DIAGNOSIS OF THORACIC OUTLET SYNDROME
Carlos A. Selmonosky, M.D. FACS, FACCP, FACC, AAFP.
Background; Lack of Accepted Diagnostic Criteria
The actual incidence of the Thoracic Outlet Syndrome (TOS) is unknown, it varies from 1 per million(1) to 100(2) to 3000 to 80,000(3) per million of population, these reports are not supported by valid epidemiological studies. The incidence depends upon the selected diagnostic criteria; the diagnostic criteria can be so restrictive that in some centers the incidence is reported to be 1 in a million(1), while thousands of TOS operations are performed worldwide in many reputable centers.
One of the difficulties in assessing the incidence of TOS in the general population is the lack of a reliable and reproducible set of signs and a common accepted diagnostic criteria or cost-effective laboratory tests(4-5-7-23-65).
TOS is an often misdiagnosed cause of chest(8-9-11-12-51-65), neck and shoulder pain(15-16-60) and it is also one of the frequent upper extremity neurovascular compression syndromes related to sport(17-18-19). TOS may be the most underrated, overlooked, misdiagnosed and most frequent peripheral nerve compression neuropathy(20-21-22-23-24). It is also the most common unrecognized cause of failed carpal or cubital tunnel surgery(25).
Anatomical Basis of TOS
Autopsy studies show a pattern of fibromuscular bands, similar in location to those found in operations for TOS(2-26-28). Clinical studies of selected populations suggest a high prevalence of TOS(29-30-31).
Symptoms; Not Only From the Upper Extremities
Symptoms of TOS are varied, but not all need to be present, therefore the physician should not expect a “typical” presentation of TOS. The symptoms are located not only in the upper extremities, chest pain caused by TOS can mimic anginal pain(8-11-12-51-65). Cardiac sympathetic nerves are the pathway for cardiac pain with ganglionic connections from C8 to T4; the compression of C8-T1 fibers occurring in TOS send impulses to the brain through pathways that are shared by the same dermatomal distribution in coronary ischemia producing chest pain. Positional compression of the vertebral artery also may cause temporary symptoms of vertebrobasilarly insufficiency(32-33-34-35-36-); shoulder and neck pain can be symptoms of TOS(15-16-60). A focused questionnaire and awareness of the numerous symptoms that can be present in TOS would help in clarifying the diagnosis.
PUB MED Search
In spite of more than 2,600 references about TOS quoted in PubMed and thousands of patients operated on yearly worldwide, there is a lack of common accepted diagnostic criteria(4-5-7-23-65). The diagnosis of TOS and the indications for surgery are seldom addressed in the major and most widely read medical journals.
Obstacles to the Diagnosis of TOS
One common obstacle to the understanding of the diagnosis of TOS is the mistaken belief that it is present only when there is atrophy of the hand muscles and positive neurological electrophysiological tests(1-37-38-39). A second obstacle to the understanding of TOS is the artificial division into neural or vascular forms. Many TOS patients have symptoms and signs of both neural and vascular compression(60-65-67-68) if the questioning is focused and the physical examination is pertinent and includes the Diagnostic Triad.
Obstacles Caused by the Misinterpretation of the Vascular Maneuvers
A third obstacle is the confusion surrounding the role of the vascular maneuvers in the diagnosis of TOS. Numerous vascular maneuvers have been described(40-41), all intended to support the diagnosis of TOS if they were positive. Positive means positional changes of the radial pulse amplitude, at one time they were thought to be pathognomonic of TOS(42).
A number of articles have stated that these maneuvers were positive in a large proportion of normal subjects(43-44-45-46-47-48). All of these reports do not define what a “normal” subject is. The documentation regarding the presence or absence of the Triad of Signs in these articles is lacking, or at least the mention of the presence or absence of weakness of the fifth finger. There has not been any long term study of what happens to those normal subjects whom had positive vascular maneuvers.
The real significance of the vascular maneuvers is to detect positional changes of pulse amplitude in the radial artery; the importance of the diagnostic utility of these maneuvers is to determine if they represent an abnormal response to positional changes. Positional compression of the subclavian artery is not a normal phenomenon; therefore a positive vascular maneuver is an abnormality. It is important to give a positive vascular maneuver an explanatory diagnostic or prognostic significance. A positive sign can be associated with absence of symptoms, but the absence of symptoms(49) does not diminish the diagnostic or prognostic significance of a positive test. Comparing vascular maneuvers can also cause confusion(50), all examiners should perform these maneuvers with the patient in the same position, and even a slight change in position may change the results. Therefore a detailed protocol should be used if the results of these vascular maneuvers are being compared in the medical literature.
