Thoracic outlet syndrome (TOS) is a condition that arises from the compression of one or more of the neurovascular structures that traverse the superior aperture of the chest. The name was previously designated according to the etiology of the compression, that is, scalenus anticus, costoclavicular, hyperabduction, cervical rib, or first rib syndrome. Most compressive factors operate against the first rib and produce a variety of symptoms, depending on which neurovascular structures are compressed. These factors, along with common etiologies and symptoms, are illustrated in Figure 143-1. My introduction (H.U.) to TOS came in 1947 at Princeton University, where, as a member of the undefeated freshman football team, my neck was knocked severely to the right, paralyzing my arm for several days. After the season, I was sent by train to Johns Hopkins Hospital to be evaluated by Dr. George Bennett, the eminent orthopedic surgeon who had recently operated on Joe DiMaggio’s knee. He made the diagnosis of a cervical rib syndrome on the right and offered me an operation or a brace. Recognizing early that surgery was for others, I tried the brace. A piece of stainless steel covered only with leather was fashioned on my shoulder pad. It extended up past my right ear to prevent my neck from being driven to the right. I used this for the next year. However, in those days, no one wore a facemask, and I was often chagrined to find a piece of nose or face or teeth on the ground after a substantial block from the single-wing formation. For this reason, the NCAA ultimately outlawed the brace. Subsequently, the foam rubber “doughnut” was developed to prevent the neck from being forced to extremes in any direction. It is commonly used today. Conservative treatment, then as now, is usually effective. With no surgery, I contributed significantly to our undefeated team, which produced “Coach of the Year” Charles W. Caldwell, Jr., and the last Heisman Trophy winner in the Ivy League, Richard W. Kazmaier, Jr.

Since my diagnosis in 1947, many changes in the recognition and management of these multiple conditions have evolved. This chapter elucidates the improvements in the diagnosis and management of thoracic outlet neurovascular compression that have transpired over the past 50 years. Recognizing that such procedures as breast implantation and median sternotomy may produce TOS has been revealing. Prompt thrombolysis followed by surgical venous decompression for the Paget–Schroetter syndrome (i.e., effort thrombosis of the axillary–subclavian vein) has improved results in this condition significantly as compared with the conservative anticoagulation approach. Complete first rib extirpation at the initial operation reduces the incidence of recurrent neurologic symptoms or the need for reoperation. Well over 20,000 patients have been evaluated for TOS in my experience; 4914 underwent neurovascular decompression operations, whereas 1721 had reoperations for recurrent symptoms (primarily from other centers). The evaluation of these patients provides the basis for my recommendation for conservative management and the indications for surgical intervention.

The incidence of any type of compression – arterial, venous, or nerve – presenting to the physician varies with the type of referral practice and specialty the particular physician may have. For example, the orthopedist is prone to see a high number of cervical ribs, the neurologist will see nerve compression patients, and a vascular surgeon will see more aneurysms and arterial/venous occlusions. The thoracic surgeon lies somewhere in between. In addition, the kinds of diagnostic techniques that are available may determine which center a patient is attracted to for management of a particular pathology.

Peet et al. coined the term thoracic outlet syndrome to designate compression of the neurovascular bundle at the thoracic outlet.¹ Until 1927, the cervical rib was commonly thought to be the cause of symptoms of this syndrome.² Galen and Vesalius were the first to describe the presence of a cervical rib. Hunauld, who published an article in 1742, is credited by Keen³ as the first observer to describe the importance of a cervical rib in causing symptoms. In 1818, Cooper medically treated symptoms of a cervical rib with some success. In 1861, Coote⁴ performed the first operation of cervical rib removal. In 1916, Halsted⁵ stimulated interest in dilation of the subclavian artery distal to the cervical ribs. Law⁶ in 1920 reported the role of adventitious ligaments in producing cervical rib syndrome. In 1927, Adson and Coffey⁷ suggested a role for scalenus anticus muscle in producing cervical rib syndrome. This was further developed by Naffziger and Grant⁸ and by Ochsner et al.⁹ in 1935, who popularized resection of the scalenus anticus muscle. In 1943, Falconer and Weddell¹⁰ incriminated the costoclavicular membrane in the production of neurovascular compression. Wright¹¹ in 1945 described the hyperabduction syndrome with compression in the costoclavicular area by the tendon of the pectoralis minor. Rosati and Lord¹² in 1961 added claviculectomy to anterior exploration, scalenectomy, cervical rib resection when present, and resection of the pectoralis minor and subclavius muscle, as well as the costoclavicular membrane.

