Thoracic outlet syndrome

Question 1

What is thoracic outlet syndrome?

Answer 1

• 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

Question 2

Symptoms and signs divisions

Answer 2

• Can be neurological TOS
• Arterial TOS
• Venous TOS

Question 3

When does TOS usually occur?

Answer 3

• 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

Question 4

Pathophys of TOS

Answer 4

• 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

Question 5

Ways brachial plexus and subclavian artery can be compressed

Answer 5

• Hypertrophy of scalene muscles
• Abnormal 1st rib
• Cervical rib
• Previous clavicle #

Question 6

Ways subclavian vein can be compressed

Answer 6

• Costoclavicular ligament presence
• = reduced costoclavicular space –> vTOS due to positional venous obstruction

Question 7

What is a cervical rib

Answer 7

• Additonal rib
• Arises from 7th cervical vertebrae
• Can be partial or complete
• Majority patients unaware and symptomless - no intervention needed

Question 8

RF TOS

Answer 8

• Recent trauma
• Repetitive motion occupations
• Athletes - repetitive arm motions eg swimming or racquet sports and bodybuilders
• Anatomical variation

Question 9

Compression of brachial plexus symptoms

Answer 9

• Paraesthesia +/- motor weakness
• Often ulnar distrubution
• May be muscle wasting and pain can radiate to neck and upper back

Question 10

Venous TOS symptoms

Answer 10

• Can lead to DVT and extremity swelling - Paget Schrotter syndrome
• If untreated severe - prominent veins over shoulder due to collateralisation

Question 11

Arterial TOS symptoms

Answer 11

• Claudication or
• Acute limb ischaemia

Question 12

Examination for TOS

Answer 12

• Assess for weakness/numbness
• Swelling/tenderness
• Limb ischaemia?
• Often tender over scalene muscles

Question 13

Special test names for TOS

Answer 13

• Adsons manoeuvre
• Roo’s test
• Elveys test

Question 14

Adsons manoeuvre

Answer 14

• 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

Question 15

Roos test

Answer 15

• 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

Question 16

Elveys test

Answer 16

• Extend arm to 90 degrees
• Elbow extended
• Wrist dorsiflexed
• Tilt patients ear to each shoulder
• Loss of radial pulse or worsening symptoms = TOS

Question 17

Investigations for TOS - initial

Answer 17

• Bloods - FBC, clotting
• CXR - identify bony abnormalities eg cervical ribs

Question 18

Further investigations for TOS

Answer 18

Venous or arterial:
* Venous and arterial duplex US - at rest and in stress positions
* CT or MRI imaging or venogram

Neurogenic:
* Nerve conduction studies - rule out carpal tunnel and cubital tunnel syndrome

Question 19

nTOS management

Answer 19

• Physiotherapy - 6 months to improve mobility in neck and shoulder, strengthen surrounding muscles and relax scalene
• Botulinum toxin injections can help relax scalene - aid physiotherapy

Question 20

vTOS management

Answer 20

• Thrombolysis and anticoagulation
• Most cases eventually need surgical management
• = decompress thoracic outlet with venoplasty/reconstruction or placement of venous stent

Question 21

aTOS management

Answer 21

• ALI - vascular input urgent, may need embolectomy
• Most cases can be managed elective surgery

Question 22

Surgical procedures used in TOS

Answer 22

• Supraclavicular or transaxillary approach to decompression
• Excise first or cervical rib
• Restrictive bands can be released too (or even anterior scalene)

Question 23

When is surgery considered for TOS

Answer 23

• Conservative measures failed
• Anatomical variations requiring correction

Question 24

Complications surgery for TOS

Answer 24

• Neurological or vascular damage
• Haemothorax
• Pneumothorax
• Chylothorax - esp on left, thoracic duct is within outlet and risk of damage

Question 24

Complications of TOS

Answer 24

• Permanent nerve damage
• Aneurysmal dilation of subclavian artery –> embolisation
• Loss of limb function

Question 24

Prognosis TOS

Answer 24

• Variable
• Vascular TOS responds well to surgery
• Neurogenic not as well