Orthopaedic Surgery - Thoracic Outlet Syndrome

Basics

Thoracic outlet syndrome, or:

TOS

is a clinical disorder caused by compression of:

Neural

or

Vascular structures

supplying the upper extremity as they pass through the:

Thoracic outlet

and adjacent:

Supraclavicular region.

Structures Involved

The principal structures at risk are the:

Brachial plexus

Subclavian artery

and

Subclavian vein.

Synonyms

Historical terms include:

Scalenus anticus syndrome

Costoclavicular syndrome

and

Cervical rib syndrome.

Major Clinical Types

Thoracic outlet syndrome is generally divided into:

Neurogenic TOS

Venous TOS

and

Arterial TOS.

Neurogenic disease is by far the most common form.

Neurogenic Thoracic Outlet Syndrome

Neurogenic TOS results from compression or irritation of the:

Brachial plexus.

Symptoms commonly include:

Pain

Paresthesia

Numbness

and occasionally:

Weakness.

Venous Thoracic Outlet Syndrome

Venous TOS results from compression or thrombosis involving the:

Subclavian or axillary vein.

It may produce:

Arm swelling

Cyanosis

and

Venous congestion.

Arterial Thoracic Outlet Syndrome

Arterial TOS results from compression or injury of the:

Subclavian artery.

It may produce:

Coolness

Fatigue

Ischemic pain

or distal:

Embolic symptoms.

Epidemiology

Thoracic outlet syndrome is relatively:

Uncommon.

Incidence

Historical estimates vary widely, approximately between:

0.03% and 0.8%.

The fully developed syndrome is considerably less common than nonspecific:

Upper-extremity pain or paresthesia.

Age

Thoracic outlet syndrome occurs most commonly in:

Young to middle-aged adults.

Sex

It is reported more frequently in:

Women

than in men.

Risk Factors

Potential predisposing factors include:

Cervical ribs

Congenital fibrous bands

Abnormal first-rib anatomy

and disorders that increase susceptibility to:

Peripheral nerve dysfunction.

Systemic Conditions

Associated systemic conditions include:

Diabetes mellitus

Thyroid disease

and

Alcohol-related neuropathy.

These disorders may make peripheral nerves more vulnerable to:

Compression.

Aggravating Factors

Symptoms may be worsened by:

Obesity

Postural abnormalities

Repetitive overhead activity

and prolonged positions that narrow the:

Thoracic outlet.

Shoulder-Girdle Position

A chronically depressed or forward-positioned shoulder girdle may decrease available space for the:

Brachial plexus

and

Subclavian vessels.

Etiology

Thoracic outlet syndrome is often:

Multifactorial.

Potential contributors include:

Trauma

Repetitive occupational activity

Congenital anatomy

Postural abnormalities

and systemic:

Neuropathic disease.

Overhead Activity

Occupations requiring prolonged:

Overhead arm use

such as ceiling painting may provoke symptoms over a relatively:

Short period.

Repetitive Lower-Elevation Activity

Occupations involving repetitive upper-extremity motion without extreme elevation may also contribute over:

Many years.

Examples include prolonged:

Keyboard use

or

Driving.

Double-Crush Phenomenon

Thoracic outlet syndrome may coexist with more distal nerve-compression disorders such as:

Carpal tunnel syndrome

or

Cubital tunnel syndrome.

Concept of Double Crush

The double-crush concept proposes that a nerve compromised proximally may become more susceptible to compression at another point along its:

Course.

This theory remains clinically relevant but does not explain every patient with multiple:

Entrapment neuropathies.

Associated Conditions

Patients with:

Diabetes mellitus

Thyroid disease

Alcohol-related neuropathy

and systemic arthritis may have increased susceptibility to:

Multiple nerve-compression syndromes.

Diagnosis

The diagnosis is primarily:

Clinical.

No single provocative maneuver or diagnostic test can reliably confirm or exclude:

Thoracic outlet syndrome.

