and transcutaneous nerve stimulation devices along with biofeedback, mus¬ cle relaxants, nonsteroidal antiinflammatory drugs, and sleeping medication to try to establish normal sleep patterns to promote emotional and neuromuscular relaxation can be offered for several weeks or months to see if the brachial plexus irritation abates and the symptoms become more tolerable. In early and mild cases, the results may be gratifying, but in more advanced cases, the symptoms and

neurologic compression are usually too severe for these therapeutic modalities to be effective, and only mechanical

anatomic alteration has a chance to offer resolution of the progressively

incapacitating symptoms.

For the most common type of TOS, the lower plexus involvement, removal of the bony floor of the thoracic outlet and the first rib and cervical rib if

present, along with the anomalous fi-

bromuscular bands that are always found in carefully selected patients, will offer gratifying relief in 80% to 90% of patients with severe symp¬ toms.5·6 This is most safely and ade¬

quately accomplished through a transaxillary approach. If the upper plexus is predominantly involved, supraclavicular anterior scalenectomy, as distinguished from the obsolete scalenotomy used in the 1930s and 1940s,

offering

the

Although complications of such

op¬

has the best chance of most relief available.2·7

erations

can

be severe, in the form of

life-threatening hemorrhage, perma¬ nent neurologic deficit of the arm and hand from brachial plexus injury, and winged scapula from long thoracic nerve trauma, such complications are rare.2 In many cases, the most gratify¬ ing results are the remarkable relief of

severe

headaches,

return to normal

sleep patterns, and relief of the sec¬ ondary emotional reactions of frustra¬ tion, anger, and irritability. Dealing with patients who have TOS requires thorough knowledge of the various symptom complexes and great patience with people suffering severe, often incapacitating and frightening symptoms that they or their previous physicians do not understand. How¬ ever, if an accurate diagnosis is made, if surgical candidates are chosen with care, and if the appropriate operations are performed with meticulous tech¬ nique, significant, if not total, relief is the happy outcome in the majority of patients, even after all attempts at

conservative treatment have failed. These often neglected patients may become some of the most gratified and appreciative people we see in our neu¬ rologic and surgical practices.

References 1. Roos DB. Congenital anomalies associated with thoracic outlet syndrome: anatomy, symptoms, diagnosis and treatment. Am J Surg.

1976;132:771-778.

2. Roos DB. The place for scalenectomy and first rib resection in thoracic outlet syndrome.

Surgery. 1982;92:1077-1085.

3. Daub JR. Nerve conduction studies in the

The Thoracic Outlet Asa J.

promise of the neurovascular

struc-

tures\p=m-\subclavian/axillaryartery and

vein, distal cervical roots, brachial plexus fibers\p=m-\traversingthe thoracic outlet.1 Thoracic outlet syndrome can be subdivided into four distinct sub-

groups, depending on the particular structure affected, because seldom is

than

one

involved simultane-

ously.2 These subgroups are arterial vascular, venous vascular, true (or classic) neurologic, and disputed neurologic.3 The first three types are

noncontroversial. Because of space limitations the vascular types cannot be discussed in detail; detailed descriptions of them are available.3-6 They share several common features with Accepted for publication April 13, 1989. From the Electromyography Laboratory, Neurology Department, Cleveland (Ohio) Clinic Foun-

dation.

Reprint requests to Electromyography Laboratory, Neurology Department, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195

outlet syndrome. Am J Surg. 1979;138:175-181. 7. Qvarfordt PG, Ehrenfeld WK, Stoney RJ. Supraclavicular radical scalenectomy and transaxillary first rib resection for the thoracic outlet syndrome: a combined approach. Am J Surg.

1984;148:111-116.

1971;173:429-433. 6. Etheredge S, Wilbur B, Stoney RJ. Thoracic

Syndrome Is Overdiagnosed

Wilbourn, MD

Thoracic outlet syndrome (TOS) refers to disorders attributed to com-

more

thoracic outlet syndrome. Neurology. 1975;25:347. 4. Raskin NH, Howard MW, Ehrenfeld WK. Headache as the leading symptom of the thoracic outlet syndrome. Headache. 1985;25:208-210. 5. Roos DB. Experience with first rib resection for thoracic outlet syndrome. Ann Surg.

