Question 1

What is the most common cause of neurogenic thoracic outlet syndrome (TOS)?

A.  Neck trauma B.  Cervical rib

C.  Anomalous bands D.  Abnormal first rib E.  All of the above

On physical examination there was supraclavicular tenderness over the right scalene muscles but no tenderness over the left scalenes; tenderness over the right chest wall just below the right clavicle and in the right axilla but no such tenderness on the left side; a positive Tinel’s sign over the right brachial plexus and a negative sign over the left; and reproduction of arm and hand symptoms with pressure over the right scalene muscles, but no such symptoms with pressure over the left scalene muscles. Head rotation and head tilting each caused pain in the contralateral hand and arm when turning and tilting to the left side. This did not occur when rotating and tilting to the right side.

Abducting the arms to 90° in external rotation (AER position) reproduced the right arm and hand symptoms within 15 s while no symptoms developed on the left side. The upper limb tension test (ULTT), modified from Elvey, was positive on the right side in the first position with symptoms worse in the second and third positions. The ULTT was negative on the left side.

Pectoralis minor muscle block, injecting 4 ml of 1% lidocaine into the right pectoralis minor muscle 3 cm below the clavicle, resulted in partial improvement of symptoms at rest, loss of tenderness over the right chest wall and in the right axilla. The ULTT was improved, but she still had some symptoms, partially reduced.

Scalene muscle block, injecting 4 mL of 1% lidocaine into the right anterior scalene muscle, resulted in further significant improvement in most of her physical findings.

Question 2

The diagnostic criteria for neurogenic TOS (NTOS) include which of the following?

A.  History of neck trauma.

B.  Paresthesia in the hand involving all five fingers, more frequently in the fourth and fifth.

C.  Pain in the neck, shoulder, and upper extremity. D.  Occipital headaches.

E.  Scalene muscle tenderness and duplication of symptoms in the 90° AER position. F.  Cut-off of the radial pulse on Adson’s or 90° AER positioning.

G.  Positive response to the scalene muscle block.

H.  The ULTT is comparable to straight leg raising in the lower extremity and is an excellent test for TOS.

Question 3

The diagnostic criteria for neurogenic pectoralis minor syndrome (NPMS) include which of the following?

A.  History of tenderness or pain in the anterior chest wall below the clavicle B.  Tenderness in the right axilla and below the right clavicle

C.  Occipital headaches

D.  Paresthesia in the hand involving the thumb, index and middle fingers E.  Severe weakness in the right arm

She was continuing neck stretching exercises at home on a daily basis emphasizing doing each stretch slowly, holding each stretch for a minimum of 15 s, and performing no more than three repeats at each session. She also was performing pectoralis minor stretches in an open doorway, holding her hand on each door jam as she dropped her body forward. In spite of this treatment, there was no improvement in her symptoms.

Question 4

Which of the following conditions can coexist with NTOS or require differentiation from it?

A.  Carpal tunnel syndrome

B.  Biceps/rotator cuff tendinitis or impingement syndrome

C.  Cervical spine disease-disc, arthritis, spinal stenosis, cervical spine strain,Detc D.  Ulnar nerve entrapment at the elbow (cubital tunnel syndrome)

E.  Pectoralis minor syndrome F.  Fibromyalgia

G.  Brachial plexus injury H.  Brain tumor

Question 5

The indications for surgical decompression of the thoracic outlet areas are:

A.  Failure of conservative treatment after a trial of at least 3 months

B.  All other associated conditions have been recognized and treated as completely as possible

C.  Symptoms are interfering with work, sleep, recreation, or activities of daily living D.  All of the above

Because of persistent symptoms in spite of adequate conservative therapy, and because she waspartiallydisabledatworkandathome,asupraclavicularanteriorandmiddlescalenectomy, brachial plexus neurolysis, and first rib resection were performed along with a pectoralis minor tenotomy via a separate incision in the axilla.

Question 6

Which surgical procedures are acceptable to decompress the thoracic outlet area?

A.  Transaxillary first rib resection

B.  Supraclavicular anterior and middle scalenectomy with brachial plexus neurolysis C.  Supraclavicular anterior scalenectomy with or without brachial plexus neurolysis D.  Supraclavicular anterior and middle scalenectomy, first rib resection, and brachial

plexus neurolysis E.  All of the above

Question 7

What are the major complications of TOS surgery?

A.  Brachial plexus traction injury B.  Phrenic nerve injury

C.  Subclavian artery injury D.  Subclavian vein injury E.  Long thoracic nerve injury

F.  Second intercostal brachial cutaneous nerve injury (transaxillary approach only) G.  Thoracic duct injury (left side, supraclavicular approach only)

H.  Supraclavicular nerve injury (supraclavicular approach only) I.  Horner’s syndrome (supraclavicular approach only)

J.  Pneumothorax K.  All of the above

She tolerated surgery well, had no postoperative complications, and was discharged from the hospital on the second postoperative day. After 4 weeks of convalescence at home, she returned to work, 4 h a day. After 1 month she was able to resume her job on a full-time basis. While most of her symptoms had improved, she still noticed occasional paresthesia in her hand and pain in her right shoulder when working for long periods. Her headaches were completely gone. She was pleased with her improvement from surgery even though she was not back to normal.

Question 8

What are the long-term results of surgical decompression of the thoracic outlet area?

A.  90% success B.  75% success C.  60% success D.  40% success

E.  None of the above

36.1  Commentary

There are three types of thoracic outlet syndrome (TOS): arterial, venous, and neurogenic. NTOS comprises more than 95% of all TOS cases and is the most difficult to diagnose and treat. The etiology of NTOS in most patients is either a hyperextension neck injury or repetitive stress at work. The mechanism of neck injury from repetitive stress is a little obscure, but it probably comes from the worker’s hands being occupied in one place so that the worker is constantly rotating his/her neck back and forth to perform the job or talk to people. Holding a telephone between ear and shoulder while typing is also a common form of neck strain. While some TOS patients have cervical ribs or congenital cervical bands, these are regarded as predisposing conditions and seldom are the primary cause. These patients usually do not develop symptoms until they experience some form of neck

trauma.

