Orthopaedic Surgery - Thoracic Disc Herniation

Basics

Thoracic disc herniation is protrusion or extrusion of an intervertebral disc within the:

Thoracic spine

that may compress the:

Spinal cord

or

Thoracic nerve roots.

The condition can be difficult to diagnose because symptoms are often:

Nonspecific

and may resemble disorders involving the:

Chest

Abdomen

Spine

or

Peripheral nervous system.

Incidental Disc Abnormalities

A major diagnostic challenge is the high prevalence of:

Asymptomatic thoracic disc abnormalities.

Disc degeneration or herniation on imaging does not necessarily indicate that the abnormality is responsible for the patient’s:

Symptoms.

Clinical findings must therefore correlate carefully with the:

Anatomic level

and degree of:

Neural compression.

Epidemiology

Symptomatic thoracic disc disease most commonly presents during approximately the:

Fifth decade of life.

Sex

A slight predominance in:

Males

has been reported historically.

Trauma

Up to approximately:

50% of symptomatic patients

report some preceding:

Traumatic event

before symptoms begin.

Incidence

Symptomatic thoracic disc herniation is uncommon, with an estimated incidence of approximately:

1 per 100,000 persons per year.

Prevalence on MRI

Thoracic disc abnormalities are much more common than clinically symptomatic disease.

MRI studies have reported abnormalities in up to approximately:

73% of individuals.

Asymptomatic Herniation

Approximately:

37%

of individuals in some imaging series have demonstrated:

Asymptomatic thoracic disc herniation.

Genetics

There is no recognized specific:

Genetic association

with thoracic disc herniation.

Pathophysiology

Symptoms develop when the herniated disc compresses the:

Spinal cord

or

Thoracic nerve root.

Spinal Cord Compression

Because the thoracic spinal canal contains the:

Spinal cord

rather than the cauda equina, central disc herniation may produce:

Myelopathy.

Thoracic Myelopathy

Thoracic cord compression may cause:

Lower-extremity weakness

Spasticity

Hyperreflexia

Sensory disturbance

Gait dysfunction

and

Bowel or bladder abnormalities.

Unlike cervical myelopathy, upper-extremity findings are generally:

Absent.

Radiculopathy

A lateral or foraminal herniation may compress a:

Thoracic nerve root

and produce band-like pain along the:

Chest wall

or

Abdominal wall.

Associated Conditions

Thoracic disc herniation may occasionally occur in adolescents with:

Scheuermann disease.

Diagnosis

Diagnosis requires careful assessment because of the broad:

Differential diagnosis

and the high frequency of incidental:

Thoracic MRI abnormalities.

Signs and Symptoms

Patients may present with:

Axial thoracic pain

Radicular pain

or

Myelopathy.

Axial Pain

Pain may be localized to the:

Mid-thoracic

or

Lower thoracic spine.

It can be:

Aching

Deep

or

Mechanical.

Radicular Pain

Thoracic radiculopathy often produces:

Band-like pain

around the trunk.

The:

T10 dermatome

is a commonly reported symptomatic distribution.

Bowel and Bladder Dysfunction

Bowel or bladder dysfunction has historically been reported in up to approximately:

20% of symptomatic patients.

These findings suggest significant:

Spinal cord involvement.

Clinical Patterns

Two broad clinical presentations are often described.

Younger Patients

Patients younger than approximately:

40 years

more commonly have:

Soft disc herniations.

Acute Soft Disc Herniation

These cases may follow:

Trauma

and may produce relatively acute:

Cord compression

or

Radiculopathy.

They often respond favorably to appropriately selected:

Nonoperative or operative treatment.

Older Patients

Patients older than approximately:

40 years

more commonly have:

Degenerative

or

Calcified disc herniations.

Chronic Calcified Herniation

These patients may have:

Longstanding symptoms

without a clear history of trauma.

Compression of the cord or nerve root tends to be more:

Chronic.

Physical Examination

A complete neurologic examination should be performed with careful assessment for:

Myelopathy.

Gait

Observe for:

Spastic gait

Balance disturbance

Shortened stride

or difficulty with:

Tandem walking.

Motor Examination

Assess lower-extremity:

Strength

and look for signs of:

Upper motor neuron dysfunction.

Reflexes

Evaluate:

Patellar reflexes

Achilles reflexes

and look for:

Hyperreflexia

Clonus

or abnormal:

Plantar responses.

Sensory Level

A sensory level may help localize the lesion.

Useful landmarks include:

T4 – nipple line

T7 – xiphoid process

T10 – umbilicus

and

T12 – inguinal crease.

Abdominal Muscle Examination

Asymmetric contraction of the:

Rectus abdominis

during a sit-up may suggest segmental:

Thoracic neurologic dysfunction.

Superficial Reflexes

The examination may include:

Superficial abdominal reflexes

and, when appropriate,

Cremasteric reflexes.

Range of Motion

Thoracic and lumbar:

Range of motion

should be assessed, although abnormalities are usually:

Nonspecific.