Conflicting information about the incidence and diagnosis of TOS underscores the necessity for a clear definition and standardized, reliable, consistent set of diagnostic physical signs.
TOS is a group of symptoms arising not only from the upper extremities, but also from the chest, neck, shoulders and head. The symptoms are produced by a positional intermittent or continuous compression of the brachial plexus and/or subclavian artery and/or vein and the vertebral artery.
The diagnosis of TOS should be made by the physician’s awareness of the symptoms and by the use of a Triad of Signs(51-52) during the physical examination.
Selmonosky Diagnostic Triad
The Triad of Signs consists of the following:
Weakness of abduction and adduction of the 5th finger, and weakness of the pinch strength between the thumb and 5th finger as compared with the pinch strength between the thumb and the index finger.
Tiredness and/or paresthesias, numbness of the upper extremity and hand on elevation; associated or not with paleness of the hand.
Tenderness on thumb pressure over the ipsilateral supraclavicular area, lateral to the sternocleidomastoid muscle just above the clavicle. The patient’s nonverbal response, particularly facial grimaces and withdrawal should be observed.
Elevation of the Hand Maneuver
In the elevation of the hands maneuver, the patient sits comfortably elevating the hands above the shoulder girdle with the fingers pointing towards the ceiling and with the palms facing the observer,the thumbs should be close to each other as possible. The axis of the upper extremities should be parallel to the axis of the body. The duration of this maneuver is three minutes or until the patient became symptomatic. This is a test to assess the positional compression of the brachial plexus as manifested by complaints of paresthesias, tiredness and/or numbness of the upper extremity and hand.
The White Hand Sign
It is also important to assess the positional subclavian artery compression at the thoracic outlet by observing the presence of absence of paleness of the hands. The presence of marked paleness is called the White Hand Sign(51-52), and indicates severe positional vascular compression.
The absence of color changes of the hands should not be interpreted as the absence of TOS, since severe nerve compression can be present without severe vascular compression (53-54).
Read more about the White Hand Sign here.
Weakness of the Fifth Finger
Weakness of the fifth finger is a component of the diagnostic triad. It represents the results of the compression of the lower trunk of the branchial plexus, C8 and T1 root fibers by fibromuscular bands or osseous structures. The strength of the fifth finger is never or seldom assessed in the physical examination by Primary Care of Emergency Department Physicians. The simple examination of the pinch strength of the fifth finger as compared to the pinch strength of the second finger can be a clue to the diagnosis of symptoms arising from the upper extremity, chest, neck and shoulder.
Weakness of the fifth finger (pinch strength, abduction, adduction), excluding generalized neuropathies or myopathies, is only found in four compression neuropathies of the upper extremity. The order of frequency as searched in Google, Yahoo and Bing is:
Thoracic Outlet Syndrome
Ulnar Entrapment at the Elbow
Ulnar Entrapment at the Wrist
Isolated C8 or T1 Root Compression
The assessment of the degree of weakness can be done qualitatively: none, mild, moderate, severe; or objectively demonstrated with digital pinch dynamometry.
Physical Examination, Splinting, Posture, Swelling, Sweating and Coldness
The diagnostic triad should be complemented in the physical examination by observation of the posture of the patient, and the presence in the upper extremity of:
Swelling of the Fingers and/or Hands
Coolness or Sweating of the Hands
The sweating of the hands is produced by increased sympathetic tone secondary to mechanical irritation of the sympathetic fibers of the brachial plexus, which may also produce coldness of the hands(12-55-57).
Swelling of the fingers and or hands may occur because of subclavian vein compression at the thoracic outlet being present without thrombosis(58-59-60); the most serious form of venous compression is caused by thrombosis of the subclavian vein and is called: Paget-Schroetter syndrome or effort thrombosis(19-61-62).
Many of the TOS patients have a slouched posture that may reflect depression(62-63-64-65), some with severe pain present with splinting of the upper extremity.
