Thoracic outlet syndrome (TOS) consists of a group of clinical disorders caused by compression of the neurovascular bundle at the thoracic outlet.
TOS is classified into three broad groups based on the neurovascular structure which is compromised: neurogenic thoracic outlet syndrome {NTOS) involves compression of the brachial plexus; arterial TOS (subclavian/axillary artery) or venous TOS (subclavian/axillary vein).
This is a retrospective study of patients diagnosed with true neurogenic thoracic outlet syndrome (NTOS) following neurophysiological testing in the Royal Preston Hospital. The Royal Preston Hospital provides Neuroscience Specialist Services for patients the catchment that encompasses Lancashire and South Cumbria.
A total of 38 patients were confirmed with a diagnosis of NTOS over a thirteen-year period between September 2005 – April 2018, equivalent to three new cases per year. NTOS is calculated to have an incidence of around 1.8 cases per million per year in the catchment population. The age range of cases was from 16-84 years, with a mean age of 46.7years. The mean age of 46.7 years is comparable to previous estimates of an age of onset within the fourth decade and a mean age of 40.7 years. The majority of referrals were from surgical specialities (58%). Eighty nine (89%) of the cases were females which is comparable to the gender differences of 9:1 in the literature.
Epidemiologically, NTOS is an uncommon disorder rarely encountered by most clinicians. A lot of referrals are received each year in Neurophysiology for query Thoracic outlet syndrome. Majority of referrals would not show NTOS, but one should expect to see about 2-3 genuine case every year. It is known that most patients with TOS will either present with T-NTOC or Vascular TOS. It is very rare to have both Neurogenic and Vascular TOS. Patients would usually have either one or the other. This is likely related to anatomy. Many referrals for query TOS are referred by vascular surgeons and other clinical practitioners who have elicited a positive Adson’s test. What is not familiar is that most patients with Vascular TOS would not have NTOS.