(Dr Wilbourn).

the true neurologic type (true N-TOS), including characteristic symptom profile, obvious clinical findings, confirmatory results of laboratory studies, worldwide recognition as an entity, and low incidence. For example, true N-TOS is a rare lesion that occurs unilaterally and primarily affects adult women. Caused by the distal C-8/T-1 roots or proximal lower trunk of brachial plexus fibers being stretched over a taut congenital band extending from the first rib to a rudimentary cervical rib, it presents with a long history of sensory symptoms along mainly the medial forearm, associated with hand weakness and wasting, particularly of the lateral thenar muscles. Helpful laboratory studies include roentgenograms that reveal the bony abnormal¬ ity (but not the cervical band) and electromyographic examination that shows a chronic, severe, axon loss lower trunk brachial plexopathy. Sec¬ tioning the band relieves sensory symptoms and stops progression of the motor abnormalities.3,7,8 In contrast, the remaining sub-

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disputed neurologic TOS (dis¬ puted N-TOS), possesses none of the above characteristics. Instead, it has many unique features, unparalleled in the field of peripheral neurology. First, although reputedly a neuro¬ logic disorder, disputed N-TOS rarely is mentioned in the neurologic litera¬ ture; it owes its origin and most of its popularity to non-neurologically trained physicians, particularly tho¬ racic surgeons. It is predominantly a group,

revival of the scalenus anticus syn¬

drome, often diagnosed in the 1940s and 1950s, and attributed to compres¬ sion of the brachial plexus, particu¬ larly the lower trunk, by an abnormal

scalenus anticus muscle. Scalenus an¬ ticus syndrome lost its credibility after carpal tunnel syndrome and cervical radiculopathy were recognized, and its high surgical failure rate (60%) be¬ came known.23 Disputed N-TOS origi¬ nated in 1962, when Clagett9 proposed first thoracic rib removal to treat all the entities then considered subtypes of TOS, convinced that the rib was the "common denominator" in their symp-

production. Equally important, he directed the attention of thoracic sur¬ geons to the thoracic outlet region.9 In 1966, a new surgical approach for first rib resection, the transaxillary, was introduced. Because of its cos¬ metic appeal, relative simplicity, and alleged safety, it generated an enor¬ mous increase in interest in this entity and particularly in its surgical treatment.10 The importance of this operation to the development of dis¬ puted N-TOS cannot be overempha¬ sized.3 In 1976, a new subset of disputed torn

N-TOS, the "upper plexus" type,11 ap¬ peared, for which a new surgical pro¬ cedure was devised, total anterior scalenectomy.12 By 1986, the latter ac¬

counted for 15% of the 1920 TOS oper¬ ations performed by a single thoracic surgeon, the remaining 85% being first rib resections to treat the older "lower plexus" subset.13 Another unique feature is the reluc¬ tance of many of its proponents to clearly distinguish it from the other, noncontroversial TOS subgroups. In¬ stead of considering it in isolation, they often discuss TÓS as a rather ho¬ mogeneous entity, with the presenta¬ tion of all types intermingled, making recognition of this controversial sub¬ group difficult (eg, see article by Urschel et al14). Moreover, many consider it an early evolutionary stage of true N-TOS, which it definitely is not.3 For of identification, it has been des¬ ignated disputed N-TOS, a term that emphasizes its most outstanding property.31516 A third unique feature is the strik¬ ing lack of consensus among its advo¬ cates regarding so many of its funda¬ mental aspects. Although not appar¬ ent from reading single articles on the subject, they agree on surprisingly lit¬ tle about this entity except that it is a common disorder, especially in ease

women.