Signs and Symptoms

Symptoms depend on whether the primary compression is:

Neural

Arterial

or

Venous.

Neurogenic Symptoms

Patients may report:

Neck pain

Shoulder pain

Arm pain

Paresthesia

or

Numbness.

Distribution

Symptoms may involve the entire:

Upper extremity

but commonly predominate along the:

Ulnar side of the forearm

and the:

Ring and small fingers.

The middle finger may occasionally also be involved.

Sensory Findings

Objective sensory abnormalities are often:

Subtle.

They may involve the:

Ulnar aspect of the hand

and sometimes the:

Medial forearm.

Nocturnal Symptoms

Night pain and paresthesia may occur.

These symptoms should be distinguished from:

Carpal tunnel syndrome

which more often affects the:

Thumb

Index finger

Middle finger

and radial half of the:

Ring finger.

Overhead Intolerance

A common complaint is difficulty using the arm in an:

Elevated or overhead position.

Symptoms may increase during:

Hair washing

Overhead work

or carrying the arm in prolonged:

Abduction.

Weakness and Dexterity

Some patients report reduced:

Grip strength

or

Hand dexterity

even when obvious muscle atrophy is:

Absent.

Additional Pain

Associated discomfort may occur in the:

Head

Neck

Chest

Shoulder

and

Arm.

Arterial Symptoms

Arterial compression is less common and may produce:

Coolness

Arm fatigue

Diffuse aching

and occasionally:

Raynaud-like symptoms.

Venous Symptoms

Venous compression may be:

Intermittent

or

Persistent.

Typical findings include:

Arm swelling

Heaviness

and varying degrees of:

Cyanosis.

Physical Examination

A complete examination should assess:

Neck

Supraclavicular region

Shoulder girdle

and both:

Upper extremities.

Posture

The affected scapula may sit:

Lower

and

More anteriorly

than the opposite side.

Clavicular Position

The clavicle may appear relatively:

Horizontal

or depressed.

Supraclavicular Examination

Palpate the:

Brachial plexus region

for:

Tenderness

or a palpable:

Mass.

Tinel Sign

Percussion over the brachial plexus may reproduce:

Distal paresthesia

often along the:

Ulnar side of the hand.

Shoulder Examination

Evaluate for:

Glenohumeral instability

Rotator cuff disease

and

Scapular dyskinesis

because these can mimic or contribute to:

Thoracic outlet symptoms.

Neurologic Examination

Perform a bilateral examination of:

Motor strength

Sensation

and

Reflexes.

Intrinsic Hand Strength

Assess:

Finger abduction

Finger adduction

Grip strength

and other intrinsic:

Hand-muscle functions.

Vascular Examination

Document:

Radial pulses

Skin temperature

Color

and

Arm swelling.

Provocative Maneuvers

Several stress tests have historically been used to provoke symptoms.

These tests should be interpreted:

Cautiously.

Important Limitation

Loss of the radial pulse alone during arm positioning is:

Not diagnostic.

Pulse reduction can occur in many:

Asymptomatic individuals.

A maneuver is more meaningful when it reproduces the patient’s:

Typical symptoms.

Adson Maneuver

The Adson maneuver is performed with the arm near the:

Side

while the neck is:

Extended

and the head turned toward the:

Affected side.

Wright Maneuver

The Wright maneuver places the shoulder in:

Abduction

and

External rotation.

The patient may also be asked to take a:

Deep breath.

Elbow Position

Keeping the elbow extended during provocative testing may reduce confounding from:

Ulnar nerve compression at the elbow.

Additional Provocative Testing

Other commonly used maneuvers may include:

Elevated arm stress testing

and

Costoclavicular positioning.

No single test has sufficiently high sensitivity and specificity to establish the diagnosis by itself.

Imaging

Cervical Spine Radiographs

AP and lateral radiographs of the cervical spine may identify:

Cervical ribs

Elongated transverse processes

and

Degenerative cervical disease.