Imaging Needed to Reinforce the Diagnosis
Chest and cervical spine plain x-rays are the only imaging needed ; to rule out intrathoracic pathology, cervical spine pathology, first rib and clavicular abnormalities and cervical ribs. The abnormalities of the transverse process of seventh cervical vertebra, lengthening, enlargement and downwards peaking deformity, should be reported by the radiologist because they are very frequently found in patients with TOS.
Validity of the Diagnostic Triad
A new diagnostic test, “The Diagnostic Triad”, should consider the simplicity, intra and inter observer variability, and perhaps most importantly, the practical clinical value(66).
The validity of this triad rest in the following facts:
It is not present in any other disease or syndrome than TOS
Intra and inter observer variability are very low because of the simplicity of the maneuvers needed to elicit the signs.
The practical clinical value could be immense if this triad of signs is routinely performed in patients with upper extremity pain, neck and shoulder pain and/or paresthesias, noncoronary chest pains, vertebrobasilarly insufficiency symptoms and whiplash injury.
If this Triad of Signs, associated or not with the White Hand Sign, is found to be present, the diagnosis of TOS should be considered, it will be partially or totally responsible for the symptoms attributed to a different pathology.
1) Wilbourn AJ; Porter JM. Thoracic outlet syndromes. Spine.State of the Art Reviews.Sep1988;2(4):597-626
2) Edwards, DP, Mulkern E, Raja AN, Barker P. Trans-axillary first rib excision for thoracic outlet syndrome. J R coll Surg Edinb 1999; 44:362-365.
3) Huang JH, Zager EL. Thoracic outlet syndrome. Neurosurgery 2004; 55:897-902; discussion 902-3.
4) Jordan SE, Machleder HI. Diagnosis of thoracic outlet syndrome using electrophysiologically guided anterior scalene blocks. Ann Vasc Surg. 1998; 12:260-264.
5) Tolson RD. EMG for thoracic outlet syndrome. Hand Clin. 2004; 20:37-42, vi.
6) Novak CB. Thoracic outlet syndrome. Clin Plast Surg 2003; 30:175-178.
7) Sanders RJ, Hammond SC, Rao NS. Thoracic outlet syndrome. A review. The Neurologist 2008 Nov; 14:365-373.
8) Selmonosky CA, Byrd R, Blood C, Blanc JS. Useful triad for diagnosing the cause of chest pain. South Med J. 1981; 74:947-949.
9) Eslick GD, Talley NJ. Non-cardiac chest pain: Squeezing the life out of the australian healthcare system? Med J Aust. 2000; 173:233-234.
10) Brantigan CO, Ross DB. Diagnosing thoracic outlet syndrome. Hand Clin 2004 Feb; 20(1): 27-36.
11) Selmonosky CA. Thoracic outlet syndrome. The missing link in the diagnosis of non-coronary chest pain. Italian J. Card. 2008 Dec 9; E14:5217 ABSTRACT
12) Urschel HC Jr, Kourtis H, Jr. Thoracic outlet syndrome: a 50 year experience at Baylor University. Proc Bay Union Med Cent 2007 Apr; 20(2): 125-135.
13) Thompson JF, Jannsen F. Thoracic outlet syndrome. Br J Surg 1996; 83:435-436.
14) Karas SE. Thoracic outlet syndrome. Clin Sports Med 1990; 9:297-310.
15) Parziale JR, Akelman E, Weiss AP, Green A. Thoracic outlet syndrome, Am J Orthop 2000; 29:353-360.
16) Glockner SM. Shoulder pain, A diagnostic dilemma. Am Fam Physician. 1995; 51:1677-87, 1690-1692.
17) Wang FC, Crielaard JM. Entrapment neuropathies in sports medicine. Rev Med Liege. 2001; 56:382-390.
18) Safran MR. Nerve injury about the shoulder in athletes, part 2: Long thoracic nerve, spinal accessory nerve, burners/stingers, thoracic outlet syndrome. Am J Sports Med. 2004; 32:1063- 1076.
19) Thompson RW, Driskill M. Neurovascular problems in the athlete’s shoulder. Clin Sports Med 2006 Oct; 27(4): 769-802.
20) Sheth RN, Belzberg AJ. Diagnosis and treatment of thoracic outlet syndrome. Neurosurg Clin N Am. 2001; 12:295-309.
21) Roos DB. Thoracic outlet syndrome is underdiagnosed. Muscle Nerve. 1999; 22:126-9; discussion 137-138.
22)Atasoy E. Thoracic outlet compression syndrome. Orthop Clin North Am 1966 Apr; 27(2):265- 303.