Debated

are

such basic fea¬

tures as its underlying pathologic find¬

ings, the structure(s) affected (nerve fibers alone? nerve fibers plus blood vessels?), its characteristic clinical

presentation, helpful adjunctive tests, optimal methods of treatment, and, if the latter are surgical, what proce¬ dure^) to use. No other alleged neuro¬ logic disorder has so many of its fun¬ damental concepts in dispute, with so many of the disputes being between its proponents.315 SYMPTOMS

The symptoms that have been at¬ tributed to this entity are astounding in their variety and number. Men¬ tioned most often are pain and pares¬ thesias in a lower trunk ("ulnar

nerve") distribution,12 a symptom com¬ plex essentially appropriated from the

discredited scalenus anticus syn¬ drome. However, its symptom reper¬ toire has been expanded, by one pro¬ ponent or another, so that it is now all-inclusive. "The vagueness and gen¬ erality of the reported symptoms are truly striking_"17 In addition, many of its symptoms—migraine headaches,

loss, ear pain, conjunctival hyperemia, etc—lack a known neumemory

roanatomic basis.1820

SIGNS

Disputed N-TOS is usually described as a disorder that produces many symptoms but few, if any, objective changes.21 Some advocates consis¬ tently report finding "subtle" weak¬ ness and/or sensory loss.12 However, the ability of non-neurologically trained physicians to readily detect minimal neurologic abnormalities that elude detailed examinations by neurologists has been questioned.21 Difficulties thus are encountered when one attempts to diagnose this entity on the basis of its clinical pre¬ sentation, as recommended by its proponents,12·22 because its symptoms "defy categorization"17 and its objec¬ tive clinical findings are either nonex¬ istent or suspect. ANCILLARY TESTS

In practice, diagnosis occurs when a physician proclaims that the clinical profile, whatever that may be, is "typ¬

ical" for TOS and some "confirmato¬ ry" test result is positive. The latter may be a physical or a laboratory ex¬ amination procedure.3 More than 20 different ones have been described as being the optimal adjunctive study.3·15 There is no consensus regarding the relative value of these; a procedure considered indispensable by one pro¬ ponent is frequently rejected as worth¬ less by another.3 Several of these an¬

cillary procedures are electrophysio¬ logic in nature. Over the years more

than a half dozen of them have been heralded as being both highly sensitive and specific for this type of TOS. At

present, somatosensory-evoked poten¬ tials apparently hold center stage, a

position formerly occupied by the nee¬ dle electrode examination, various ul¬ motor conduction studies, F waves, F loops, and needle stimulation of the C-8 root.3·15·22 nar

THERAPY

The most appropriate therapy for this entity is in dispute, not only re¬ garding conservative vs surgical man¬ agement but, if the latter is elected,

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which procedure(s) to employ.22 Transaxillary first rib resection was the mainstay for years but, presumably because of the failure rate associated with it, combining rib resections with scalenectomies is becoming fash¬ ionable.12·23 Fortunately, almost all of the therapeutic regimens reported, conservative or surgical, reputedly prove successful in approximately 80% to 90% of patients,17·22 causing one "to wonder what would have happened with no therapy at all."17 A fourth unique feature is its inci¬ dence, which varies enormously from one physician, hospital, city, and coun¬ try to another, depending on its per¬ ceived credibility.3·15 At the extremes are skeptics who deny its existence,24 and countries where it is essentially unknown,25 to proponents who believe it makes up 99% of all TOS11 and can be "recognized in about 8% of the population"26 (20 million persons in the United States alone!). Disputed N-TOS has provoked grow¬

ing

concern

among many

physicians

for several reasons. First, unques¬ tioned neurologic disorders are being mislabeled as TOS, especially when the diagnosing physicians are untrained in neurologic differential diagnoses and when modern neurologic diagnos¬ tic techniques are not used. An exam¬ ple is carpal tunnel syndrome. Some physicians unjustifiably exclude it from consideration when (1) paresthe¬ sias affect the entire hand, (2) some physical examination findings (eg, lat¬ eral thenar wasting) are absent, and (3) the elevated arm stress test of Roos27 (EAST procedure) is positive. However, (1) almost all of the patients do complain of the entire hand being "numb," although any sensory loss present is limited to the median nerve distribution; (2) thenar wasting is a late finding, seen in progressively fewer patients today, thanks partly to sensitive electrodiagnostic studies; and (3) the EAST procedure is positive in 92% of patients with carpal tunnel syndrome.28 Conversely, the propo¬ nents of disputed N-TOS often refuse to use electrodiagnostic studies, which almost all neurologists consider the premier means of diagnosing this neu¬ rologic abnormality, dismissing them as "too expensive" and "confusing."27 All too often the result is unnecessary TOS surgery with concomitant delays in reaching the correct diagnosis. Sec¬ ond, TOS surgery is far from being the safe, simple procedure it was once considered. Many patients have sus¬ tained severe, permanent intraopera¬ tive injuries, particularly lower trunk brachial plexopathies.16·29 In our elee-

