Orthopaedic Surgery - Cervical Disc Herniation

Basics

Cervical disc herniation occurs when intervertebral disc material displaces posteriorly into the spinal canal or neural foramen, resulting in compression of a cervical nerve root, the spinal cord, or both.

Mechanical compression is accompanied by an inflammatory response and may produce neck pain, cervical radiculopathy, cervical myelopathy, or a combination of these findings.

Classification

Cervical disc herniations may be classified according to clinical onset, anatomic location, or the morphology of the displaced disc material.

Clinically, the condition may present acutely or develop gradually.

Anatomically, the herniation may be central, paracentral, foraminal, or lateral depending on its location within the spinal canal.

Classification by Disc Morphology

Disc displacement can also be described as a bulge, protrusion, extrusion, or sequestration.

A protrusion remains broadly connected with the parent disc, whereas an extrusion represents greater displacement of disc material through the annulus.

A sequestrated fragment has completely separated from the parent disc.

Classification of Myelopathy

Several classification systems are available for cervical myelopathy.

These systems generally assess factors such as gait, pain, upper- and lower-extremity weakness, upper and lower motor neuron findings, bladder function, and fine motor ability.

The purpose is to quantify severity and monitor neurologic progression or response to treatment.

Epidemiology

Cervical disc herniation occurs most commonly in adults older than 30 years, with an average age near 50 years.

Cervical radiculopathy is considerably more common than cervical myelopathy, and radiculopathy only rarely progresses to spinal cord dysfunction.

Incidence

The reported annual age-adjusted incidence of cervical radiculopathy is approximately 107.3 per 100,000 men and 64.5 per 100,000 women.

The incidence is particularly high in adults aged 50–54 years, reaching approximately 203 per 100,000 people per year.

Prevalence of Neck Pain

Neck pain is extremely common.

As many as two-thirds of adults experience at least one significant episode of neck pain during their lifetime.

Not all neck pain, however, is caused by cervical disc herniation.

Risk Factors

Risk factors include repetitive lifting, cigarette smoking, and prolonged or repetitive overhead work.

These activities may increase mechanical stress on the cervical spine or accelerate degenerative disc changes.

Pathophysiology

The mechanical component of cervical nerve compression is well established.

However, symptoms are not produced by compression alone.

Mechanical, ischemic, and inflammatory mechanisms all contribute to nerve-root and spinal-cord dysfunction.

Inflammatory Mediators

Chemical mediators released around the compressed nerve root can contribute to pain and irritation.

These include substance P, interleukin-1, interleukin-6, bradykinin, tumor necrosis factor-alpha, and prostaglandins.

This inflammatory response helps explain why symptoms may be severe even when radiographic compression appears relatively modest.

Etiology

Cervical disc herniations may occur following trauma or may develop without a specific traumatic event as part of degenerative disc disease.

Age-related degeneration weakens the annulus fibrosus and allows nucleus pulposus material to migrate posteriorly.

Associated Conditions

Cervical disc herniation may coexist with congenital cervical spinal stenosis, ossification of the posterior longitudinal ligament, and cervical spondylosis.

These abnormalities reduce the available space for the spinal cord and nerve roots and may increase the clinical significance of even relatively small disc protrusions.

Diagnosis

Signs and Symptoms

Symptoms may begin suddenly or develop gradually.

The clinical spectrum includes neck pain, occipital pain, shoulder-girdle discomfort, arm pain, paresthesias, sensory loss, and weakness.

Symptoms are often aggravated by particular positions or movements of the neck.

Cervical Radiculopathy

Compression of an individual cervical nerve root may produce a characteristic combination of motor weakness, sensory disturbance, pain, and reflex changes.

Although classic dermatomal and myotomal patterns are useful, actual symptoms may overlap and do not always follow a perfectly defined distribution.

Spurling Test

The Spurling maneuver can reproduce radicular symptoms.

The patient’s neck is extended, rotated, and laterally bent toward the symptomatic side, followed by gentle axial compression.

Reproduction of radiating pain or paresthesias into the ipsilateral arm supports cervical nerve-root irritation.

Cervical Myelopathy

Cervical myelopathy usually develops insidiously and may follow a gradual, stepwise pattern of neurologic decline.

Only a small proportion of patients experience rapid deterioration.

Because spinal cord dysfunction can become irreversible, early recognition is important.

Symptoms of Myelopathy

Typical symptoms include progressive gait disturbance, imbalance, falls, deterioration in hand dexterity, generalized weakness, and difficulty with fine motor tasks.

Patients may describe their legs as stiff or “jumpy” and may notice increasing difficulty with buttons, handwriting, or handling small objects.

Advanced Myelopathic Symptoms

More advanced spinal cord dysfunction can produce bowel, bladder, or sexual dysfunction.

These symptoms warrant prompt neurologic and surgical evaluation.

History

Patients should be questioned about the onset, duration, distribution, and progression of pain, paresthesias, numbness, and weakness.

The clinician should also specifically ask about balance problems, falls, gait changes, loss of hand dexterity, and bowel or bladder symptoms.

Sensory Symptoms

Sensory abnormalities do not always follow a precise dermatome.

Overlap between adjacent cervical nerve roots is common, and symptoms may be modified by coexisting peripheral nerve compression.

Physical Examination

The cervical spine should be assessed for range of motion, tenderness, and reproduction of symptoms with movement.

A complete neurologic examination of the upper and lower extremities should include motor testing, sensory testing, reflexes, gait assessment, and examination for long-tract signs.

Motor Examination

Muscle strength should be tested systematically to identify weakness corresponding to a particular cervical nerve root.

Weakness may involve the shoulder, elbow, wrist, or hand depending on the level of compression.