Laboratory Tests

Routine laboratory tests are not required for straightforward:

Disc herniation.

Infection or Malignancy

If infection or tumor is part of the differential diagnosis, testing may include:

Complete blood count

ESR

and

C-reactive protein.

Imaging

Plain Radiographs

AP and lateral thoracic spine radiographs may demonstrate:

Degenerative changes

Disc-space narrowing

Calcification

Deformity

or

Spondylolisthesis.

Excluding Other Disorders

Radiographs may also identify:

Fracture

Tumor

Infection

or other structural abnormalities.

Level Localization

Precise localization of the involved vertebral level is essential.

Imaging should include adequate landmarks to permit reliable:

Vertebral counting.

Historically, radiographs were obtained to include the:

First rib

Twelfth rib

and

Sacrum

when possible.

MRI

MRI is the preferred imaging study for suspected:

Thoracic disc herniation.

MRI Sequences

Evaluation should include:

Sagittal

and

Axial

T1- and T2-weighted sequences.

MRI Findings

MRI can demonstrate:

Disc morphology

Spinal cord compression

Nerve-root compression

and possible:

Cord signal abnormality.

Correct-Level Confirmation

Because wrong-level surgery is a major concern in the thoracic spine, the abnormal disc level must be:

Confirmed carefully.

A sagittal localizer may be used to count:

Downward from C2

and

Upward from the sacrum.

Correlation with:

Plain radiographs

or

CT

is useful.

CT

CT is particularly useful for identifying:

Calcification

and defining:

Bony anatomy.

CT Myelography

CT myelography can demonstrate:

Neural compression

and may be used when MRI is:

Contraindicated

or limited by:

Artifact.

Limitations of CT Myelography

Because it requires:

Intrathecal contrast injection

CT myelography is invasive.

Potential complications include:

Post-dural puncture headache.

Discography

Discography has historically been used to investigate:

Axial thoracic pain

when multiple disc levels are abnormal or severe pain persists despite relatively limited:

Imaging findings.

Its diagnostic value remains:

Controversial.

Differential Diagnosis

The differential diagnosis is extensive.

Intrathoracic Causes

Potential causes include:

Pulmonary

Pleural

or other:

Thoracic abnormalities.

Intra-Abdominal Causes

Abdominal pathology can occasionally mimic:

Thoracic radicular pain.

Infectious Causes

Important possibilities include:

Discitis

Vertebral osteomyelitis

and

Epidural abscess.

Neoplastic Causes

Primary or metastatic tumors may cause:

Thoracic pain

Radiculopathy

or

Myelopathy.

Degenerative Causes

Other spinal causes include:

Facet arthropathy

Thoracic stenosis

and other forms of:

Degenerative spondylosis.

Metabolic and Deformity Causes

Consider:

Metabolic bone disease

Compression fracture

and spinal:

Deformity.

Neurogenic Causes

Neurologic alternatives include:

Peripheral neuropathy

Herpes zoster

Spinal cord tumor

and other causes of:

Thoracic neuralgia or myelopathy.

Treatment

Treatment depends primarily on the presence or absence of:

Neurologic compromise.

General Measures

Acute thoracic disc herniation without significant neurologic deficit can often be treated initially:

Nonoperatively.

Natural History

Soft acute thoracic disc herniations may behave similarly to:

Lumbar disc herniations

and may improve with:

Time

and

Conservative management.

Activity

Activity may continue:

As tolerated

provided there is no associated:

Fracture

Gross instability

or other structural contraindication.

Relative Rest

Short-term reduction of provoking activities may help control:

Acute pain.

Prolonged bed rest is generally avoided.

Physical Therapy

Physical therapy may be useful for:

Pain control

Mobility

Flexibility

and

Strengthening.

Acute Phase

Passive modalities may include:

Heat

Ice

and selected therapeutic:

Modalities.

Rehabilitation Phase

As symptoms improve, treatment may progress to:

Range-of-motion exercises

Flexibility exercises

and

Strengthening.

Extension Exercises

Some programs include:

Thoracic extension exercises.

These should be individualized and discontinued if they increase:

Radicular pain

or

Myelopathic symptoms.

Medication

First-Line Treatment

Medication may include:

Acetaminophen

or

NSAIDs

when medically appropriate.

NSAIDs

Anti-inflammatory medication may help reduce:

Pain

provided the patient does not have important:

Gastrointestinal

Renal

or other contraindications.

Aspirin

Enteric-coated aspirin has historically been used for:

Pain and inflammation

although other NSAIDs are now more commonly selected.

Chronic Opioids

There is no routine role for:

Long-term maintenance opioid therapy

in uncomplicated thoracic disc disease.

COX-2 Inhibitors

Selected patients may receive:

COX-2 selective anti-inflammatory medication

after considering:

Cardiovascular

Renal

and

Gastrointestinal risks.

Injections

Selected patients with persistent radicular pain may benefit from:

Thoracic epidural steroid injection

or

Intercostal injection.

