Thoracic outlet syndrome

Abstract

Thoracic outlet syndrome (TOS) is a syndrome that occurs as a result of compression of at least one of the following: subclavian artery, subclavian vein, or brachial plexus. Symptoms vary depending on the compression of nerves and blood vessels. Neurogenic TOS (NTOS) accounts for 90-95% of clinical cases and is caused by compression or irritation of the brachial plexus. The remaining cases are referred to as venous TOS (VTOS) and occur due to narrowing of the subclavian vein. Arterial TOS (ATOS) is the least common type and has been reported in 1-6% of case series. There are many etiological factors involved in the development of TOS. The surgical procedure related to TOS was performed in 1861 in London by Holmes through resection of the first rib. After radiological advancements in 1912, TOS was reported in a patient without cervical ribs. Technically, due to the difficulties in resecting the first rib, scalenectomy was defined by Adson and Coffey. Scalene muscle resection gained popularity due to its technical simplicity, but a posterior approach to the first rib was defined by Clagett in 1962. Alternatively, a transaxillary approach was demonstrated by David Roos. Recently, a surgical approach using VATS was defined. Understanding the complex anatomy is necessary for the management of TOS patients. Areas where pressure can potentially be seen include the interscalene triangle, costoclavicular space, and subcoracoid region, from medial to lateral. Pressure occurs as the brachial plexus and subclavian artery exit the thorax through the first rib and travel between muscles. The compression of neurovascular structures can be explained embryologically by the origin of the scalene muscle mass from C3-C7 vertebrae and its attachment to the first and second ribs. Compression of neurovascular structures can also be accompanied by fibrous bands between these structures. Another important structure for TOS surgery is the phrenic nerve. It has a similar course on the right and left sides and is located in front of the anterior scalene muscle. It is located in front of the subclavian artery and enters the superior mediastinum where the muscle attaches to the first rib. The subcoracoid region is located beneath the pectoralis minor muscle and the brachial plexus passes through this region and extends to the arm. Neurogenic TOS occurs as a result of compression of the brachial plexus. This is the most common subtype of TOS and is seen in approximately 90% of TOS patients. Pain, which varies depending on the severity and duration of pressure on the nerve, is the initial complaint. The most common areas affected are the back of the neck, upper tra- pezius region, clavicle surface, medial scapula, and axilla. Numbness, tingling, and weakness in the affected arm and the 4th and 5th fingers of the hand are also common symptoms. Complaints in the upper extremity increase especially after repetitive motor movements and abduction movements of the arm. Some patients may experience changes in temperature and color. When evaluating patients, all structures including the shoulder, chest wall, and spine should be considered in the differential diagnosis. Thoracic outlet syndrome (TOS); It is a syndrome that occurs after compression of at least one of the following: subclavian artery, subclavian vein or brachial plexus. Symptoms differ in nerve and vascular compression. Neurogenic TOS (NTOS) accounts for between 90-95% of clinical cases and is caused by compression or irritation of the brachial plexus. The remainder of cases is venous TOS (VTOS), which results from stenosis of the subclavian vein. Arterial TOS (ATOS) is the least common type and has been shown to be 1-6% in case series [1-3]. There are many etiological factors in the development of TOS (Table 1).