Thoracic outlet syndrome Flashcards
1
Q
What is thoracic outlet syndrome?
A
- Clinical features that arise due to compression of NV bundle within thoracic outlet
- Thoracic outlet - apex of axilla, opening between clavicle first rib and scapula
- Nerves can become compressed here between bones
2
Q
Symptoms and signs divisions
A
- Can be neurological TOS
- Arterial TOS
- Venous TOS
3
Q
When does TOS usually occur?
A
- Hyperextension injuries
- Repetiitve stress injuries eg work-related when working overhead
- External compressing factors eg poor posture
- Can also be secondary to anatomical abnormalities eg cervical rib
4
Q
Pathophys of TOS
A
- Brachial plexus and subclavian artery pass through scalene triangle
- Subclavian vein passess anterior to anterior scalene
- Brachial plexus can be compressed between anterior and middle scalenes or against 1st or cervical rib
- Typically lower cord irritated
5
Q
Ways brachial plexus and subclavian artery can be compressed
A
- Hypertrophy of scalene muscles
- Abnormal 1st rib
- Cervical rib
- Previous clavicle #
6
Q
Ways subclavian vein can be compressed
A
- Costoclavicular ligament presence
- = reduced costoclavicular space –> vTOS due to positional venous obstruction
7
Q
What is a cervical rib
A
- Additonal rib
- Arises from 7th cervical vertebrae
- Can be partial or complete
- Majority patients unaware and symptomless - no intervention needed
8
Q
RF TOS
A
- Recent trauma
- Repetitive motion occupations
- Athletes - repetitive arm motions eg swimming or racquet sports and bodybuilders
- Anatomical variation
9
Q
Compression of brachial plexus symptoms
A
- Paraesthesia +/- motor weakness
- Often ulnar distrubution
- May be muscle wasting and pain can radiate to neck and upper back
10
Q
Venous TOS symptoms
A
- Can lead to DVT and extremity swelling - Paget Schrotter syndrome
- If untreated severe - prominent veins over shoulder due to collateralisation
11
Q
Arterial TOS symptoms
A
- Claudication or
- Acute limb ischaemia
12
Q
Examination for TOS
A
- Assess for weakness/numbness
- Swelling/tenderness
- Limb ischaemia?
- Often tender over scalene muscles
13
Q
Special test names for TOS
A
- Adsons manoeuvre
- Roo’s test
- Elveys test
14
Q
Adsons manoeuvre
A
- Palpate radial pulse on affected side - arm initially abducted 30 degrees
- Then ask patient to turn head and look at the affected sides shoulder
- Fully abduct, extend and laterally rotate shoulder - any reduction/loss of pulse = +ve
15
Q
Roos test
A
- Abduct and externally rotate shoulder on affected side to 90 degrees
- Bend elbow to 90 degrees
- Then ask patient to open and close hands slowly over 3 min period
- Worsening symptoms develop if TOS presen
16
Q
Elveys test
A
- Extend arm to 90 degrees
- Elbow extended
- Wrist dorsiflexed
- Tilt patients ear to each shoulder
- Loss of radial pulse or worsening symptoms = TOS
17
Q
Investigations for TOS - initial
A
- Bloods - FBC, clotting
- CXR - identify bony abnormalities eg cervical ribs
22
Q
Surgical procedures used in TOS
A
- Supraclavicular or transaxillary approach to decompression
- Excise first or cervical rib
- Restrictive bands can be released too (or even anterior scalene)
