The subclavian artery in 16 patients with complete cervical ribs.

In a series of 16 patients presenting with symptoms due to the presence of a complete cervical rib, 8 complained of neurological symptoms only and 8 presented with major vascular symptoms. There were 21 complete cervical ribs in this series, 5 patients having bilateral cervical ribs, and these were excised. At operation particular attention was paid to the anatomy and pathology of the subclavian artery in relation to the cervical rib. Two anatomical variants were present. In type A cervical rib (16 cases) the subclavian artery crossed the first rib medial to the exostosis and all patients with major vascular symptoms were in this category. In type B (5 cases) the subclavian artery crossed the first rib lateral to the exostosis and symptoms, when present, were neurological rather than vascular. The two groups can be distingushed clinically and this may be of prognostic value. Post-stenotic dilatation of the subclavian artery acompanied 15 of the 21 complete cervical ribs and was attributed to compression of the artery between the cervical rib and the anterior scalene muscle. In 8 instances the post-stenotic dilatation was complicated by aneurysm and peripheral thrombo-embolism and this was regarded as a secondary phenomenon due to intermittent trauma at cost-clavicular level. A follow-up of up to 9 years would indicate that post-stenotic dilatation of mild or moderate degree is adequately treated by resection of the cervical rib and exostosis on first rib. When an aneurysm is present with localised disruption of the arterial wall with mural thrombus, it is necessary also to excise the aneurysm for, otherwise, there is a risk of further thrombo-embolic episodes.