Thoracic outlet syndrome (TOS) refers to compression of the neurovascular structures in the thoracic outlet. There are two main types - neurogenic and vascular. Neurogenic TOS is more common and involves compression of the brachial plexus nerves, while vascular TOS involves compression of the subclavian artery or vein. Symptoms vary depending on the affected structure but may include pain, numbness, cold intolerance, or vascular symptoms like swelling. Diagnosis involves physical exam maneuvers and imaging tests like ultrasound or MRI. Treatment begins with conservative measures like stretching and strengthening, but refractory cases may require injections or surgeries like scalenectomy to decompress the area.

1. Thoracic outlet
syndrome

2.  Thoracic outlet syndrome (TOS) is a broad term that refers to
compression of the neurovascular structures in the area just
above the first rib and behind the clavicle.
 The brachial plexus (95%), subclavian vein (4%), and subclavian
artery (1%) are affected.

3. Wilbourn's Classification
 two basic types of TOCS and four subtypes
 The two basic types are vascular and neurogenic.
 The vascular type is further divided into arterial and
venous subtypes,
 The neurogenic type has been subdivided into "true“
neurogenic and non specific

4. Neurogenic TOS accounts for more than 90%
of all TOS cases, whereas vascular TOS
constitutes 3% to 4% of all cases.

5.  Most TOS cases are seen in adults between the ages of 20 and 50 years.
 Vascular TOS is seen equally in nonathletic men and women,
 but neurogenic TOS is three to four times more likely to occur in women than in men.

7. Interscalene triangle
 the most important of these passageways is the interscalene triangle,
which is also the most proximal.
 this triangle is bordered by
 the anterior scalene muscle anteriorly,
 the middle scalene muscle posteriorly,
 and the first rib inferiorly.
 this area become smaller with certain provocative maneuvers.
anomalous structures, such as fibrous bands, cervical ribs, and
anomalous muscles, may constrict this triangle further.

8.  contains the vast majority of neurovascular compression cases
 It is crossed by
 Subclavian artery (which occupies the floor of space)
 Three trunks of brachial plexus (upper, middle & lower)
 Subclavian vein runs beneath the anterior scalene muscle and doesn’t cross
interscalene triangle

9.  the costoclavicular triangle, bordered
 anteriorly by the middle third of the clavicle,
 posteromedially by the first rib,
 posterolaterally by the upper border of the scapula.
 Contains subclavian artery, vein & 3 cords of brachial plexus
 The retropectoralis space lies inferior to the coracoid process beneath the
pectoralis minor tendon.
 Same except the cord divides into 5 terminal branches

11.  Cervical rib-usually arises from the seventh cervical
vertebra. and rarely c6.Usually symmetrical on two sides,
sometimes assymetrical and rarely unilateral. more
common in females. It is relationship of neurovascular
bundle structure with cervical rib that may cause
symptoms.
 Fisrt thoracic rib – a first thoracic rib can cause
compression if it is unusually high, large or irregularly
curved.
 A deformed thoracic outlet as a result of sloping shoulders ,scoliosis and
fracture of first rib can also compress the neurovascular structures
against the first rib.

12.  Clavicle – clavicle along with subclavius muscle forms the
anterior wall of cevicoaxillary passage.
 normally clavicle is curved forwards in its medial 2/3.congenital
flattening or malunion cause narrowing of this passage and compression

13.  Congenital malformations- associated conditions
 Scoliosis
 Syringomyelia
 Klippel feil syndrome
 Sprengel shoulder
 Scalenus anterior – hypertrophy of the muscle due to shouldr descent ,
spasm of the muscle due to mild irritation of brachial plexus holds the
first rib higher and thus cause narrowing of scalenic hiatus
 Scalenus medius- hypertrophy , spasm and abnormal insertion on first
rib or its fusion with anticus can cause narrowing of scalenic hiatus

14.  Pectoralis minor- persons working with the arms hyperabducted or sleeping
with the arms over the head develop paresthesia as a result of compression of
neurovascular bundle by pectoralis minor and coracoids
process(hyperabduction syndrome)
 Hypertrophied subclavius
 Tight omohyoid muscle- this is important in long necked people causing
compression of brachial plexus,as it may run diagonally across brachial plexus
 Congenital fibromuscular bands are noted in as many as 80% of patients with
neurologic TOS

