Key points

• Thoracic outlet syndrome (TOS) can be neurogenic, venous or arterial

• Neurogenic TOS is the commonest presentation, seen in 90% of cases

• Arterial presentation is very rare but may be more dramatic with digital gangrene

• TOS is due to extrinsic compression from fibrous bands, cervical rib or first rib

• Physical examination may be helpful with the Roos test being positive in the majority

• Plain X-rays, Duplex and magnetic resonance angiography (MRA) may be helpful but the diagnosis is mainly clinical

• Electrophysiology testing is non-specific although median antebrachial nerve response has recently shown to be useful

• Removal of fibrous bands, cervical ribs and the first rib may be needed along with anterior scalenectomy

• Arterial reconstruction of the subclavian artery may be required

Introduction

TOS is one of the most controversial clinical entities in ­medicine. This is partly because there is no definitive diagnostic test and debate ­continues as to whether the syndrome even really exists in some of its forms! Its incidence has been estimated at 5:100,000 per year in the UK although the true figure is still unknown.

The thoracic outlet is the region at the top of the rib cage between the base of the neck and the axilla through which the brachial plexus and the subclavian vessels travel. The first channel is the interscalene triangle, which is bordered by the scalenus anterior, scalenus medius and the medial border of the first rib (Figure 11.1).