Thoracic outlet syndrome

Anatomy

Compression of the neurovascular bundle can result from a variety of different pathologies
- Anomalous ribs - cervical ribs predispose patients to develop TOS after whiplash injuries
- Congenital cervical fibro-cartilaginous bands, associated with incomplete cervical ribs
- Muscular anomalies narrowing the space between anterior and middle scalenes
- Injury - chronic inflammatory change due to trauma

Neurogenic (95%) - compression of brachial plexus
- Presentation
  - Neurological thoracic outlet syndrome (nTOS) - upper extremity pain, paraesthesia, dysaesthesia, numbness, weakness
    - Classically in an ulnar distribution
    - Raising arms overhead tends to worsen symptoms
    - 9:1 women:men
- Investigation
  - CXR (cervical rib)
  - CT/MRI can be useful, primarily to exclude other pathologies
  - Scalene block - remission of symptoms after block can predict patients who will improve after surgery
- Treatment
  - PT, OT, weight loss
  - Analgaesics, anti-inflammatories
  - If no improvement after 8/52 - surgery considered, however the recurrence rate is quite high with time, and surgery should really only be for those with disabling symptoms or progressive neurology
- Surgery
  - Transaxillary approach favoured
  - NTOS success is as high as 93% immediately, and 70% at 10 years
Venous (4%) - compression of subclavian vein
- vTOS
  - Swelling/cyanosis without DVT
- Generally thrombolysis and early surgical decompression have good long-term outcomes
Arterial (1%)
- aTOS
  - Claudication, coolness, venous thromboembolism
- Generally intervene. aTOS is nearly always associated with a correctable bony abnormality.