Thoracic Outlet

Question 1

What are the Scher classes for aTOS?

Answer 1

0 - asymptomatic, no tx except high performance athletes, monitor 1 - subclavian artery stenosis and mild dilatation but no intimal injury - decompression of thoracic outlet and repeat imaging 2 - subclavian aneurysm with mural thrombus - decompression and recon of subclavian artery 3 - thrombosis or distal embolization - thrombectomy/lysis, decompression, recon of subclavian artery

Question 2

Which Scher classes require supraclavicular approach?

Answer 2

2 and 3 because subclavian needs to be reconstructed

Question 3

How long after venous thrombolysis should you perform vTOS decompression surgery?

Answer 3

Same admission, even as early as 4h after

Question 4

Which conduit has the best patency for arterial bypass after TOS decompression?

Answer 4

PTFE (small single institution studies) > Dacron > vein. Thought to be because its a short conduit with repetitive stress.

Question 5

What percentage of TOS is neurogenic, venous or arterial

Answer 5

95% 3% 1%

Question 6

Which 3 anatomic spaces pertain to TOS?

Answer 6

Anterior scalene - art, brachial plexus Costoclavicular space - vein Pec minor space

Question 7

Which nerve goes lateral to medial in the supraclavicular dissection

Answer 7

Phrenic

Question 8

Which muscle belly does the long thoracic nerve pierce?

Answer 8

Middle scalene

Question 9

Which nerve roots does long thoracic arise from?

Answer 9

C5,6,7

Question 10

What root does dorsal scapular nerve arise from?

Answer 10

C5, usually don’t see in supraclavicular dissection, descends lateral to middle scalene

Question 11

How do you get horners after supraclavicular TOS decompression?

Answer 11

Cautery used to excise scalene muscles, current may reach the transverse process origins and damage cervical sympathetic chain

Question 12

What is the difference between a cervical rib and anomalous 1st rib?

Answer 12

Cervical rib arises from C7, 1st rib from T1

Question 13

What is the most common cause of nTOS?

Answer 13

Neck trauma - whiplash

Question 14

Name 7 history, signs and symptoms in nTOS?

Answer 14

Neck trauma 80%, occupation, occipital headache, trap/neck/chest/shoulder pain, hand symptoms, MSK interventions, Raynauds symptoms (cold or color changes as a result of sympathetic nerve compression)

Question 15

Name 3 physical exam tests for nTOS

Answer 15

1-Adson, elevate/externally rotate arm feel for radial pulse as neck laterally rotate and flex ipsilaterally while inhaling. Not at all validated. 2-EAST/Roos - arms and elbows at 90 degrees, open and close for 3 min 3- Elvey - abduct arms to 90, dorsiflex both wrists,laterally flex head on each side. 4 - Upper limb tension test - just like straight leg raise for lower extremity

Question 16

What are the boundaries of the costoclavicular space where subclavian vein is?

Answer 16

Subclavius/costoclavicular ligament medial Ant scalene lateral 1st rib inferior Clavicle superior

Question 17

What type of TOS is more common in men than women?

Answer 17

Venous

Question 18

What type of TOS more common in athletes?

Answer 18

Venous

Question 19

What symptoms do patients with venous TOS present with?

Answer 19

Swelling, cyanosis, pain w exercise

Question 20

What is McCleery syndrome?

Answer 20

Upper extremity swelling without thrombosis due to compression of subclavian vein

Question 21

What is the most common presentation of arterial TOS

Answer 21

Microemboli to hand causing ischemia symptoms

Question 22

What is pagett’s von schrotters?

Answer 22

Eponym for venous TOS, renamed “effort thrombosis”

Question 23

Which structures impact venous TOS?

Answer 23

costoclavicular space - anterior scalene, clavicle/subclavius muscle, fibrous costocoracoid ligament, 1st rib

Question 25

Which arm is most likely involved in venous TOS?

Answer 25

Dominant - from overuse injury

Question 26

What is the risk of PE from subclavian-axillary vein thrombosis?

Answer 26

\< 10%

Question 27

What is the DASH questionnaire?

Answer 27

Disability of Arm Shoulder and Hand - to evaluate QoL after UE venous thrombosis

Question 28

Should you thrombolyse venous clots due to vTOS?

Answer 28

Some studies show equal 5 year patency with catheter directed thrombolysis + surgical decompression vs. anticoagulation + surgical decompression

Question 29

What time frame should you thrombolyse patients with thrombosed veins in vTOS

Answer 29

Within 14 days of symptoms have best results

Question 30

1) What nerve roots make up the brachial plexus? 2) What are the trunks?

Answer 30

1) C5 - T1 2) Upper: C5/C6, Mid C7, Lower C8/T1

Question 31

How many types of congenital bands and ligaments are there in the scalene triangle?

Answer 31

Types 1 - 9

Question 32

Give an example of a congenital band or ligament within the scalene triangle.

Answer 32

type 5 = scalene minimus muscle

Question 33

What are 2 histologic changes are seen in the scalene muscles of nTOS patients?

Answer 33

1) predominance of type 1 (slow twitch) fibers and atrophy of type 2 (fast twitch) fibers 2) 2 fold increase/thickening of connective tissue matrix

Question 34

Name 8 differentials for nTOS

Answer 34

1) fibromyositis - localized tenderness/nodules 2) ulnar nerve entrapment - ulnar nerve distribution, positive NCS 3) carpal tunnel syndrome - median nerve distribution, positive NCS 4) rotator cuff tendonitis - localized tenderness over biceps tendon/shoulder 5) brachial plexus injury - not positional, positive NCS 6) cervical disc disease - CT/MRI 7) cervical arthritis - spine xrays 8) cervical spine strain/sprain - posttraumatic neck pain, better with time conservative

Question 35

What is the clinical diagnostic criteria for nTOS?

Answer 35

UE symptoms beyond distribution of single peripheral nerve, present for at least 12 weeks and meet at least 1 of the following in 4 of 5 categories 1) principal: pain, numbness 2) symptom characteristics - exacerbated by elevated arm, prolonged keyboard/repetitive strain 3) history: after trauma, cervical rib, prev c-spine surgery without improvement 4) physical exam: local tender on scalene/subcoracoid, objectively weak hand grip 5) maneuvers: positive ULTT, positive 3 minute EAST (elevate with opening/closing fists)

Question 36

What is the most common anatomic anomaly associated with aTOS? What are 4 other causes?

Answer 36

Most common - cervical rib. Others: anamolous first rib, fibrocartilagenous vand, clavicular fracture, enlarged C7 transverse process