These treatments may reduce pain but do not correct:

Mechanical spinal cord compression.

Surgery

Surgery is indicated when:

Neurologic compromise progresses

or nonoperative management fails to provide an acceptable:

Quality of life.

Major Surgical Indications

Common indications include:

Progressive myelopathy

Significant motor deficit

Severe spinal cord compression

or persistent disabling:

Pain.

Preoperative Assessment

Because thoracic surgical approaches may involve the chest and carry substantial physiologic stress, selected patients may require preoperative evaluation by:

Internal medicine

Cardiology

or

Anesthesiology.

Surgical Level Confirmation

Intraoperative imaging should be used to verify the:

Correct vertebral level

before disc removal.

Anterior Transthoracic Approach

The:

Anterior transthoracic approach

has traditionally been used for many central thoracic disc herniations because it permits direct access to the:

Anterior spinal canal.

Posterior Approaches

Direct posterior laminectomy alone is generally:

Not recommended

for central thoracic disc removal because manipulation of the spinal cord carries a high risk of:

Neurologic injury.

Pediculofacetectomy

A posterior:

Transpedicular or pediculofacetectomy approach

may be appropriate for selected:

Lateral lesions.

Lateral Approaches

Other options include:

Costotransversectomy

and

Lateral extracavitary approaches.

Thoracoscopic Surgery

Video-assisted thoracoscopic surgery provides a:

Minimally invasive anterior approach

for selected patients.

Fusion

Whether spinal fusion is required remains dependent on:

Extent of bone removal

Pre-existing deformity

and resultant:

Stability.

Rib-Cage Stability

The thoracic spine has inherent stability from the:

Rib cage.

However, substantial resection of:

Facets

Pedicles

or vertebral body structures may produce:

Iatrogenic instability.

Follow-Up

Follow-up should assess:

Pain

Neurologic status

and progression of:

Recovery.

Historical Follow-Up Schedule

A traditional postoperative schedule may include visits at approximately:

6 weeks

3 months

6 months

1 year

and

2 years

with subsequent long-term review as indicated.

Referral

Patients may require evaluation by other specialists when alternative diagnoses remain possible, including:

Thoracic surgeons

General surgeons

Rheumatologists

or other relevant:

Specialists.

Prognosis

Most appropriately selected patients undergoing thoracic disc excision achieve:

Good or excellent long-term outcomes.

Prognostic Factors

Recovery depends on:

Duration of symptoms

Severity of myelopathy

Extent of spinal cord compression

Disc calcification

and

Preoperative neurologic status.

Acute Soft Disc Prognosis

Younger patients with:

Soft acute herniations

and shorter symptom duration generally have greater potential for:

Neurologic recovery.

Chronic Calcified Disc Prognosis

Longstanding compression from:

Calcified disc material

may produce irreversible:

Spinal cord injury.

Complications

Surgical Complication Rate

Historical series have reported an overall complication rate of approximately:

14–15%

after thoracic disc excision.

Neurologic Injury

The most serious complication is:

Spinal cord injury

with:

Paraparesis

or

Paralysis.

Dural Injury

Possible complications include:

Dural tear

and

Cerebrospinal fluid leak.

Pulmonary Complications

Anterior thoracic approaches may be associated with:

Pneumothorax

Hemothorax

Pleural effusion

or other:

Pulmonary problems.

Infection

Potential infectious complications include:

Wound infection

and deeper:

Spinal infection.

Instability and Deformity

Extensive surgical resection may lead to:

Segmental instability

or

Postoperative kyphosis.

Nonoperative Neurologic Progression

Patients treated nonoperatively must be monitored for progression of:

Myelopathy

or other:

Neurologic compromise.

Patient Monitoring

Monitoring should include assessment of:

Pain

Gait

Motor function

Sensation

and

Bowel and bladder function.

After Fusion

If arthrodesis is performed, follow-up should also evaluate:

Fusion maturation

and

Spinal alignment.

Red-Flag Findings

Urgent reassessment is warranted for:

Progressive leg weakness

Increasing gait difficulty

New sensory level

Worsening spasticity

or

New bowel or bladder dysfunction.

Key Principle

Thoracic disc herniation is an uncommon symptomatic disorder despite the frequent finding of incidental thoracic disc abnormalities on MRI.

Clinical presentation may consist of:

Axial thoracic pain, radiculopathy, or spinal cord compression with myelopathy.

MRI is the preferred imaging study for assessing:

Neural compression, while CT is particularly valuable for evaluating:

Calcified disc material and bony anatomy.

Patients without significant neurologic compromise may initially be treated with:

Activity modification, analgesia, and physical therapy.

Surgery is reserved for:

Progressive myelopathy, substantial neurologic deficit, severe cord compression, or persistent disabling symptoms despite appropriate nonoperative care.

Simple posterior laminectomy for central disc excision is generally avoided because of the risk of:

Spinal cord injury.