Summary Thoracic outlet syndrome is a neurovascular disorder resulting from compression of the brachial plexus and/or subclavian vessels in the interval between the neck and axilla. Diagnosis can be suspected clinically with specific provocative tests and supplemented with radiographs or vascular studies. showing anatomic causes of compression. Treatment may be nonoperative or include surgical decompression or a vascular procedure depending on the specific etiology. Epidemiology Incidence 1-2% of the population Demographics females > males (3:1) tend to be thin with long necks and drooping shoulders age 20-60 Etiology Type neurogenic is most common (95%) vascular may be venous (4%) or arterial (< 1%) more common in athletic males compared to athletic females Pathophysiology most cases are thought to stem from anatomic predisposition with superimposed neck trauma (acute or chronic repetitive stress) anatomically, can be organized into soft tissue (70%) and osseous (30%) abnormalities soft tissue scalene muscle abnormalities login to view 8 more bullets anomalous ligaments or bands login to view 4 more bullets soft tissue tumors login to view 6 more bullets abnormal pectoralis minor osseous cervical rib login to view 7 more bullets prominent C7 transverse process abnormal clavicle or first rib login to view 3 more bullets acromioclavicular (AC) or sternoclavicular (SC) joint injury or dislocation osseous tumors login to view 3 more bullets chronic overuse repetitive shoulder use login to view 2 more bullets athletes at risk login to view 3 more bullets vascular repetitive compression over time can result vessel damage login to view 4 more bullets Associated conditions Paget-Schroetter syndrome type of venous thoracic outlet syndrome seen in well-developed young athletes intermittent obstruction of the subclavian vein in the costoclavicular space by login to view 2 more bullets results in upper extremity deep vein thrombosis Anatomy Thoracic outlet comprised of three distinct spaces interscalene triangle proximal space borders login to view 3 more bullets contents login to view 2 more bullets subclavian vein does not pass through interscalene triangle login to view 1 more bullet costoclavicular space middle space separated from the interscalene triangle by the first rib borders login to view 4 more bullets contents login to view 2 more bullets retropectoralis minor space distal space also known as the thoraco-coraco-pectoral space or subcoracoid space borders login to view 3 more bullets contents login to view 2 more bullets Presentation History presentation is very variable ranges from mild pain to sensory changes to severe vascular compromise can be unilateral or bilateral neurogenic pain over the neck, trapezius, chest, shoulder and/or arm login to view 1 more bullet upper extremity weakness, numbness and paresthesias login to view 7 more bullets upper extremity heaviness login to view 1 more bullet symptoms can be activity-related and/or occur at night-time login to view 1 more bullet vascular venous login to view 5 more bullets arterial login to view 5 more bullets Physical examination inspection note specific postures, can increase loading on the brachial plexus login to view 3 more bullets skin login to view 4 more bullets muscle atrophy login to view 3 more bullets palpation over the supraclavicular area login to view 1 more bullet skin temperature provocative tests high rate of false positives supraclavicular pressure test login to view 6 more bullets Adson test login to view 9 more bullets costoclavicular manuever login to view 9 more bullets Wright test login to view 10 more bullets Roos test / elevated arm stress test login to view 9 more bullets Cyriax release test login to view 6 more bullets Evaluation Radiographs recommended views chest radiograph and cervical spine radiographs findings cervical rib prominent C7 transverse process low lying shoulder girdle Pancoast tumor CT indications identify osseous space-occupying lesions evaluate malunited fractures of the ribs or clavicle MRI indications evaluate for soft tissue anatomic anomalies Nerve conduction studies EMG and NCV historically thought to be equivocal and unhelpful studies were often normal unless significant permanent nerve damage was already established recently discovered that nerve fibers from C8 and T1 may show early changes in neurogenic TOS abnormal nerve conduction velocities in the medial antebrachial cutaneous nerve and median motor nerve to the abductor pollicis brevis Vascular studies doppler ultrasound helpful for evaluating subclavian vein for obstruction or thrombosis login to view 1 more bullet angiography CT or MR angiography arteriography login to view 1 more bullet venography login to view 1 more bullet Treatment Nonoperative activity modification, pain control, physical therapy and modalities indications login to view 1 more bullet technique login to view 9 more bullets outcomes login to view 4 more bullets anterior scalene blocks indications login to view 1 more bullet technique login to view 1 more bullet outcomes login to view 1 more bullet Operative thoracic outlet decompression indications login to view 2 more bullets technique login to view 17 more bullets vascular intervention indications login to view 4 more bullets technique indications login to view 11 more bullets Technique Thoracic Outlet Decompression approaches transaxillary login to view 9 more bullets supraclavicular login to view 7 more bullets posterior login to view 6 more bullets decompression techniques first rib resection, anterior and middle scalenectomy, neurolysis login to view 5 more bullets Complications Pneumothorax is one of the most common complications of first rib resection