Thoracic outlet syndrome (TOS) is a rare condition (1-3 per 100,000) caused by neurovascular compression at the thoracic outlet and presents with arm pain and swelling, arm fatigue, paresthesias, weakness, and discoloration of the hand. TOS can be classified as neuro-genic, arterial, or venous based on the compressed structure(s). Patients develop TOS secondary to congenital abnormalities such as cervical ribs or fibrous bands originating from a cervical rib leading to an objectively verifiable form of TOS. However, the diagnosis of TOS is often made in the presence of symptoms with physical examination findings (disputed TOS). TOS is not a diagnosis of exclu-sion, and there should be evidence for a physical anomaly that can be corrected. In patients with an identifiable narrowing of the thoracic outlet and/or symptoms with a high probability of thoracic outlet neurovascular compression, diagnosis of TOS can be established through history, a physical examination maneuvers, and imaging. Neck trauma or repeated work stress can cause scalene muscle scaring or dislodging of a congenital cervical rib that can compress the brachial plexus. Nonsurgical treatment includes anti-inflammatory medi-cation, weight loss, physical therapy/strengthening exercises, and botulinum toxin injections. The most common surgical treatments include brachial plexus decompression, neurolysis, and scalenotomy with or without first rib resection. Patients undergoing surgical treatment for TOS should be seen postoperatively to begin passive/assisted mobilization of the shoulder. By 8 weeks postoperatively, patients can begin resistance strength training. Surgical treatment complications include injury to the subclavian vessels potentially lead-ing to exsanguination and death, brachial plexus injury, hemothorax, and pneumothorax. In this review, we outline the diagnostic tests and treatment options for TOS to better guide clinicians in recognizing and treating vascular TOS and objectively verifiable forms of neurogenic TOS.Level of evidence: Narrative Review (c) 2022 Published by Elsevier Inc. on behalf of Journal of Shoulder and Elbow Surgery Board of Trustees.
