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Thoracic outlet syndrome

  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.
  6. 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.
  7.  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
  8.  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
  9.  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.
  10.  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
  11.  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
  12.  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
  13.  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
  14. 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.
  15. 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.
  16. 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
  17. 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
  18. Neurogenic TOS is classically associated with certain provocative tests,
  19. venous collaterals in left anterior chest in a patient with subclavian thrombosis (Paget- Schroetter syndrome
  20.  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
  21.  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)
  22.  Cervical myelogram, CT scan, or MRI may be appropriate for patients suspected of having cervical disk disease or spinal cord disease.
  23. 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
  24.  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.
  25.  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
  26.  Scalenotomy  Scalnectomy  Pectoralis minor tenotomy
  27. surgery  Supraclavicular approach  Ideal for removal of a cervical rib or a fibrous remanant and allows inspection of artery
  28. Infraclavicular approach  Idael for venous and arterial obstruction  Venous embolectomy  Arterial reconstruction
  29. Video assisted thorasic surgery  First rib resection
  30. Complications intraoperative  Nerve injury  Brachial plexus  Long thorasic nerve  Phrenic nerve  Vascular injury  Subclavian artery and vein
  31. Recrrent tos  Occurs in 10%  Recur in 1 months to 7 years in treated nonoperatively