we have about the same number of pa¬ tients with postoperative brachial plexopathies as patients with true N-TOS (18 patients). Third, disputed N-TOS has become a potent force in personal injury lawsuits and worker's compensation cases, as trauma, often both remote and trivial, has been named with ever-increasing frequency as its inciting cause.331 Such an ill-de-

tromyography laboratory seen

fined entity is a plaintiff lawyer's dream and one likely to seriously dis¬ tort the judicial process. CONCLUSION

Thoracic outlet syndrome is highly A great variety of symptoms are being attributed to some hypothetical brachial plexus le¬ sion, confirmation of which has proved remarkably elusive over the years,

overdiagnosed.

since it

causes no undisputed clinical electrophysiologic abnormalities. Perhaps now is the time for physicians

or

to look to other than the thoracic out¬ let for the cause of most of these symptoms and to concede that the

"ore" (ie, TOS) Clagett9 reported find¬ ing in the "great Thoracic mine" in

1962, which initiated the present dis¬

puted N-TOS goldrush, contains little gold and much pyrite.

very

References 1. Peet RM, Henriksen JD, Anderson TP, Martin GM. Thoracic outlet syndrome: evaluation of a therapeutic exercise program. Mayo Clin Proc.

1956;31:281-287.

2. Gilliatt RW. Thoracic outlet syndromes. In: Dyck PJ, Thomas PK, Lambert EH, Bunge TR, eds. Peripheral Neurology. 2nd ed. Philadelphia, Pa: WB Saunders Co; 1984;2:1409-1424. 3. Wilbourn AJ, Porter JM. Thoracic outlet syndromes. In: Weiner MA, ed. Spine: State of the Art Reviews. Philadelphia, Pa: Hanley and Belfus; 1988;2:597-626. 4. Rob CG, Standeven A. Arterial occlusion complicating thoracic outlet compression syndrome. Br Med J. 1958;2:709-712. 5. Pairolero PC, Walls JT, Payne WS, Hollier LH, Fairbairn JF. Subclavian-axillary artery aneurysms. Surgery. 1981;90:757-763. 6. Hughes ESR. Venous obstruction in the upper extremity (Paget-Schrotter's syndrome): a review of 320 cases. Surg Gynecol Obstet. 1949;88:89-127. 7. Gilliatt RW, Le Quesne PM, Logue V, Sumner AJ. Wasting of the hand associated with a cervical rib or band. J Neurol Neurosurg Psychiatry. 1970;33:615-624. 8. Hardy RW, Wilbourn A, Hanson M. Surgical treatment of compressive cervical band. Neurosurgery. 1980;7:10-13. 9. Clagett OT. Presidential address: research and prosearch. J Thorac Cardiovasc Surg. 1962;44:153-166. 10. Roos DB. Transaxillary approach for first rib resection to relieve thoracic outlet syndrome. Ann Surg. 1966;163:354-358.

11. Roos DB. Congenital anomalies associated with thoracic outlet syndrome. Am J Surg.

1976;132:771-778.

12. Roos DB. The place for scalenectomy and first-rib resection in thoracic outlet syndrome.

Surgery. 1982;92:1077-1085.

13. Roos DB. Thoracic outlet syndromes: symptoms, diagnosis, anatomy and surgical treatment. Med Probl Perfor Art. 1986;1:90-93. 14. Urschel CH, Razzuk MA, Wood RE, Parekh M, Paulson DL. Objective diagnosis (ulnar nerve conduction velocity) and current therapy of the thoracic outlet syndrome. Ann Thorac Surg. 1971;12:608-620.