23) Dragu A, Lang W, Ungalub F, Horch RE. Thoracic outlet syndrome: Differential diagnosis and surgical therapeutic options. Clin Surg 2009 Jan; 80(1):65-76.
24) Shukla PC, Carlton FB Jr. Diagnosis of thoracic outlet syndrome in the emergency department. South Med J 1966 Feb; 89(2):212-217.
25) Novak CB, Mackinnon SE, Patterson GA. Evaluation of patients with thoracic outlet syndrome. J Hand Surg (Am). 1993; 18:292-299.
26) Redenbach DM, Nelems B. A comparative study of structures comprising the thoracic outlet in 250 human cadavers and 72 surgical cases of thoracic outlet syndrome. Eur J Cardiothorac Surg. 1998; 13:353-360.
27) Juvonen T, Satta J, Laitala P, Luukkonen K, Nissinen J. Anomalies at the thoracic outlet are frequent in the general population. Am J Surg. 1995; 170:33-37.
28) Roos DB. Congenital anomalies associated with thoracic outlet syndrome. Anatomy, diagnosis and treatment. Am J Surg. 1976 Dec; 132(G1): 771-778.
29) Sallstrom J, Schmidt H. Cervicobrachial disorder in certain occupations, with reference to compression in the thoracic outlet. Am J Ind Med. 1984; 6:45-52.
30) Pascarelli EF, Hsu YP. Understanding work-related upper extremity disorders: Clinical findings in 485 computer users, musicians, and others. J Occup Rehabil. 2001; 11:1-21.
31) Magnusson T. Extra-cervical symptoms after whiplash trauma. Cephalalgia. 1994; 14:223-227; discussion 181-2.
32) Bacquey F. Haman M, Coskun O. et al. Rotational vertebrobasilar insufficiency secondary to a fibrous band of the longus colli muscle: Value of CT spiral angiography diagnosis. J Radiol. 2002; 83:979-982.
33) Harding CA, Poser CM. Rotational obstruction of the vertebral artery due to redundancy and extraluminal cervical fascial bands. Ann Surg. 1963; 158:133-137.
34) Sell JJ, Rael JR, Orrison WW. Rotational vertebrobasilar insufficiency as a component of thoracic outlet syndrome resulting in transient blindness. Case report. J Neurosurg. 1994; 81:617-619.
35) Kuether TA, Nesbit GM, Clark WM, Barnwell SC. Rotational Vertebral artery occlusion. A mechanism of vertebrobasilarly insufficiency. Neurosurgery. 1997 Aug; 41(2):429-433.
36) Dadsetan MR, Skerhut HE. Rotational vertebrobasilar insufficiency secondary to vertebral artery occlusion from fibrous band of the longus coli muscle. Neuroradiology. 1990; 32:514-515.
37) Wilbourn DJ. Thoracic outlet syndrome. Neuro Clin Aug 1999; 17:477-497.
38) Hug U, Jung FJ, Guggenheim M, Wedler V, Burg D, Kunzi W. “True neurologic thoracic outlet syndrome- anatomical features and electrophysiological long-term follow-up of lateral thenar atrophy. Handchir Mikrochir Plast Chir. 2006 Feb; 38(1):42-45.
39) Tender GC, Thomas AJ, Najeed MP, Kline DC. Gillat – Sammers hand revisited. A 25 year experience . Neurosurgery 2001 Oct; 55(4):883-890.
40) Pollak EW, ed. Thoracic Outlet Syndrome: Diagnosis and Treatment. Mount Kisco, N.Y.: Futura Publication Company; 1986.
41)Saunders RJ, Haug CE. Thoracic outlet syndrome: a common sequela of neck injuries. Philadelphia: Lippincott. 1991.
42) Addson A. surgical treatment for symptoms produced by cervical ribs and the scalenus anticus muscle. Surgery Gynecology and Obstetrics. 1947; 85:687.
43) Nord KM, Kapoor P, Fischer J, Thomas G, Sundaraman A, Scott K, Kothari MJ. False positive rate of thoracic outlet syndrome maneuvers. Electromyogr Clin Neurophysiol 2008 March; 48(2):67-69.
44) Mackinnon SE, Novak CB. Evaluation of the patient with thoracic outlet syndrome. Semin Thorac Cardiovasc Surg. 1996; 8:190-200.