Chest Radiograph

A chest radiograph may help identify:

Cervical rib anatomy

and important alternative diagnoses such as:

Apical lung tumor.

This is particularly relevant in patients with:

Smoking history

or unexplained:

Constitutional symptoms.

MRI

MRI is useful when there is concern for:

Cervical disc disease

or another structural lesion causing:

Neural compression.

Electrodiagnostic Studies

Electrodiagnostic testing may help evaluate for:

Carpal tunnel syndrome

Cubital tunnel syndrome

Cervical radiculopathy

or other:

Peripheral neuropathies.

Role in Neurogenic TOS

Electrodiagnostic studies may be normal in many patients with:

Nonspecific neurogenic symptoms.

They are most useful when an objective neuropathy or alternative diagnosis is:

Suspected.

Vascular Studies

When arterial or venous TOS is suspected, evaluation may include:

Duplex ultrasonography

CT angiography

MR angiography

or other:

Vascular imaging.

Pathological Findings

Thoracic outlet syndrome involves compression of:

Neural

or

Vascular structures

as they pass through the:

Scalene triangle

Costoclavicular space

or

Subcoracoid/pectoralis minor region.

Common Sites of Compression

Important anatomical compression zones include the:

Interscalene triangle

Costoclavicular space

and

Pectoralis minor space.

Differential Diagnosis

The differential diagnosis is broad.

Cervical Spine Disorders

Important cervical causes include:

Cervical spondylosis

Disc herniation

and

Cervical radiculopathy.

Brachial Plexus Lesions

Tumors or other masses involving the:

Brachial plexus

or

Apex of the lung

may produce similar symptoms.

Trauma

Previous trauma involving the:

Neck

Clavicle

First rib

or

Shoulder girdle

may cause chronic pain or neurologic symptoms that resemble:

TOS.

Peripheral Nerve Entrapment

Important alternatives include:

Carpal tunnel syndrome

Cubital tunnel syndrome

Radial nerve compression

and

Suprascapular nerve compression.

Systemic Neuropathy

Neuropathies related to:

Diabetes

Alcohol use

Vitamin deficiency

or

Heavy-metal toxicity

may mimic thoracic outlet syndrome.

Complex Regional Pain Syndrome

Complex regional pain syndrome may cause:

Pain

Swelling

Color change

and

Autonomic abnormalities.

Arterial Differential Diagnosis

Potential arterial disorders include:

Atherosclerotic disease

Aneurysm

Arterial occlusion

Embolism

Raynaud disease

and

Vasculitis.

Venous Differential Diagnosis

Venous alternatives include:

Upper-extremity deep venous thrombosis

Effort thrombosis

and

Thrombophlebitis.

Treatment

Initial management is generally:

Nonoperative

for patients with uncomplicated neurogenic:

Thoracic outlet syndrome.

General Measures

Treatment focuses on:

Postural correction

Muscle strengthening

Activity modification

and elimination of:

Contributing mechanical factors.

Patient Education

Explaining the mechanical basis of symptoms can help patients understand why:

Posture

Work position

and

Repetitive overhead activity

may aggravate the condition.

Occupational Modification

Activities involving prolonged:

Arm elevation

or repetitive shoulder-girdle loading should be modified when possible.

Weight Management

When obesity contributes to postural or mechanical loading, appropriate:

Weight reduction

may improve symptoms.

Physical and Occupational Therapy

A structured rehabilitation program is the cornerstone of treatment for:

Neurogenic TOS.

Postural Reeducation

Therapy should emphasize:

Scapular positioning

Thoracic posture

and avoidance of chronic:

Shoulder depression or protraction.

Muscle Strengthening

Important muscles include:

Trapezius

Rhomboids

Levator scapulae

and other:

Scapular stabilizers.

Resistance Exercises

Strengthening may be performed using:

Elastic bands

or

Light free weights

with the shoulder generally maintained below approximately:

90° of elevation

during early rehabilitation.

Pectoral and Scalene Flexibility

Stretching may address tight:

Pectoralis minor

Scalene

and other anterior shoulder-girdle:

Soft tissues.