The role of the first rib in causing symptoms of neurovascular compression was recognized by Bramwell¹³ in 1903. Murphy¹⁴ is credited with the first resection of the first rib. Brickner¹⁵ and Milch¹⁶ in 1925 and later Telford and Stopford¹⁷ suggested that the first rib was the culprit. Clagett¹⁸ in 1962 emphasized the importance of the first rib and popularized the posterior thoracoplasty approach for first rib resection to relieve neurovascular compression. Falconer in 1962¹⁹ emphasized the anterior approach for first rib resection to relieve costoclavicular compression. Roos²⁰ in 1966 introduced the transaxillary route for first rib extirpation, and our modification of his technique is presented in this chapter.

In the late 1950s and early 1960s, the operation of choice in our practice was the supraclavicular scalenotomy. This procedure involved a partial scalenectomy with neurolysis of the brachial plexus (when indicated) combined with resection of a cervical rib (if present). Early results in 336 patients were extremely good (310 of 336). However, the longer-term follow-up was not as satisfactory. Five-year improvement was present in 150 of 336 patients. However, at 20 years, only 31 of 336 patients were still improved. (We are unable to tell whether this represents 10% or 20% of the total series because 20 patients were lost to follow-up.) For this, and other reasons set forth in the presentation by Dr. O. T. Clagett in 1962,¹⁸ the posterior approach for resection of the first rib, the so-called common denominator for thoracic outlet compression forces, was adopted. Subsequently, the initial operation usually was performed through the transaxillary approach because no muscle division was required, and morbidity for the patient was reduced. The supraclavicular or infraclavicular approach, or a “combined approach,” was used for arterial lesions. The posterior approach is now reserved for reoperation in patients with recurrent TOS for removal of rib remnants, regenerated fibrocartilage with neurolysis of C7, C8, and T1 nerve roots, and brachial plexus.

Nerve Compression

The most common symptoms of nerve compression are pain and paresthesias. About 95% of patients exhibit these symptoms; fewer than 10% exhibit motor weakness. Pain and paresthesias are segmental in 75% of cases, and 90% involve the ulnar nerve distribution.²¹ TOS can occur in older patients (oldest age 87 years). When nerve compression symptoms occur in patients older than age 60, other causes should be suspected, most frequently degenerative or traumatic cervical spine pathology or cardiac or pulmonary etiologies.

There may be multiple points of compression of the peripheral nerves between the cervical spine and hand in addition to the thoracic outlet. In the instance of multiple compression sites, less pressure is required at each site to produce symptoms. Thus a patient may have concomitant TOS, ulnar nerve compression at the elbow, and carpal tunnel syndrome. This phenomenon has been designated the multiple crush syndrome.²²

Pseudoangina

The pain experienced by individuals with TOS is frequently insidious in onset and commonly involves the neck, shoulder, arm, and hand. Some patients experience atypical pain, involving the anterior chest wall and parascapular area. This symptom is termed pseudoangina because it simulates angina pectoris.

A group of patients with chest pain simulating angina pectoris but with normal coronary angiograms was evaluated in 1973. When either medical or surgical therapy for TOS relieved the symptoms of pseudoangina (in 330 patients), the diagnosis was deemed to have been confirmed.²³

It is important to remember that there are at least two types of pain pathways in the arm—the commonly acknowledged (C5-T1) somatic, “more superficial” pain, and the afferent sympathetic nerve fibers that transmit “deeper” painful stimuli from the heart, esophagus, chest wall, and arm.

The cell bodies of the two types of afferent neurons are situated in the dorsal root ganglia of the corresponding spinal segments. They synapse in the dorsal gray matter of the spinal cord, and the axons of the second-order neurons ascend in the spinal cord up to the brain. Compression of the “superficial” C8-T1 cutaneous afferent fibers elicits stimuli that are transmitted to the brain and recognized as integumentary pain or paresthesias in the ulnar nerve distribution. In contrast, compression of the predominantly “deeper” sensory fibers elicits impulses that are appreciated by the brain as deep pain originating in the arm or the chest wall, even if the source of the impulses is cardiac (referred pain).

The pseudoangina experienced in thoracic outlet compression shares with angina pectoris the same dermatomal distribution. The heart, arm, and chest wall have afferent fibers converging on T2-T5 spinal cord segments, and their cell bodies are located in the corresponding dorsal root ganglia. Referred pain to the chest wall is a component of both pseudoangina and angina pectoris. Because somatic pain is more common than visceral pain, the brain has “learned” from past experience that activity arising in a given pathway is caused by a pain stimulus in a particular somatic area.

