Download Thoracic Outlet Syndrome

Thoracic Outlet Syndrome
Wilbourn’s Classification
1. Vascular
i. Arterial – major and minor
ii. Venous
2. Neurogenic
i. True
ii. Disputed
Arterial
 1-2%
 Acute events such as thrombosis easy to diagnose (pain, pallor, pulselessness and
parasthesia)
 May present with coolness of hand, claudication, unilateral Raynauds or fingertip
ulcerations
 Affected arm has a lower BP of >20mmHg difference (a reliable indicator of
arterial involvement)
 Full developed cervical rib seen in 50%
 Other 50% thought to have some other type of bony anomaly
Venous
 2-3%
 sudden effort induced thrombosis (Paget-Schroetter syndrome) or at rest with the
extremity in a compromised position for a prolonged period
 may develop large superficial collaterals with more chronic disease
 Acute cases present with cyanosis, swelling and pain
 Mostly seen in muscular young males after exercise
True Neurogenic
 1:1,000,000
 A typical patient is a young, thin female with a long neck and dropping shoulders
 usually C8-T1 distribution
 Hypothenar atrophy, decreased grip and sensation
 present as isolated hand intrinsic muscle atrophy without any pain (GilliatSumner hand)
Disputed Neurogenic
 Wide range of complaints
 No objective findings on electrodiagnostics or imaging.
Epidemiology
 Overall F>M 3.5:1
 Neurologic - Female-to-male ratio approximately 3.5:1
 Venous - More common in males than in females
 Arterial - No sexual predilection
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Much more common in countries where TOCS is a legitimate work related
condition
Some morphotypes predispose to the syndrome: poor muscular development,
droop of scapula, obesity and breast hypertrophy.
Anomalous cervical ribs seen in 0.17-0.74%, with a higher percentage of cervical
ribs in women
Anatomy
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3 areas of compression
1. interscalene triangle
2. costoclavicular triangle
3. pectoralis minor/subcoracoid space
most common compression sites in patients with TOS are within the scalene
triangle and the subcoracoid space
Interscalene Triangle
 Boundaries
1. Anterior – scalenius anterior
2. Posterior – scalenius medius
3. Inferior – 1st rib
 Compressed by
1. Cervical rib
 0.5% of population
 bilateral in 50-80%
 may be compressed by complete rib or anlage from incomplete rib
 Cervical rib growth is suppressed by full contribution of lower spinal
nerve roots to plexus – association between cervical ribs and a
prefixed plexus.
2. Abnormal scalene insertion
 V shape or U shape insertions of scalenius anterior and medius
 Increased downslope of 1st rib – more common in women
Costoclavicular space
 Boundaries
1. Anterior – clavicle, subclavius and costocoracoid ligament
2. Posteromedial – 1st rib
3. Posterolateral – superior border of scapula
 Compressed by
1. Hypermobile shoulder movements
2. Hypertrophied subclavius muscle
Subcoracoid space
 Compression by 3 mechanisms
1. Arm abduction stretches neurovascular bundle around coracoid
2. External scapular rotation – further stretches the same
3. Abduction also tenses the pectoralis minor tendon
Clinical
 Neurologic
 Chronic insidious pain involving shoulder girdle, neck and upper back
 Pain, particularly in the medial aspect of the arm, forearm, and the ring and
small digits
 Paresthesias, often nocturnal, awakening the patient with pain or numbness
 Loss of dexterity
 Cold intolerance
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 Headache
Venous
 Pain, often in younger men and often associated with strenuous work
Arterial
 Pain
 Claudication
 Often in young adults with a history of vigorous arm activity
Examination
 Posture
 Slouch forward
 Large breasted
 Shoulder droop
 Masses in supra/infraclavicular fossae
 Percussion test
 Sensation
 Dermatomal
 Motor
 Reflexes
 Provocative Tests
 In general unreliable as 90% of asymptomatic patients will be positive
 neurological response (paresthesias) appears more valuable than the vascular
response (reduced radial pulse intensity). The most predictive maneuver seems
to be the abduction/external rotation of the arm
1. Adson’s test / scalene test
 With arm at side, patient hyperextends neck, turns face towards affected
side and inhales deeply
 Test
 Positive test = diminution or obliteration of radial pulse
2. Halstead Maneuver/costoclavicular test
 Both arms at side, patient moves shoulders downwards and backwards –
protruding chest to draw clavicle against 1st rib
 test was modified by Halstead to include downward traction of the
patient's arms by the examiner and monitoring of the radial pulse
3. Wright’s Hyperabduction Maneuver
 Arm is externally rotated and abducted 180 and patient inhales
 Only flex elbow minimally (minimise cubital tunnel)
 Positive if symptoms occur <1min
 Indicated subcoracoid impingement
4. Roo’s/ EAST test
 90 abduction and external rotation (stick-up test)
 pumps hands open/close quickly for 3 minutes
 evaluates all 3 types of thoracic outlet syndrome
 Positive test if reproduce symptoms or rapid fatiguibility
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Although a single positive test is probably meaningless, more than 2 positive
responses is significant and should be combined with history, other findings and
diagnostic studies
Scalene muscle block-temporary relief of symptoms following anterior scalene
muscle infiltration with 4 cc of 1% lidocaine appears a useful diagnostic tool for
TOS. Furthermore, there isa high correlation between good response to the block
and improvement following scalenectomy.
