5 ms Örebro3 7 ms Johnson3.7 ms Johnson
palm-digIII 1.9 ms Örebro trans- CT 1.6 ms Örebro
Sensory orthodromic, “CT tester”
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NormalT2/T1 = 1T2T1
CTT2/T1 > 1
T2T1
Diagnostic output CT-tester
A i di i 70% ”N i l” 30%Automatic diagnosis 70% ”No signal” 30%
CTS 88%PNP 9%
Normal 3%
CTS, CT tester
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Left
Late
ncy
[ms]
Tra
ce1 10
9
8
7
6
M-latmed
SNCS Medianus Left CV [m/s] Trace4
80706050403020
MNC
SM
edia
nus
L
5
4
3
2
SIDE
s
d
b
only motor
only sensory
Sens CV III
CTS; CT index vs sens CV diff dig 4- 450
40
30
6 5%
CT Tester CT Index cts
3,53,02,52,01,51,0,5
SDI4
_4C
T
20
10
0
-10
24.4%
6.5%
CT tester
CV
um
ed 4
-uln
4
Definitions of CTS(Luca Padua)
• Slight only sensory abnormalies• Moderate sens +motor abnormal• Pronounced no sens responses• Pronounced no sens responses• Very severe no sens or motor responses
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CTS; additional methods
* pron quadr/APB amplp q p* centimetering* ultrasound
N Interosseus antRec Pron quadr
Stim median nerve
rec 45 mm prox linel diiproc styl.radii-
proc styl. ulna
ref
Use of PQ in severe CT69 y trauma, hand drop. Plexus? Focal nerve? PNP?
Stiff pers. Syndr.
APB = 0lumb1 and IOD2
Normal PQ response indicates normal median proximally. CT.Pat has also pnp.
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Median nerve SSS - method
Median nerve centimetering, normal finding
SSS in very mild CTS
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Ultrasound
All pictures with Courtesy
Lisa Hobson-Webb M DLisa Hobson-Webb, M.D.Advanced Fellow in Neuromuscular DiseaseDuke University Medical Center
A Normal Median Nerve
Asymptomatic vs. CTS
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12cmElbow Hand
Imaging TechniqueForearm measurement
Wristmeasurement
Normal median nerve in sagittal plane
Measurement in CTS
D=12cmElbow Hand
Focal enlargementat carpal tunnel
Median nerve insagittal plane
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CommentsComments
• Both sensory (more than one test) and motor nerve should be tested
• Sensitivity and specificity:Sensitivity and specificity:– single ref values (sens)– inter-nerve comparison (spec)– transcarpal tunnel conduction (spec)
• Additional tests to detect:– cond block; motor and sensory (antidromic)
Pooled sensitivity and specificity of EDX techniques for CTS
Pooled Pooledsensitivity specificity
A Median sensory and mixed nerve conduction: wrist and palm segmentcompared to forearm or digit segment 0.85 0.98
B Comparison of median and ulnar sensory conduction between wrist andring finger 0.85 0.97
C Median sensory and mixed nerve conduction between wrist and palm 0.74 0.97
D Comparison of median and ulnar mixed nerve conduction between wristand palm 0.71 0.97
AAEM M&N 2002
p
E Median motor nerve conduction between wrist and palm 0.69 0.98
F Comparison of median and radial sensory conduction between wrist andThumb 0.65 0.99
G Median sensory nerve conduction between wrist and digit 0.65 0.98
H Median motor nerve distal latency 0.63 0.98
I Median motor nerve terminal latency index 0.62 0.94
J Comparison of median motor nerve distal latency (second lumbrical) to theulnar motor nerve distal latency (second interossei) 0.56 0.98
K Sympathetic skin response 0.04 0.52
CTS standards, guidelines, optionsMedian sensory NCS across the wrist (13 cm to 14 cm) (Technique G). If abnormal, compare median
sensory NCS to sensory NCS of one other adjacent sensory nerve in the symptomatic limb (Standard).
If the initial median sensory NCS across the wrist (distance greater than 8 cm) is normal, one of the following studies is recommended:
comparison of median sensory or mixed nerve conduction across the wrist over a short (7 cm to 8 cm) conduction distance (Technique C) with ulnar sensory nerve conduction across the wrist over the same short (7 cm to 8 cm) conduction distance (Technique D) (Standard), or
comparison of median sensory conduction across the wrist with radial or ulnar sensory conduction across the wrist in the same limb (Techniques B and F) (Standard), or
comparison of median sensory or mixed nerve conduction through the carpal tunnel to sensory or mixed NCSs of proximal (fore arm) or distal (digit) segments of the median nerve in the same limb (Technique A) (Standard).
AAEM M&N 2002
( q ) ( )
Motor NCS of the median nerve recording from the thenar muscle (Technique H) and of one other nerve in the symptomatic limb to include measurement of distal latency (Guideline).
Supplementary NCS: comparison of the median motor nerve distal latency (second lumbrical) to the ulnar motor nerve distal latency (second interossei) (Technique J); median motor terminal latency index (Technique I); median motor nerve conduction between wrist and palm (Technique E); median motor nerve compound muscle action potential (CMAP) wrist-to-palm amplitude ratio to detect conduction block; median sensory nerve action potential (SNAP) wrist-to-palm amplitude ratio to detect conduction block; short segment (1 cm) incremental median sensory nerve conduction across the carpal tunnel (Option).
Needle electromyography (EMG) of a sample of muscles innervated by the C5 to T1 spinal roots, including a thenar muscle innervated by the median nerve of the symptomatic limb (Option).
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MOTOR:MOTOR:
APB (full exam – CV, F) ADM (uln only distally)
in case of exceptional situation:in case of exceptional situation:Lumbr I, IOD IIPron quadr, ADMEMG
•• SENSORY:SENSORY:
• Orthodromic method: (rec wrist, calc CV)– med dig 4, uln dig 4 and– med dig 3, uln dig 4– med palm uln palmmed palm, uln palm
• CT tester
• In case of exceptional situation (uln trauma, cut fingers)
– 7-14 antidromic wrist to dig 3– orthodromic thumb to radial and median (Bactrian sign)– digital branch:antidromic to individual digits (tennis, golfer)