THORACIC OUTLET SYNDROME

Dr. Nanda gopal Velagapudi

Dr. Avinash KatkamDr Giridhar Boyapati

First clinical description given by A.Cooper 1821

W H Willshire described about cervical rib

H Coote first resection of cervical rib.

In 1956 Peet introduced the term thoracic outlet syndrome.

Definition

• Thoracic outlet syndrome (TOS)- a collection of symptoms brought about by abnormal compression of the neurovascular bundle by bony, ligamentous or muscular structers in the narrow space between clavicle and 1st rib – the thoracic outlet.

• Boundaries of TO

• posteriorly: T1 vertebral body

• laterally: first rib and costal cartilage

• anteriorly: manubrium sterni

ANATOMY

Interscalene triangle− Inferiorly : 1st rib− Ant : scaleneus

anterior− Post : scaleneus

medius.

Costoclavicular spaceAnt : clavicle,

subclavius muscle

Post medial: 1st rib

Post lateral: superior border of scapula.

contents• viscera

– thymus– trachea– oesophagus– lung apices

• vessels, nerves and lymphatics– common carotid arteries– confluences of internal

jugular and subclavian veins

– phrenic nerves– vagus nerves– recurrent laryngeal nerves– thoracic duct

• prevertebral fascia• muscles

– sternocleidomastoid muscle

– anterior and middle scalene muscles

– sternohyoid muscle

– sternothyroid muscle

Interscalene triangle

Costoclavicular space

Subcoracoid area

Anatomic sections show the compartments of the thoracic outletAnatomic sections show the compartments of the thoracic outlet

Demondion X et al. Radiographics 2006;26:1735-1750

Fig. (b) Section obtained after removal of the pectoralis minor muscle shows the neurovascular bundle. C = clavicle, straight black arrow = axillary artery, curved black arrow = axillary vein, white arrow = brachial plexus.

Anatomic sections show the compartments of the thoracic outlet

Demondion X et al. Radiographics 2006;26:1735-1750

Fig. Anatomic sections show the compartments of the thoracic outlet. (a) Section obtained after removal of the pectoralis major muscle shows the costoclavicular space (red oval) and retropectoralis minor space (yellow oval). Pmi = pectoralis minor muscle.

• Race No racial predilection exists.• Sex Thoracic outlet syndrome is traditionally

more common in women than in men, with a female-to-male ratio as high as 3:1.

• Age Thoracic outlet syndrome is most common

in people aged 10-50 years

Principal Causes of TOS

Cervical rib

Cervical rib

• It is a superneumary rib that arises from seventh cervical rib or rarely from sixth or fifth cervical vertebrae.

• incidence 0.5-0.6%

• Bilateral in 60-80 %

• Symptomatic in 10 -15%

types

• Type1 small projection from costal faset. Less than 2.5cm

• Type 2 projection beyond transverse process. > 2.5cm

• Type 3 nearly complete rib which is partly fibrous

• Type 4 complete rib with costal cartilage attached to 1st rib or sternum.

Classification

Subgroup 1Subgroup 1 - - ((neurologic neurologic typetype))

• –95% of cases This type is secondary to compression

of the brachial plexus caused by various soft tissue and bony abnormalities at the point where the nerves pass between the anterior and middle scalene muscles.

Subgroup 2 - (the venous type):

• 3-4% of cases. Venous thrombosis may be categorized into primary and secondary thrombosis based on the etiology.

Primary venous thoracic outlet syndrome, or primary venous thrombosis, is also called Paget-Schrötter syndrome named after the 2 individuals who first described this entity: Paget, who described it in 1875, and von Schrötter, in 1884.

Subgroup 3Subgroup 3 ( (the arterial type):

• 1-2% of cases. This type is associated with the most

serious complications, including limb ischemia (which may result in the loss of the affected upper extremity).

Neurogenic TOS• Etiology

– Hyperextension neck injury (whiplash)

– Repetitive stress injuries

Neurogenic TOS• Predisposing Factors

– Scalene muscle anomalies

– Narrow scalene triangles

– Congenital ligaments/bands

– Cervical ribs

Neurogenic TOS• Pathophysiology

– Neck trauma stretches and tears scalene muscle fibers

– Swelling of muscle belly pain, parathesias, numbness, weakness

– Scarring/fibrosis of muscle belly occipital headaches.

• Symptoms

– Pain, parathesias, numbness, weakness throughout affected hand/arm

• Not necessarily localized to peripheral nerve distribution

– Extension to shoulder, neck, upper back

– “Upper plexus” disorders

– “Lower plexus” disorders

Neurogenic TOS• Symptoms

– Occipital headaches

– Perceived muscle weakness

• Actual weakness and atrophy are rare

– Vasomotor symptoms

• Vasospasm, edema, hypersensitivity (CRPS)

Neurogenic TOS• Pectoralis minor syndrome

– Compression of neurovascular bundle under the pec minor

– Pain over anterior chest and axilla

– Fewer head/neck symptoms

Venous TOS• Etiology

– Developmental anomalies of costoclavicular space

– Repetitive arm activities – throwing, swimming, overhead activities.

