Thoracic Outlet Flashcards
What are the Scher classes for aTOS?
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
Which Scher classes require supraclavicular approach?
2 and 3 because subclavian needs to be reconstructed
How long after venous thrombolysis should you perform vTOS decompression surgery?
Same admission, even as early as 4h after
Which conduit has the best patency for arterial bypass after TOS decompression?
PTFE (small single institution studies) > Dacron > vein. Thought to be because its a short conduit with repetitive stress.
What percentage of TOS is neurogenic, venous or arterial
95% 3% 1%
Which 3 anatomic spaces pertain to TOS?
Anterior scalene - art, brachial plexus Costoclavicular space - vein Pec minor space
Which nerve goes lateral to medial in the supraclavicular dissection
Phrenic
Which muscle belly does the long thoracic nerve pierce?
Middle scalene
Which nerve roots does long thoracic arise from?
C5,6,7
What root does dorsal scapular nerve arise from?
C5, usually don’t see in supraclavicular dissection, descends lateral to middle scalene
How do you get horners after supraclavicular TOS decompression?
Cautery used to excise scalene muscles, current may reach the transverse process origins and damage cervical sympathetic chain
What is the difference between a cervical rib and anomalous 1st rib?
Cervical rib arises from C7, 1st rib from T1
What is the most common cause of nTOS?
Neck trauma - whiplash
Name 7 history, signs and symptoms in nTOS?
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)
Name 3 physical exam tests for nTOS
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
What are the boundaries of the costoclavicular space where subclavian vein is?
Subclavius/costoclavicular ligament medial Ant scalene lateral 1st rib inferior Clavicle superior
What type of TOS is more common in men than women?
Venous
What type of TOS more common in athletes?
Venous
What symptoms do patients with venous TOS present with?
Swelling, cyanosis, pain w exercise
What is McCleery syndrome?
Upper extremity swelling without thrombosis due to compression of subclavian vein
What is the most common presentation of arterial TOS
Microemboli to hand causing ischemia symptoms
What is pagett’s von schrotters?
Eponym for venous TOS, renamed “effort thrombosis”
Which structures impact venous TOS?
costoclavicular space - anterior scalene, clavicle/subclavius muscle, fibrous costocoracoid ligament, 1st rib
Which arm is most likely involved in venous TOS?
Dominant - from overuse injury
What is the risk of PE from subclavian-axillary vein thrombosis?
< 10%
What is the DASH questionnaire?
Disability of Arm Shoulder and Hand - to evaluate QoL after UE venous thrombosis
Should you thrombolyse venous clots due to vTOS?
Some studies show equal 5 year patency with catheter directed thrombolysis + surgical decompression vs. anticoagulation + surgical decompression
What time frame should you thrombolyse patients with thrombosed veins in vTOS
Within 14 days of symptoms have best results
1) What nerve roots make up the brachial plexus?
2) What are the trunks?
1) C5 - T1
2) Upper: C5/C6, Mid C7, Lower C8/T1
How many types of congenital bands and ligaments are there in the scalene triangle?
Types 1 - 9
Give an example of a congenital band or ligament within the scalene triangle.
type 5 = scalene minimus muscle
What are 2 histologic changes are seen in the scalene muscles of nTOS patients?
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
Name 8 differentials for nTOS
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
What is the clinical diagnostic criteria for nTOS?
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)
What is the most common anatomic anomaly associated with aTOS? What are 4 other causes?
Most common - cervical rib. Others: anamolous first rib, fibrocartilagenous vand, clavicular fracture, enlarged C7 transverse process
