The Recognition Of Anatomy And The Advance Of Treatment On Thoracic Outlet Syndrome

The term "Thoracic outlet syndrome" (TOS) is used to describe patients with compression of brachial plexus, subclavia artery and subclavia vine in the region of the thoracic outlet. The main symptoms were discomfort at cervical and shoulder areas, tingling of extremity, muscle atrophy, numbness, pain distributing along the medial side of forearm and ulnae side of the hands, and patients not knowing where to pose their upper extremity.The compression of brachial plexus is common and the compression of vessel is seldom in thoracic outlet syndrome. They can appear lonely or together. The compression of the lower trunk of brachial plexus that cross the first rib is the most. So 75% patients appear this symptom. We call this type of TOS is typical case. Upper trunk type of thoracic outlet syndrome is thought to be very seldom for a long time before. In fact, the disease is very common. The most reason why we think so is it belongs to cervical spondylopathy. Today, scalene anterior and middle muscles are thought to be the important anatomy of thoracic outlet syndrome. The recent reports show the origin parts of anterior and middle scalene muscle have a close relation to upper trunk type of thoracic outlet syndrome.In 1860, Wilshire suggested that the cervical rib was the cause of the compression of the brachial plexus; In 1947 Adson offered the one of the factors of the thoracic outlet syndrome was the abnormal neck frame, including elongated transverse process of the seventh cervical, the raised of subclavia artery. In1948,Kirgis suggested that the minimum scalene is the cause of the compression of the lower trunk of the brachial plexus. Later, the research of Wrights Roos Dellon Gu YuDong,et al. made us know the thoracic outlet syndrome more. In 1995, Chen DeSong, et al, investigate the etiology of TOS from the point of scalene and clinical view. Anatomical study was made on both sides of 30 cadavers. The minimum scalene muscle and the insertions of anterior and middle scalene muscle were disserted and observed. Clinically, 53 cases of thoracic outlet syndrome (TOS) were treated and followed up. The minimum scalene muscle was found in 88.3% of the cadavers. Tl nerve root or the lower trunk of bronchial plexus crossed the first rib just over the proximal tendinous part of minimum scalene muscle. Scalene anterior and middle muscle originated from both anterior and posterior tubercle of C2 to C6 to C7 transverse process respectively. Such bundles of muscle from anterior and posterior tubercle pinched the never roots of C5~6 emerging immediately from intervertebral foramen. The contraction of the origin components of the scalene anterior and middle muscles plays an important role in the production of upper trunk type of thoracic outlet syndrome. The tendinous tissue of minimum muscle is the cause of the compression of Tl nerve root or the lower trunk of the brachial plexus.The basic method of operative treatment for thoracic outlet syndrome was divided into two groups includes removal of first rib and resection of both anterior and middle scalene muscles. The recent report showed partial resection of the origin parts of anterior and middle scalene muscle with minor incision at the neck assisted by endoscope is a new way with minimal trauma for treatment of TOS.