Venous TOS• Predisposing Factors

– Relationship of vein to subclavius tendon and costoclavicular ligament

– Decrease in dimensions of costoclavicular space

• Repetitive trauma to vein causing stenosis, thrombosis

• Acute occlusion

– Pain

– Tightness

– Discomfort during exercise

– Edema

– Cyanosis

Increased venous pattern

Tenderness over the axillary vein

Gangrene rarely

Arterial TOS• Etiology

– Cervical or anomalous first rib

– Anomalous anterior scalene insertion

Arterial TOS• Pathophysiology

– Arterial compression resulting in post-stenotic dilatation or aneurysm

– Distal embolization of thrombus

Interscalene triangle Artery , Nerves

Costoclavicular space Vein

Subcoracoid area Artery, Vein , Nerves

Arterial TOS

• Symptoms

–Digital or hand ischemia

–Cutaneous ulcerations

–Forearm pain with use–Pulsatile supraclavicular mass/bruit

DIAGNOSIS

• Clinical maneuversClinical maneuvers• RadiographyRadiography• UltrasonographyUltrasonography • Magnetic resonance (MR) angiographyMagnetic resonance (MR) angiography• Computed tomographic (CT) (CT)

angiograangiographyphy• Angiography and venographyAngiography and venography

Adson maneuver

Patient is instructed to take and hold a deep breath and extend his neck fully and then asked to turn his head towards the side being examined. Obliteration or diminuation in the radial pulse suggest compression.

TThhe Roos teste Roos test

• The patient repeatedly clenches and unclenches the fists while keeping the arms abducted and externally rotated (palms forward and upward). The elbows are braced slightly behind the frontal plane for 3mins.

• The test is positive when symptoms are reproduced with this maneuver.

• A positive test is very suggestive of the thoracic outlet syndrome.

Hyperabduction maneuver

• Evaluates compression of the neurovascular bundle between the coracoid process and the pectoralis minor muscle.

• The patient externally rotates the shoulders and extends the arms out from the chest and then above the head.

Wright's hyperabdution test

Halsted's Costoclavicular maneuver

• Evaluates compression of the neurovascular bundle between the clavicle and the first rib.

• The patient assumes an exaggerated military position with shoulders pushed backward and pressed downward.

Diagnosis and Treatment

Diagnosis• “the most accurate diagnosis of TOS…must

rely on a careful history and thorough, appropriate physical examination”

» David B Roos, MD

• No single diagnostic test has sufficient specificity to prove or exclude the diagnosis

DD nTOS• Carpal tunnel syndrome

• Ulnar nerve compression or neuritis.

• Rotator cuff tendinitis

• Cervical spine strain/sprain

• Fibromyositis

• Cervical disk disease

• Cervical arthritis

• Brachial plexus injury

DD aTOS• Other sources of emboli: Cardiac and aortic

arch causes, coagulopathies

• Vasculitis

• Radiation-induced arteritis

• Connective tissue disorders

• Arterial dissection

• Atherosclerotic disease

• Traumatic

Imaging• X-rays

– Cervical rib

– Elongated C7 transverse process

– Hypoplastic 1st rib

– Callous formation from clavicle or 1st rib fracture

– Pseudoarthrosis of 1st rib

• Unable to image soft tissue anomalies and fibromuscular bands – seen only at time of surgery

• CT/MRI can rule out other pathologies

• Magnetic resonance (MR) angiographyMagnetic resonance (MR) angiography and computed tomographic (CT) angiography(CT) angiography of the thoracic inlet, especially with recently devised techniques and protocols, are noninvasive modalities that provide image quality comparable to that of angiography and venography.

• Angiography and venographyAngiography and venography remain the criterion standards for the radiologic diagnosis of these conditions, and they have the added benefit of enabling potential endovascular treatment.

• MR neurography – newer technology to detect localized nerve function abnormality

• aTOS

– Segmental arterial pressures

– Angiography

• vTOS

– Duplex U/S

– Venography

• Consider bilateral studies

EMG/NCS• Reduction in NCV and low amplitude motor

responses

• Positive results

– Confirms the clinical diagnosis

– Poor prognosis if true neural damage present

• Negative results

– Does not exclude TOS

Both EMG/NCV have lo sensistivity for TOS

Electrophysiology Testing• Medial antebrachial cutaneous nerve (MAC)

– Lowest branch of inferior trunk of brachial plexus

– More sensitive to compression than other branches

• Higher sensitivity and specificity with EMG/NCS

Scalene muscle block• Most useful when diagnosis is unclear

• Patient in supine position with neck hyperextended and turned to opposite side. Lateral border of sternocledomastoid is palpated andabout 1.5 inches above the clavicle anterior scalene muscle is palpated.

• 5- 7ml of plane bupivacaine and 1ml of betamethasone is injected.

• Relief of symptoms ranging from few days to weeks.

• Good relief of symptoms confirms the diagnosis.

• 2-3 injections can be given.