15.  Trauma or repetitive activities
 Motor vehicle accident hyperextension injury, with subsequent fibrosis and scarring
 Effort vein thrombosis (ie, spontaneous thrombosis of the axillary veins following
vigorous arm exertion)
 Playing a musical instrument: Musicians can be particularly susceptible owing to
their need to maintain the shoulder in abduction or extension for long periods

16. Clinical features
 Neurologic symptoms occur in 95% of cases. The lower 2 nerve roots of the
brachial plexus, C8 and T1, are most commonly (90%) involved, producing
pain and paresthesias in the ulnar nerve distribution.
 The second most common anatomic pattern involves the upper 3 nerve roots
of the brachial plexus, C5, C6, and C7, with symptoms referred to the neck,
ear, upper chest, upper back, and outer arm in the radial nerve distribution.

17. neurologic
 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
 Cold intolerance
 Occipital headache
 Weakness
 Raynaud phenomenon, hand coldness, and color changes may also be seen, usually due to an
overactive sympathetic nervous system as opposed to ischemia.
 Most have a history of neck trauma preceding their symptoms, most commonly from auto
accidents and repetitive stress at work.

18. arterial
 Pain
 Claudication
 Pallor
 Coldness
 Paresthesias
 Often in young adults with a history of vigorous arm activity
 Symptoms usually develop spontaneously from arterial emboli
 Easily fatigued arms and hand

19. venous
 Pain, often in younger men and often preceded by excessive activity in the
arms
 Swelling of the arm
 Cyanosis
 Paresthesias in the fingers and hand (may be secondary to swelling as opposed to
nerve compression)
 Superficial vein distensions
 Paget schroetter syndrome

20. Neurogenic TOS is classically associated
with certain provocative tests,

25. venous collaterals in left anterior chest in a patient with
subclavian thrombosis (Paget-
Schroetter syndrome

26.  Cervical radiography - May demonstrate a skeletal abnormality
 Chest radiography
 Cervical or first rib: This is usually associated with the arterial form of TOS but also
can be a predisposition to developing the neurologic form following neck trauma.
 Clavicle deformity
 Pulmonary disease
 Pancoast tumor

27.  Color flow duplex scanning for suspected vascular thoracic outlet syndrome (TOS)
 Arteriography (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
 Prominent venous pattern over the arm, shoulder, or chest
 Other Test
 Nerve conduction evaluation via root stimulation and F wave is the best direct approach to evaluation of
neurologic TOS.
 Electromyography (EMG)

28.  Cervical myelogram, CT scan, or MRI may be appropriate for patients suspected
of having cervical disk disease or spinal cord disease.

31. treatment
 In majotiy of pts conservative management will effect in improvement or
complete relief of symptoms
 Initial management consists of
 Weight reduction
 Exercise programme directed towards improving posture,strengthening
shoulder muscles and avoiding hyperabduction

32.  Stretching
The goal of self stretching is to relieve compression in the thoracic cavity,
reduce blood vessel and nerve impingement, and realign the bones, muscles,
ligaments, and tendons causing the problem.
 Moving shoulders forward (hunching) then back to neutral, followed by extending
them back (arching) then back to neutral, followed by lifting shoulders then back
to neutral.
 Tilting and extending neck opposite to the side of injury while keeping the
injured arm down or wrapped around the back.

33.  Invasive
 Cortisone
Injected into a joint or muscle, cortisone can help relief and lower
inflammation
 Botox injections
Short for Botulinum Toxin A, Botox binds nerve endings and prevents the
release of neurotransmitters that activate muscles. A small amount of Botox
injected into the tight or spastic muscles (usually one or all three scalenes)
found in TOS sufferers often provides months of relief while the muscle is
temporarily paralyzed

34.  Scalenotomy
 Scalnectomy
 Pectoralis minor tenotomy

35. surgery
 Supraclavicular approach
 Ideal for removal of a cervical rib or a fibrous remanant and allows inspection
of artery

36. Infraclavicular approach
 Idael for venous and arterial obstruction
 Venous embolectomy
 Arterial reconstruction

37. Video assisted thorasic surgery
 First rib resection

38. Complications intraoperative
 Nerve injury
 Brachial plexus
 Long thorasic nerve
 Phrenic nerve
 Vascular injury
 Subclavian artery and vein

39. Recrrent tos
 Occurs in 10%
 Recur in 1 months to 7 years in treated nonoperatively