15. Wilbourn AJ. Thoracic outlet syndrome. In: Syllabus, Course D: Controversies in Entrapment Neuropathies. Rochester, Minn: American Association of Electromyography and Electrodiagnosis; 1984:28-38. 16. Wilbourn AJ. Thoracic outlet syndrome surgery causing severe brachial plexopathy. Mus-

cle Nerve. 1988;11:66-74. 17. Porter JM, Rivers SP, Coull BM, Baur GM. Thoracic outlet syndrome: a conservative approach. Vase Diagn Ther. 1982;3:35-42. 18. Fernandez Nola EL, Lopez S. Thoracic outlet syndrome: diagnosis and management with a new surgical technique. Herz. 1984;9:52-56. 19. Raskin NH, Howard MN, Ehrenfeld WK. Headache as a leading symptom of the thoracic outlet syndrome. Headache. 1985;25:208-210. 20. Woods WW. Thoracic outlet syndrome. West J Med. 1978;128:9-12. 21. Lederman RJ. Thoracic outlet syndromes: review of the controversies and a report of 17 in-

The Thoracic Outlet

Syndrome

We

particularly if dealing with pain, a modality highly responsive to dra-

tend to find what we look for. Roos encountered "significant soft-tissue anomalies in the thoracic outlet and scalene triangle not illustrated in anatomy textbooks in 33% of cadaver dissections." And yet, it is difficult to know how many of the subj ects had symptoms and signs in life. Similarly, even if anatomic variants are found at operation and symptomatic relief is achieved after it, a firm causal relationship cannot be established,

matic intervention. As Wilbourn points out, the term "thoracic outlet syndrome" is applied to a wide range of entities, from the indisputable to the incredible. Unless the syndrome is cleaved into objectively defined subcategories and subjected to unbiased therapeutic evaluations, the debate about its frequency will never cease.

Downloaded From: http://archneur.jamanetwork.com/ by a University of Iowa User on 06/10/2015

strumental musicians. Med Probl

1987;2:87-91.

Perfor

Art.

22. Dale A. Thoracic outlet compression syndrome: critique in 1982. Arch Surg. 1982;117:1437\x=req-\ 1445. 23. Qvarfordt PG, Ehrenfeld WK, Stoney RJ. Supraclavicular radical scalenectomy and transaxillary first-rib resection for the thoracic outlet syndrome: a combined approach. Am J Surg.

1984;148:111-116. 24. Cherington M. Surgery for thoracic outlet syndrome. N Engl J Med. 1986;314:322.

25. Mellick SA. In discussion: Dale A. Thoracic outlet compression syndrome: critique in 1982. Arch Surg. 1982;117:1437-1445. 26. Urschel HC, Razzuk MA. Thoracic outlet syndrome. In: Sabiston DC, Spencer FC, eds. Gibbons's Surgery of the Chest. Philadelphia, Pa: WB Saunders Co; 1983:437-452. 27. Roos DB. Recurrent thoracic outlet syndrome after first-rib resection. Acta Chir Belg.

1980;79:363-372.

Costigan DA, Wilbourn AJ. The elevated specificity in the diagnosis of the thoracic outlet syndrome. Neurology. 1985; 35(suppl 1):74-75. 29. Cherington M, Happer I, Mechanic B, Parry L. Surgery for thoracic outlet syndrome may be 28.

arm

stress test:

hazardous

to

your

health. Muscle Nerve.

1986;9:632-634.

RJ, Monsour JW, Gerber WF, AdWR, Thompson N. Scalenectomy versus first\x=req-\ rib resection for the thoracic outlet syndrome. Surgery. 1979;85:109-121. 30. Sanders

ams

Given Roos' pioneering work in this field, his reputation, and the nature of his practice, the thoracic outlet syn-

drome may well be underrated in the patients referred to him. However, outside of such a selective experience, and if one insists on the rigorous cri¬ teria demanded by Wilbourn, the tho¬ racic outlet syndrome is almost cer¬

tainly overdiagnosed. Vladimir Hachinski, MD, DSc (Med)