A careful history and physical examination are essential for diagnosis. There are four basic maneuvers used to elicit the classical physical signs of thoracic outlet compression.^23,24 These include the Adson test, the costoclavicular test, the Roos test, and the Wright test. The Adson (or scalene) test contracts the anterior and middle scalene muscles, resulting in a decrease in the interscalene triangle and intensifying any preexisting compression of the subclavian artery and brachial plexus. To perform the maneuver, the patient is asked to take and hold a deep breath while extending the neck fully and turning the head toward the involved extremity (Fig. 143-2A). This action should result in a decrease in the radial pulse. The costoclavicular test (military position) narrows the costoclavicular space by narrowing the area between the clavicle and first rib. The maneuver is performed by having the patient hold his shoulders down and backward (Fig. 143-2B). Loss of radial pulse and reproduction of symptoms indicate compression of the neurovascular bundle. The Roos test is performed over 3 minutes by holding both arms at 90 degrees of abduction and external rotation with the shoulders drawn back (Fig. 143-2C). The patient is instructed to open and close the hands slowly for 3 minutes. Numbness or pain will occur in the hands and forearms. The hyperabduction (or Wright) test is performed with the arms hyperabducted to 180 degrees and externally rotated (Fig. 143-2D). Compression is suspected if there is a decrease in radial pulse. As with most clinical tests, these maneuvers are not specific for thoracic outlet syndrome, and 56% of normal patients may have at least one positive test.²³

The objective test for thoracic outlet peripheral nerve compression in our clinic is the nerve conduction velocity (NCV) test.^25,26 Reduction in NCV below 85 m/s of either the ulnar or median nerves across the thoracic outlet corroborates the clinical diagnosis. More than 8000 NCV studies have been performed annually at Baylor University Medical Center for many years. Approximately 2000 patients per year demonstrate TOS.^27,28

The electromyogram should be normal and rules out other neuromuscular disorders. With conduction velocities above 60 m/s, the patient is usually improved with appropriate conservative physical therapy.

The principles of conservative management have been outlined by Novak and MacKinnon, as well as by Caldwell and Crane^26,29 Initially, most patients are treated conservatively with physical therapy, except those with vascular problems. The primary goals of physical therapy, for predominately “neurological” patients, are to “open up” the space between the clavicle and first rib, improve posture, strengthen the shoulder girdle, and loosen the neck muscles. This is accomplished by pectoralis stretching, strengthening the muscles between shoulder blades, assumption of good posture, and active neck exercises, including chin tuck, flexion, rotation, lateral bending, and circumduction. It is imperative to rule out other causes of TOS-like symptoms, such as cardiac or pulmonary disease.

Failure of appropriate conservative therapy together with significantly reduced NCVs below 60 m/s (normal 85 m/s) and the elimination of other possible etiologies for the patient’s symptoms are the usual indications for surgery of neurological thoracic outlet syndrome.

Initial therapy involves complete first rib resection, anterior scalenectomy, resection of the costoclavicular ligament, and neurolysis of C7, C8, and T1 nerve roots and the brachial plexus through a transaxillary approach (described below).³⁰ The first rib with the compressive elements also may be removed through the supraclavicular approach.³¹ The supraclavicular approach has the disadvantage of working through and retracting the brachial plexus as well as producing a visible scar in women (the preponderant gender with TOS). The posterior thoracoplasty approach for first rib resection may be used for initial therapy, but it is better reserved for reoperation and neurolysis of the brachial plexus (not described).^32,33 Cervical ribs may be removed through any of the approaches described. Dorsal sympathectomy also may be performed with neurovascular decompression through any of the preceding incisions for sympathetic maintained pain syndrome (SMPS), reflex sympathetic dystrophy, causalgia, and Raynaud phenomenon and disease.³³

The initial surgical therapy involves a complete first rib resection, anterior scalenectomy, resection of the costoclavicular ligament, and neurolysis of the C7, C8, and T1 nerve roots and the brachial plexus through a transaxillary approach. The transaxillary, transthoracic approach is performed through the second interspace with a transverse subhairline incision (Fig. 143-3).

The first rib is exposed, revealing the scalene muscles and vessels (Fig. 143-4). The anterior scalene is divided, the periosteum is opened, and a triangular-shaped segment of the first rib is excised (Fig. 143-5). The anterior portion of the rib is resected at the cartilage and removed, after which the middle scalene muscle is divided (Fig. 143-6). Next, the posterior section of the rib is resected (Fig. 143-7) with full attention to the T1 and C8 nerve roots to avoid injury. The head and neck of the rib are removed with rongeurs, and the dorsal sympathetic chain is identified and divided through the lower stellate ganglion above the T1 and below the T3 ganglia (Fig. 143-8).