The Thoracic Outlet Syndrome – Part Two

The physiotherapist will typically begin the examination even before the patient takes off any of their clothes by observing the usual posture they tend to adopt. Posture of the shoulders may be slumped and rounded, forcing a stretch from the neck and shoulder blade muscles which might add to the possibility of this syndrome occurring. The physiotherapist will examine the neck’s ability to reach full range of motion and may increase the testing stresses by compressing the neck whilst it is in a combination of movements. This can bring on the symptoms if normal testing does not.

The examination will include the ability of the nervous and vascular system to supply the requirements of the arm, with most of the deficiencies involving the lower nerves of the brachial plexus. Compression of the veins in the armpit area results in an arm which is bluish in colour and swollen, whilst if the part of the vascular system which is compressed is an artery this makes the arm cooler, lacking in a pulse and often having a lower blood pressure of 20 mmHg or more compared to the normal arm.

In the case of thoracic outlet syndrome due to neurological compression the finding are often of weakness and wasting of the small muscles of the hand. There may also be reduced sensation in the areas supplied by the ulnar nerve, which again reflects the fact that the lower nerves of the brachial plexus are most often involved. The last type of this syndrome, that of non-specific thoracic outlet syndrome, has widespread but less precisely located pain, with less precise and clear examination findings, making the diagnosis unreliable at best.

The large number and type of anatomical structures potentially contributing to thoracic outlet syndrome has meant that there is a large number of tests to provoke the symptoms of the typical syndrome. Unfortunately these tests result in high numbers of results which are false-negative and false positive. False-negative results mean that the tests did not show any evidence for the syndrome but it is present anyhow, and false-positives mean that the test shows the presence of the syndrome when in reality it is not present.

Physiotherapists can perform Roos stress test, whereby the patient is asked to maintain their arms in a position of “hands up” while they close and open their hands repetitively. The test is positive if it brings on the usual symptoms complained of or if the arms feel tired and heavy. The structures which cause thoracic outlet syndrome can be of bony or soft tissue origin. The compression or obstructive problems can be caused by a bony structure such as a neck rib or a bony growth on the clavicle or ribs. Soft tissue compressive forces can be due to a fibrous band or oversize muscles.

The neck may be more likely to develop thoracic outlet syndrome if it suffers some trauma or mechanical stresses which can combine with any anatomical abnormality such as a cervical rib. If the blood vessels are obstructed then this acute syndrome threatens the health of the arm and surgical release of the compression and blood vessel repair should be urgently considered. The remainder of treatment is conservative including TENS (transcutaneous electrical nerve stimulation), anti-inflammatories and physiotherapy assessment and intervention to the neck and shoulder.

Conservative management is useful in a large group of patients and if the pain does not settle over a considerable period then surgery remains an option. Physiotherapy assessment includes any abnormalities of posture and imbalances in muscles around the shoulder and neck region. The maintenance of static postures for considerable times or repeated return to certain postures may provoke abnormal neck function.

Chronic compression may be caused by the postural abnormality increasing the local compression or tension forces on the nerves. If muscles are kept in shortened positions for lengthy periods they may adopt that new length and when stretched, react with pain. Muscle imbalance can occur with some muscles typically lengthened and thereby weakened and others shortened and thereby strengthened. This leads to an abnormal balance of muscular strength and length, generating abnormal forces in the neck region. Education is a significant matter in the treatment of these patients in an effort to change their posture.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Oxford. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.