TreatmentConservative management aims to increase the

space in the thoracic outlet area and to relieve compression on the neurovascular structures.

Step 1 proper postural changes and correct faulty postures.

Step 2 manipulate and mobilize and relax 1st rib and clavicular, scapular, pectoral muscles.

Step 3 strengthen the shoulder girdle muscles and stretch scalene muscles

Pain control

• Muscle relaxants

• NSAIDS

• Ultrasonography with ionatophorosis

• Transcutaneous electric nerve stimulation. (TENS)

• Local anesthetic injections.

Edema control

• Edema gloves

• Compressive garments

• Elevation of limb

• Active range of motion exercises

• Retrograde massages

• Phonophoresis controls pain and edema

Ergonomics • Work posture related changes

• Relative adjustment of chair height so that forearm rests comfortably and without shoulders being elevated or depressed.

• Avoid carrying heavy weights on effected side

• Avoid hyperextension of neck and hyperabducting postures

Exercises Involves relaxing shoulder girdle and stretching the scalene and pectoral muscles.

Neck : neck side bending exercises

neck rotation

neck flexion exercises

Shoulder : shrugging of shoulders

pendulum exercises

Treatment nTOS

• Neck stretching

• Posture correction

• Avoid neck traction, weights, resistance exercises, strengthening exercises

Surgical decompression

Symptoms persists beyond 2 months of conservative management. Associated vascular compression with poststenotic dialatation.Complete occlusion of a large vessel.Progression of neurological symptoms.Nerve conduction velocity < 60m/s

• 1st rib resection and scalenectomy are standard procedures for TOS

• 1st rib resection is recommended for lower type TOS

• Scalenectomy is recommended for upper type TOS

• Best results and less chance of recurrence with combined 1st rib resection and scalenectomy.

Scalenectomy • Incision :8cms incision, 1.5cm above middle

third of clavicle.• 80-90% of scalenus anterior muscle and

40-50% of scalenus medius muscle removed.

Protect long thoracic nerve and phrenic nerve.

Complications : neck hematoma, chylus drainge, dyspnea due to phrenic nerve irritation.

1st rib resection

1. Transaxillary approach

2. Supraclavicular approach

3. Infraclavicular approach

4. Posterior approach.

Transaxillary approach ( Roos approach)

• Transverse Incision at the level of third rib just below the axillary hair line.

– Advantages

• Limited field of operative dissection

• Cosmetically placed incision

• Achieve 1st rib resection and anterior scalenectomy

• Removal of anomalous ligaments and fibrous bands.

• Less blood loss, no muscles are divided.

– Disadvantages

• Incomplete exposure of entire scalene triangle

• Difficulty achieving brachial plexus neurolysis

• Limited if vascular reconstruction is needed

• Supraclavicular approach

– Advantages

• Wide exposure of all anatomic structures

• Permits complete resection of anterior and middle scalenes as well as brachial plexus neurolysis.

• Allows resection of cervical ribs and anomalous 1st ribs

• Vascular reconstruction is possible

Infraclavicular approach

• ADVANTAGES• Ideal for venous and arterial obstruction.• Venous embolectomy.• Arterial reconstruction.

• DISADVANTAGES• Poor view of thoracic outlet.• Poor excision of posterior part of the rib.

Posterior approach

• Advantages

• cervical rib can be easily resected.

• Sympathetectomy can be done

• Disadvantages

• Vascular reconstruction can not be performed.

Thoracoscopic First Rib Resesction

• Three 10mm portal are made

-1st anterior 3rd ICS

-2nd lateral 5th ICS

- 3rd lateral wall of 6th ICS

Endoscopic drill is used to dissesct the rib

Adjunctive procedures

– Pectoralis minor tenotomy.

– Sympathectomy :

Treatment vTOS• Anticoagulation therapy with heparin and oral

anticoagulants.

• Fibrinolytics

• Catheter-directed thrombolysis.

• Thrombosis is < 3days old : Thrombectomy

• Chronic thrombosis : Venous Bypass

Complications• Nerve injury

bracial plexus injury

Long thoracic nerve of bell

Phrenic nerve

Intercostobrachial nerve.

Vagus and Reccurent laryngeal nerve

Vascular injury

Subclavian vein and artery

• Thoracic duct injury

Lymphatic fistula

Lymphocele

Chylothorax

Pleural complication

pleural damage

Pneumotharax

Pleural effusion

Recurrent nTOS• Postoperative scarring most common cause.

• Recurrence usually is seen within 3months.

• To minimize scar tissue formation patient is instructed to perform active range of motion exercises beginning the day after surgery. Performed every 3-4 hrs for atleast 6 months.

Initial procedure

Recurrent procedure

Adequate 1st rib resection

scalenectomy

More than 1cm of first rib stump.

Removal of the stump Brachial plexus neurolysisSubclavian vessel vascolysis.Partial resection of 2nd ribscalenectomy

1st rib resection +Scalenectomy

Brachial plexus neurolysis.Adequate coverage of plexus with prescelene fat.Partial 2nd rib resection.

Thank you.