Time to Improvement

Symptomatic improvement may require approximately:

Several weeks to 2 months

or longer.

Long-Term Exercise

Exercises should be continued until:

Posture improves

Scapular control is restored

and weakness or deconditioning has been:

Corrected.

Medication

Medication plays a secondary role.

Treatment may include:

NSAIDs

Acetaminophen

or selected medications for:

Neuropathic pain.

Vascular Thoracic Outlet Syndrome

Patients with arterial or venous TOS require:

Specialist vascular evaluation.

Treatment may differ substantially from management of:

Neurogenic TOS.

Venous Thrombosis

Acute venous thrombosis may require:

Anticoagulation

Thrombolysis

and eventual:

Thoracic outlet decompression

depending on severity and timing.

Arterial Disease

Arterial TOS with aneurysm, thrombosis, or embolization may require:

Arterial reconstruction

in addition to:

Surgical decompression.

Surgery

Surgery is considered when:

A carefully supervised conservative program fails

and symptoms remain sufficiently severe to cause:

Major functional limitation.

Surgical Decision-Making

Patients should understand that outcomes are variable and that surgery is generally reserved for those with:

Persistent significant symptoms

or objective:

Neurovascular compromise.

Common Surgical Procedures

Typical operations include:

First-rib resection

Scalenectomy

or a combination of:

Both.

Fibrous Band Release

Congenital or acquired:

Fibrous bands

may also be divided when they contribute to:

Compression.

Vascular Reconstruction

Patients with arterial or venous injury may additionally require:

Vessel repair

Patch angioplasty

Thrombectomy

or

Grafting.

Follow-Up

Patients undergoing nonoperative treatment should be followed for:

Postural improvement

Strength

Symptom reduction

and tolerance of:

Work or activity.

Postoperative Follow-Up

After surgery, monitoring should assess:

Neurologic function

Vascular status

Wound healing

and recurrence of:

Symptoms.

Prognosis

Most patients with uncomplicated neurogenic TOS improve with:

Nonoperative management.

Surgical Prognosis

With appropriate patient selection, many patients undergoing surgery experience:

Symptomatic improvement.

Results are generally more predictable when there is a clearly defined:

Anatomic or vascular lesion.

Complications

Potential surgical complications include:

Pneumothorax

Infection

Vascular injury

Brachial plexus injury

and

Shoulder-girdle dysfunction.

Pneumothorax

Pleural injury during first-rib resection may produce:

Pneumothorax.

Vascular Injury

The proximity of the:

Subclavian vessels

creates a risk of significant:

Hemorrhage.

Brachial Plexus Injury

Manipulation or traction may result in:

Neurologic injury

with postoperative:

Pain

Weakness

or

Sensory loss.

Recurrence

Symptoms may recur after surgery because of:

Scar formation

Persistent muscle weakness

Scapular depression

or

Incomplete decompression.

Patient Monitoring

Long-term monitoring should focus on:

Pain

Paresthesia

Hand strength

Arm swelling

Vascular symptoms

and progression through:

Physical therapy.

Key Principle

Thoracic outlet syndrome is a clinical disorder caused by compression of the brachial plexus or subclavian vessels as they pass from the neck into the upper extremity.

The disorder may be:

Neurogenic, venous, or arterial, with neurogenic disease being the most common.

Diagnosis is primarily:

Clinical, and provocative maneuvers should be interpreted cautiously because pulse changes alone are not:

Diagnostic.

The differential diagnosis includes:

Cervical radiculopathy, carpal and cubital tunnel syndromes, systemic neuropathy, brachial plexus lesions, and vascular disease.

Initial management of uncomplicated neurogenic TOS centers on:

Postural correction, scapular strengthening, activity modification, and occupational rehabilitation.

Surgery, typically involving:

First-rib resection and/or scalenectomy, is reserved for selected patients with persistent disabling symptoms or significant vascular or neurologic compromise.