Investigations
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Xrays
 Cervical spine
 Chest
Color flow duplex scanning
 92% sensitive in vascular TOCS
CT
 Useful to help rule out other pathologies (Pancoast tumor, disc prolapse)
Arteriogram (indications)
 Evidence of peripheral emboli in the upper extremity
 Suspected subclavian stenosis or aneurysm (eg, bruit or abnormal
supraclavicular pulsation)
 Blood pressure differential greater than 20 mm Hg
 Obliteration of radial pulse during EAST
Venography (indications)
 Persistent or intermittent edema of the hand or arm
 Peripheral unilateral cyanosis
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Prominent venous pattern over the arm, shoulder, or chest
Identification of significant collaterals may help with operative planning, and
may determine the type of exposure used in order to limit damage to these
collaterals
Electrophysiology
 Nerve conduction evaluation via root stimulation and F wave is the best direct
approach to evaluation of neurologic TOS.
 Electromyography (EMG) is unreliable and does not provide objective
evidence of TOS.
Management
Nonoperative
 First line treatment in disputed neurogenic type
 Arterial type unlikely to respond
 Physical therapy
 Postural exercises, stretching, abdominal breathing used to relieve muscular
tension and pain are beneficial.
 Pain control
 Medications
 TENS
 Heat/ice packs
 Approximately 60% of patients improve significantly with conservative treatment
alone and avoid surgery
 The indication for surgical treatment of neurogenic TOS is the failure of
conservative treatment in a patient with disability so severe that the patient is
unable to work or live comfortably.
 Most physicians prescribe 3-12 months of physical therapy prior to considering
surgical decompression of the thoracic outlet.
 venous TOS–related effort thrombosis that relies on anticoagulation and arm
elevation leaves 74% of patients with residual disability and 12% with significant
complication.
 Thrombolytic therapy generally is preferred over venous thrombectomy;
however, thrombectomy still may have a role in some cases with low surgical
risk and contraindication to thrombolytic therapy.
 Although thrombolytic therapy alone is superior to simple anticoagulation in
patients who present with venous TOS, the patients who achieve the best
results are those who are treated with thrombolytics and surgical
decompression.
Surgical
Indications
1. Impending or acute vascular catastrophe (vascular TOS)
2. Intractable pain
3. Failure of conservative treatment
4. Significant neurologic deficit
Approaches
1. Transaxillary
 Most used, popularised by Roos
 a transverse incision is made over the 3rd rib just inferior to the axillary
hairline and deepened between the pectoralis major and the latissimus dorsi to
the chest wall.
 Preserve intercostobrachial nerve
2. Supraclavicular
 horizontal incision is made parallel and 2cm above the clavicle, extending
from the sterno-cleido-mastoid muscle (SCM) to the anterior border of the
trapezius
 infraclavicular counter-incision can be performed for added exposure
 After platysma incision, the clavicular head of SCM is either retracted
medially or incised and then repaired at the end of operation.
 The supraclavicular pad of fat, of varying bulk, is dissected from below
upward; the omo-hyoid muscle is incised; the cervical transverse vessels may
be ligated. One reaches the plane of the anterior scalene muscle; the phrenic
nerve coursing obliquely on the surface of the muscle must be protected in
order to perform the anterior scalenectomy.
 Beware risk of phrenic (lateral to medial over scalenius anterior) and long
thoracic nerve (exits posterior border of scalenius medius) injury
3. Posterior subscapular
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incision between the medial border of the scapula and the cervicodorsal
spinous processes, division of trapezius and rhomboid muscles, exposure of
the posterior upper rib cage, resection of 1st rib and of posterior and middle
scalene muscles. The BP is approached from behind, at the level of spinal
nerves and trunks.
This approach, extensive in regard to muscle incision, is reserved to
"complicated TOS"
Surgical recommendations
1. Excise and release all anomalous anatomy
2. Resection of 1st rib
3. Release /excision of anterior/middle scalene
4. Neurolysis of brachial plexus as indicated
Arterial TOS
 Supra/infraclavicular approach. Transaxillary does not give adequate exposure
 Need to excise anomalous rib and arterial reconstruction as required
Venous TOS
 Thrombolysis followed by 1st rib resection
 For occlusions older than 10-14 days, chances for a successful thrombolysis are
poor
 A lesion longer than 2 cm may require venous bypass or a jugular vein turndown
procedure. A consensus statement favored conservative treatment with
anticoagulation under these circumstances and concluded that venous bypass
should be reserved for only those patients with disabling symptoms and serious
complications.
Neurogenic TOS
 Removing the anomaly
 Release/remove anterior and middle scalene
 Excise 1st rib
Complications
1. Recurrence 5-25%
 Lowest recurrence in those undergoing combined 1st rib resection and
scalenectomy
2. Nerve injuries
 Phrenic, long thoracic, and sympathetic nerves
3. lymph leak
4. bleeding