Thoracic outlet syndrome (TOS) is a rare disease with a spectrum of symptoms, typically severe pain, resulting from compression or irritation of arteries, nerves, or veins. This can happen in one or more of the brachial plexus (nerves), subclavian vein, or subclavian artery. This occurs in the body region known as the thoracic outlet—the area between the neck and the underarm (axilla) below the collarbone (clavicle). Compression of a nerve or blood vessel produces different clinical impacts. The disease and symptoms result in significant disability and a profoundly diminished quality of life.
Neurogenic TOS (NTOS) results from compression and/or irritation of the brachial plexus, a complex array of nerves. NTOS is the most common form of TOS, occurring in greater than 90% of patients (Ref 1).
There can be a wide variety of symptoms, but the most common is severe pain. Pain occurs in the neck, upper chest and/or an arm. Patients may also experience altered sensation including tingling (paresthesias) or numbness (decreased sensation) most commonly in an arm. Arm weakness and diminished coordination of the hand may also present. Some patients will have skin discoloration or abnormal temperature sensation in an arm. Symptoms are frequently exacerbated with use of an arm.
Vascular TOS (VTOS) occurs when the subclavian vein (venous TOS) or artery (arterial TOS) are compressed. Symptoms are caused by blood clots (subclavian vein thrombosis) and/or narrowing of body spaces (stenosis). Symptoms affect the arm and include swelling, heaviness or aching, and cyanosis (bluish-purple skin colour). Veins in the upper chest and shoulder may be prominent and distended. Arterial TOS symptoms include arm fatigue, lack of blood in the hand (distal ischemia), reduced blood flow to fingers (Raynaud’s phenomenon), or stroke.
TOS is usually caused by a combination of two factors:
- Abnormal anatomy that creates compression in the thoracic outlet and
- Injury to the thoracic outlet area
Anatomic abnormalities may be obvious, such as an additional rib in the neck or an abnormality in the spine at the base of the neck. Some abnormalities may be subtle and difficult to detect, such as abnormalities within neck muscles (scalene muscles) located on either side of the front of the throat or ligaments within this region. The injuries required to trigger symptoms may also be severe, such as a car collision, or subtle, such as a mild injury from arm activity.
TOS is rare, affecting 2-3 people per 100,000 (Ref 2) . The required specialty and clinical experience are underdeveloped in Canada. There are no clinics or specialists in Canada who focus exclusively or primarily on TOS. An international group of experts reported in 2020 on a consensus for TOS diagnosis and treatment; no Canadian clinicians were involved (Ref 3) . Patients frequently experience a diagnostic odyssey, misdiagnosis, conflicting therapies from varied and multiple health professionals and specialties, and recommended treatments absent of clinical specialty knowledge of TOS treatment and care. Many patients receive incomplete surgeries which worsen nerve pain. For some, treatments in Canada result in permanent damage. For patients who fail to improve, recommended treatment often shifts to opioid-driven pain management, mental health supports, and disability income support programs. Faced with no other options, some TOS patients travel at personal expense to specialty clinics in the United States to access TOS specialists to improve their condition and lives.
Treatments for Thoracic Outlet Syndrome
Many patients can be treated for TOS without surgery. Common treatments include ultrasound-guided injections in the neck and upper chest region, medications, and physical therapy. Often, a combination of these treatments provides optimal results. Making the correct TOS diagnosis is key to successful treatment. Ideally, your care team will customize a diagnostic program specifically for you using techniques such as CT scans, high-resolution MRI, vascular studies, and nerve-conduction studies.
Your doctor may recommend surgery to treat your TOS. This may include decompression surgery, vein repair, or rarely artery repair.
Surgery for TOS may also involve:
- Removal of the first thoracic rib
- Partial removal of the scalene muscles
- Removal of other tissues or scarring which may be causing compression of the thoracic outlet
- If present, removal of an additional rib located in the lower neck located in the spine, cervical rib
- Release of the pectoralis minor muscle
- Reconstruction of the subclavian vein or artery
The goal of surgery is to take pressure off the nerves and allow the body to use its own healing process in helping the nerve to recover. The vast majority of patients improve significantly after surgery.
Footnotes and References
1. Jones MR, Prabhakar A, Viswanath O, et al.
Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment. Pain Ther. 2019;8(1):5-18.
doi:10.1007/s40122-019-0124-2.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6514035/
2. Karl A. Illig, Eduardo Rodriguez-Zoppi, Travis Bland, Mayssan Muftah, Elodie Jospitre,
The Incidence of Thoracic Outlet Syndrome, Annals of Vascular Surgery, Volume 70, 2021,
Pages 263-272, ISSN 0890-5096, https://doi.org/10.1016/j.avsg.2020.07.029.
(https://www.sciencedirect.com/science/article/pii/S089050962030621X)
3. J. Westley Ohman, Stephen J. Annest, Ali Azizzadeh, Bryan M. Burt, Francis J. Caputo, Colin Chan, Dean M. Donahue, Julie A. Freischlag, Hugh A. Gelabert, Misty D. Humphries, Karl A. Illig, Jason T. Lee, Ying Wei Lum, Richard D. Meyer, Gregory J. Pearl, Erin F. Ransom, Richard J. Sanders, Joep A.W. Teijink, Patrick S. Vaccaro, Marc R.H.M. van Sambeek, Chandu Vemuri, Robert W. Thompson
Evaluation and treatment of thoracic outlet syndrome during the global pandemic due to
SARS-CoV-2 and COVID-19, Journal of Vascular Surgery, Volume 72, Issue 3, 2020, Pages 790-
798,
ISSN 0741-5214, https://doi.org/10.1016/j.jvs.2020.05.048.