45) Plewa MC, Delinger M. The false-positive rate of thoracic outlet syndrome shoulder maneuvers in healthy subjects. Acad Emerg Med. 1998; 5:337-342.
46) Rayan GM, Jensen C. Thoracic outlet syndrome: Provocative examination maneuvers in a typical population. J Shoulder Elbow Surg. 1995; 4:113-117.
47) Warrens AN, Heaton JM. Thoracic outlet compression syndrome: The lack of reliability of its clinical assessment. Ann R Coll Surg Engl. 1987; 69:203-204.
48) Patton GM. Arterial thoracic outlet syndrome. Hand Clin. 2004; 20:107-111, viii.
49) Becker MH, Lassner F. The asymptomatic thoracic outlet compression syndrome. Handchir Mikrochir Plast Chir. 2006; 38:51-55.
50) Remy-Jardin M; et al. Helical CT angiography of thoracic outlet syndrome: Functional anatomy. A J R 2000 June; 174:1667-1674.
51) Selmonosky CA, Poblete Silva R. The diagnosis of thoracic outlet syndrome Myths and Facts. Chilean J. of Surg. 2008 June; 60(3):255-261.
52) Selmonosky CA. The white hand sign. A new single maneuver useful in the diagnosis of thoracic outlet syndrome. Southern Medical Journal. 2002; 85:557. ABSTRACT
53)Vin F, Koskos F. Levy D, Goeai-Brissomiere BF. Thoracic outlet syndrome. Value of noninvasive studies. Presse_Med. 1986 Oct; 11, 15(34):1709-1714.
54) Youmans GR Jr, Smiley RA. Thoracic outlet syndrome with negative adson’s and hyperabduction maneuvers . Vasc and Endovasc Surg. 1980; 14(5):318-329.
55) Suderland S, ed. Nerve Injury. 2nd ed. NY:Edinburg NY Churchill Livingston; 1970 [1981 Printing].
56)Urschel HC, Kourlis H. Thoracic outlet syndrome; A 50-year experience at Baylor University Medical Center. 2007 April; 20:125-135.
57) Ozdemir O, Ozcakar L. Thoracic outlet syndrome: Another cause for unilateral palmar hyperhidrosis. Clin Rheumatol. 2007 Aug; 26(8):1375-1376.
58) Wilhelm A, Wilhelm F. Thoracic outlet syndrome and its significance for surgery of the hand (on the etiology and pathogenesis of epicondylitis, tendovaginitis, median nerve compression and trophic disorders of the hand). Handchir Mikrochir Plast Chir. 1985; 17:173-187.
59) Schubart PJ, Haeberlin JR, Porter JM. Intermittent subclavian venous obstruction: Utility of venous pressure gradients. Surgery. 1986; 99:365-368.
60) Sanders RJ, Hammond SL. Subclavian vein obstruction without thrombosis. J Vasc Surg. 2005; 41:285-290.
61) Vischel WC Jr, Patel AR. Surgery remains the most effective treatment for Paget-Schroetter syndrome: 50 year experience. Am Thor Surg 2008 Jul; 86(1):254-260.
62) DeLeon RA, Chang DC, Hassoun HT, Black JH, Rosenborough GS, Perier BA, Rotellini L, Cole D, Busse C, Freischlag JA. Multiple treatment algorithms for successful outcomes in venous thoracic outlet syndrome. Surgery. 2009 May; 145(60):500-507.
63) Snider HC, King GD. Minnesota multiphasic personality inventory as a predictor of operative results in thoracic outlet syndrome. South Med J. 1986; 79:1527-1530.
64) Axelrod DA, Proctor MC, Geisser ME, Roth RS, Greenfield LJ. Outcomes after surgery for thoracic outlet syndrome. J Vasc Surg. 2001; 33:1220-1225.
65) Brantigan CO, Ross DB. Diagnosis thoracic outlet syndrome. Hand Clinic. 2004 Feb; 20(1):27-36.
66) Knottnerus JA, van Weel C. Muris JW. Evaluation of diagnostic procedure. BMJ. 2002; 324:477-480.
67) De Georges R, Reynaud C, Becqnemier JD.Thoracic outlet syndrome surgery: long term functional results. Ann Vasc Surg. Sep 2004; 18(5) :558-565
68) Urschel HC,Patel A. Thoracic outlet syndrome. Curr Treat Options Cardiovasc Med.April 2003;5(2):163-168