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R9 > Chapter 120 - TOS introduction > Flashcards

Chapter 120 - TOS introduction Flashcards

1
Q

Incidence of the three types of TOS

A

nTOS: 95%
vTOS: 3%
aTOS: 1%

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2
Q

Etiology of TOS subtypes

A

nTOS: neck trauma, fall, work related
vTOS: repetitive overhead shoulder movement, coagulopathy
aTOS: cervical rib, anomalous first rib, congenital band

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3
Q

Predisposing factor of TOS subtyes

A

nTOS: cervical rib, congenital band, scalene triangle muscle variation
vTOS: congenital narrowing of costoclavicular space by costoclavicular ligament or subclavian tendon
aTOS: cervical rib, anomalous first rib

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4
Q

Pathology of TOS subtype

A

nTOS: comperssion
vTOS: stenosis +/- thrombosis
aTOS: stenosis, thrombosis/aneurysm +/- thrombi

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5
Q

Symptoms of TOS subtypes

A

nTOS: pain, paresthesia, weakness, neck pain, occipital headache, Raynaud, chest pain (pec minor syndrome)
vTOS: arm swelling, cyanosis, pain
aTOS: pain, parethesia, pallor, coldness, digital ischemia, arm claudication, neck/shoulder symptoms

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6
Q

Physical finding of TOS subtypes

A

nTOS: positive response to provocative maneuvers, tenderness over scalene, pec minor
vTOS: arm swelling, cyanosis, pain
aTOS: decreased pulses, color change, ischemic tips and emboli

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7
Q

Diagnostic test for TOS subtypes

A

nTOS: duplex, scalene muscle block, MRI, pec minor block, EMG/NCV/MAC measurement
vTOS: duplex, venogram
aTOS: neck xray, duplex, arteriogram, digital pressure, arteriography

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8
Q

epidemiology of TOS

A

most 20-50 age
< 5% teen
10% > age 50

vTOS: female 70%
nTOS: 2:1 male more

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9
Q

Spaces of the thoracic outlet

A

1) Scalene triangle
2) costoclavicular space
3) pectoralis minor space

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10
Q

Brachial plexus origin

A

Nerve roots C5 to T1

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11
Q

Where does the brachial plexus form 3 trunks

A

in scalene triangle

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12
Q

Where does the brachial plexus form division and cords

A

proximal to pec minor space

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13
Q

Phrenic nerve origin

A

C4 mostly

some C3 and C5

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14
Q

Percentage of phrenic nerves that are single vs double or triple

A

87% single

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15
Q

Where does the phrenic descend in relation to anterior scalene

A

Later to medial 84%

remains lateral

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16
Q

Long thoracic nerve origin

A

C6 mostly

contribution from C5 and C7

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17
Q

Long thoracic nerve course

A

C5 and C6 go through middle scalene

C7 comes below middle scalene to join the other two branches

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18
Q

Dorsal scapular nerve origin

A

C5

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19
Q

Course of the dorsal scapular nerve

A

through the cephalic portion of middle scalene

descend lateral to muscle

20
Q

Cervical sympathetic chain location

A

over transverse process of cervical vertebrae

close to origin of anterio and middle scalene

21
Q

Variations of the scalene muscle

A

1) splitting anterior scalene around C5, C6 (21% of nTOS)
2) Scalene minimus muscle - from transverse process of lower cervical vertebrae runs in front of C8, T1 then behind subclavian artery –> inserts on first rib/sibson fascia (25-55%)
3) interdigitating muscle fibers - between anterior and middle scalene (75% of nTOS)
4) narrow vs wide scalene triangle (0.3-2.0 cm); nerve root emerg lower in wide triangle; nTOS have narrow triangle
5) congenital bands 63%
6) phrenic nerve: usually posterior to subclavian vein but 5-7% runs anterior (cause vTOS)
7) variation in medial position of subclavian vein close to costoclavicular ligament

22
Q

Anomous first rib and cervical rib incidence and gender

A

0.76% and 0.74%
Female : male
7:3

23
Q

Cervical rib connection with first rib

A

30% true joint
70% fibrous band

can line within middle scalene muscle

24
Q

Scalene triangle boarders

A

Anterior scalene
Middle scalene
First rib

25
Q

Costoclavicular space boarders

A

Clavicle
Subclavius muscle
Costoclavicular ligament
First rib

26
Q

Pec minor space borders

A

pec minor
ribs of chest wall

(axillary compression syndrome)

27
Q

rate of pec minor syndrome in recurrent nTOS

A

75%

28
Q

First introduction of transaxillary first rib resection

A

1966 Roos

29
Q

Pathologic finding in nTOS

A

1) development anomaly in TO with fibrosis of scalene

2) conversion of muscle from fast twitch to slow twitch

30
Q

Physical examinations for nTOS

A

1) Adson test
2) elevated arm stress test (EAST, Roos test)
3) Modified upper limb tension test (Elvey test)

31
Q

Adson test

A

1) palpate radial puls
2) extend, abduct and external rotate arm
3) rotate and lateral flex neck to ipsilateral side
4) positive test = decrease radial pulse

32
Q

EAST/Roos test

A

1) seated with arms abducted 90 degree in external rotation
2) elbow flex at 90 degree
3) head in neutral position
4) open close hand x 3 min

if able to perform then high NPV for nTOS

33
Q

Elvey test

A

1) abduct both arms 90 degree with elbow extended
2) dorsiflex both wrist
3) positive if symptoms on ipsilateral side
4) flex neck on each side
5) test positive if symptoms on contralateral side

34
Q

Key points about Adson test

A

only objective test

50% normal individuals test positive anyway

35
Q

Anterior scalene muscle block

A

Injection with 1% lidocaine into the anterior scalene muscle

36
Q

First description of Paget-Schroetter syndrome

A

Paget 1875

von Schroetter 1884

37
Q

McCleery syndrome

A

symptoms characteristic of vTOS without venous thrombosis

38
Q

Characteristics of VTOS

A

primary thrombosis of the axillo-subclavian vein secondary to compressive symptoms from thoracic outlet pathology

39
Q

Percentage of vTOS that have first rib fractures

A

43%

40
Q

Rate of pulmonary embolism in nTOS with DVT

A

12%

41
Q

vTOS symptoms and frequency

A

1) arm swelling 93%
2) cyanosis 77%
3) pain with exercise 66%
4) minimal symptoms 8%

42
Q

Duplex for vTOS sen and spe

A

Sen 78-100%
spe 82-100%

must do with provocative maneuvers

43
Q

Anomalies in aTOS and frequency

A

1) cervical rib 60%
2) anomalous first rib 18%
3) fibrocartilaginous band 15%
4) clavicular fracture 6%
5) enlarged C7 transverse process 1%

44
Q

False negative rate of conventional angio in diagnosing aTOS

A

32% in supine position

45
Q

Rate of coexisting nTOS with aTOS

A

5%

46
Q

Medial antebrachial cutaneous (MAC) nerve

A

lowest branch of inferior trunk of the brachial plexus

most sensitive to compression

R9 (200 decks)

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