Although first rib resection has become a standard form of therapy for neurogenic TOS, the first rib is rarely the cause of the symptoms. The pathology is tightness and scarring of the scalene muscles.1 Rib resection is successful because the anterior and middle scalene muscles must be divided in order to remove the rib. Thus, by necessity, first rib resection includes scalenotomy and it is probably the latter that relieves the symptoms. [Q1: A]

The diagnosis of neurogenic TOS is by history and physical examination. This is not a diagnosis of exclusion. The typical history includes some type of neck trauma, although the patient does not always remember the incident, especially if there was no litigation involved. It is the job of the examiner to thoroughly ask about neck trauma. The symptoms usually include pain, paresthesia, and weakness in the upper extremity, but over 75% of patients also complain of neck pain and occipital headaches. The latter symptoms are not the result of brachial plexus compression; rather, they result from stretch injuries to the scalene muscles and referred pain to the back of the head. Most commonly paresthesia involves all five fingers of the hand, although it tends to involve the ulnar side of the hand and forearm more often than the radial side. The significant physical findings are scalene muscle tenderness, a positive Tinel’s and positive Spurling’s sign over the scalene muscles, and duplication of symptoms with the arms in the 90° AER position. A cut-off of the radial pulse in either the Adson’s or 90° AER position is not a reliable sign in establishing a diagnosis. Up to 60% of normal people cut off their pulses in these dynamic positions while most NTOS patients do not cut off their pulses.2 Not every patient will exhibit all of these criteria, but a diagnosis can be established if the majority of these criteria have been met.3 The upper limb tension test (ULTT) is comparable to straight leg raising in the lower extremity. It is performed by having the patient abduct the arms to 90° with elbows extended, then dorsi-flex the wrists, followed by tilting the head, ear to shoulder, to each side. A positive response is onset of pain and paresthesia in the hand and arm.4 [Q2: A, B,

C, D, E, G, H]

Pectoralis minor syndrome was described over 60 years ago but was forgotten by most clinicians. Its recognition has recently been revived and it appears to be present in the majority of patients being seen for NTOS. It’s symptoms of paresthesia and pain in the upper extremity are similar to those of NTOS. However, neck pain and occipital headaches are not

duetopectoralisminorcompression.Importantsignsonphysicalexaminationaretenderness over the pectoralis minor muscle just below the clavicle and tenderness in the axilla. In contrast from NTOS, patients with NPMS usually don’t have much arm weakness, have very littleneckpain,andmoreoftenhaveparesthesiainthefirstthreefingers,althoughallfivecan be involved. NPMS frequently accompanies NTOS as a form of double crush syndrome.5 Surgery for the two conditions can be performed together.6,7 [Q3: A, B, D]

All symptoms of NTOS are nonspecific. Other conditions that also exhibit similar symptoms include abnormalities of the shoulder, elbow, wrist, and parascapular muscles. It is quite common for NTOS to coexist with some of these other conditions. [Q4: A, B, C,

D, E, F, G]

In less than 1% of patients with NTOS, atrophy of hand muscles supplied by the ulnar nerve exists. In these patients, EMG studies demonstrate typical findings of ulnar neuropathy.8 Otherwise, EMG and NCV studies are either normal or reveal nonspecific changes. Unfortunately, once atrophy develops, it is usually nonreversible.9 At this stage, surgery can relieve pain and paresthesia, but not weakness.

Conservative therapy is always indicated first and is effective in the majority of patients.10 Surgery should be regarded as a last resort. There are a variety of modalities of therapy for NTOS patients, the most important being home exercises, including neck stretching, abdominal breathing, and posture correction. After being instructed by a physical therapist the patient carries out the program on a daily basis at home. Hands-on therapy by a physical therapist is indicated for some of the associated diagnoses that coexist with TOS. Because neck traction, weights, resistance exercises, and strengthening exercises tend to make TOS symptoms worse, we do not recommend them for NTOS patients.

Some patients are refractory to all forms of physical therapy. If there is no improvement after several months of exercises, the patient’s options are to either live with the symptoms or consider surgical decompression of the thoracic outlet. To be a candidate for surgery, in addition to failing conservative therapy after a trial of several months, the patient should have had all associated diagnoses treated and the symptoms should be partially or totally disabling. [Q5: D]

That there is more than one acceptable surgical procedure from which to choose indicates that no one operation has proved itself to be greatly superior to any other.

In 1972, after performing transaxillary first rib resection11 for several years, we were disappointed to find the long-term success rate was just under 70%. We then changed to supraclavicularanteriorandmiddlescalenectomywithbrachialplexusneurolysisbutwere again disappointed to discover the success rate was identical to transaxillary first rib resection. The next choice of procedure was supraclavicular anterior and middle scalenectomy plus first rib resection through the same supraclavicular incision.12,13 With this combined operation our early results were a few percentage points better than the first two operations, but the difference was not statistically significant. Other observers who have compared scalenectomy alone to scalenectomy with first rib resection have also not noted statistically significant differences between the two.14–16 Finally, some surgeons still perform just anterior scalenectomy with neurolysis and report results that are similar to the more extensive procedures.17,18 [Q6: E]

Major complications occur from all operations to decompress the thoracic outlet area regardless of the surgical approach. Injury to the subclavian artery and vein, brachial plexus, phrenic nerve, and long thoracic nerve are the most common serious