Reflex Examination

Important reflexes include:

C5 – biceps reflex

C6 – brachioradialis reflex

C7 – triceps reflex

Asymmetry or reduction may support a cervical radiculopathy, whereas generalized hyperreflexia can suggest myelopathy.

Babinski Sign

The Babinski response is tested by applying a noxious stimulus along the plantar aspect of the foot.

A positive test consists of extension of the great toe, often accompanied by fanning of the lesser toes.

This suggests an upper motor neuron abnormality and may occur in cervical myelopathy.

Hoffmann Reflex

The Hoffmann reflex is elicited by flicking or pinching the distal phalanx or nail of the middle finger.

A positive response causes reflex flexion or adduction of the thumb and index finger.

When present in the appropriate clinical context, it may indicate cervical spinal cord dysfunction.

Finger Escape Sign

The finger escape sign is associated with cervical myelopathy.

The small finger gradually abducts away from the other digits when the patient attempts to keep the fingers fully extended and adducted.

This reflects weakness or dysfunction of the intrinsic hand muscles.

Electrodiagnostic Testing

Electromyography and nerve conduction studies can provide objective evidence of neurologic dysfunction.

They are particularly useful when there is concern for coexisting peripheral neuropathy, peripheral nerve entrapment, or inconsistency between the history, physical examination, and imaging findings.

Imaging

Plain Radiographs

Conventional cervical spine radiographs can demonstrate alignment, disc-space narrowing, osteophytes, and other degenerative changes.

Oblique views may help visualize the neural foramina.

Flexion-extension radiographs can be used when instability is suspected.

Limitations of Radiographs

Degenerative changes are common in asymptomatic adults, particularly after the age of 40.

Therefore, plain radiographs should be interpreted in conjunction with the clinical picture rather than assumed to identify the source of symptoms.

They are particularly useful after trauma or when symptoms have failed to improve with conservative care.

MRI

MRI is the preferred noninvasive imaging study for most patients who require advanced evaluation.

It provides excellent visualization of intervertebral discs, spinal cord, nerve roots, ligaments, and other soft tissues without ionizing radiation.

Indications for MRI

MRI is particularly useful in patients with persistent radicular symptoms, progressive neurologic deficit, suspected myelopathy, or failure of conservative treatment.

The imaging findings should correlate with the patient’s symptoms and physical examination.

CT Myelography

CT myelography provides detailed assessment of compression from both bone and soft tissue.

It can be useful when MRI cannot be performed or when metallic hardware significantly limits MRI quality.

Because CT myelography is invasive, it is generally reserved for selected situations.

Selective Diagnostic Injections

Selective cervical nerve-root injections may occasionally be used when multiple potential sites of compression are present and the symptomatic level is unclear.

Temporary relief following injection can help identify the primary pain generator.

Pathologic Findings

The fundamental abnormality is herniation of nucleus pulposus material through or beyond the annulus fibrosus.

Compression of a nerve root produces radiculopathy, whereas compression of the spinal cord may cause myelopathy.

Differential Diagnosis

Cervical disc herniation can mimic numerous shoulder, peripheral nerve, neurologic, infectious, or neoplastic disorders.

A careful examination is therefore necessary before attributing upper-extremity symptoms solely to the cervical spine.

Shoulder and Upper-Extremity Disorders

Intrinsic disorders of the shoulder, elbow, or wrist can produce similar symptoms.

These include degenerative arthritis, shoulder impingement, rotator cuff disease, and joint instability.

Peripheral Nerve Entrapment

Peripheral nerve compression should also be considered.

Important examples include carpal tunnel syndrome, cubital tunnel syndrome, Guyon canal syndrome, and thoracic outlet syndrome.

Neurologic Disorders

Neurologic conditions that may mimic cervical radiculopathy or myelopathy include brachial plexopathy, multiple sclerosis, amyotrophic lateral sclerosis, and tumors of the brain or spinal cord.

Infection and Malignancy

Serious alternative diagnoses include infectious discitis, vertebral osteomyelitis, and metastatic malignancy.

Systemic symptoms, severe unremitting pain, fever, weight loss, or a history of cancer should prompt further investigation.

Treatment

General Measures

Most patients with cervical radiculopathy can initially be treated nonoperatively.

Management may include activity modification, analgesic medication, anti-inflammatory therapy, short-term muscle relaxants, selective use of a soft cervical collar, and physical therapy.

Natural History

Cervical radiculopathy is frequently self-limiting.

Approximately 75% of patients improve spontaneously with nonsurgical treatment.

For this reason, conservative management is generally the initial treatment of choice when no progressive neurologic deficit or myelopathy is present.

Activity Modification

Relative rest and avoidance of activities that clearly worsen symptoms can be helpful during the acute phase.

Prolonged inactivity should be avoided because it may contribute to deconditioning and stiffness.

Soft Cervical Collar

A soft cervical collar may provide short-term symptomatic relief in acute cases by limiting painful motion.

Prolonged use is generally discouraged because it can lead to muscle weakness and dependence.

Physical Therapy

Physical therapy can address pain, mobility, strength, and return to function.

Treatment may initially include passive modalities, followed by stretching, postural work, strengthening, and progressive activity.

Cervical Traction

Cervical traction may reduce radicular symptoms in selected patients.

It can be performed under supervision in therapy or with an appropriate home device.

Its effectiveness varies among individuals.

Medication

Long-term maintenance opioid therapy has no established role in routine management of cervical disc herniation.

Medication should be directed toward short-term symptom control while the underlying condition is treated conservatively or surgically as appropriate.

First-Line Medication

Common first-line options include NSAIDs, acetaminophen, and selected anti-inflammatory agents when there are no contraindications.

Gastrointestinal, renal, cardiovascular, and other patient-specific risks should be considered.

Second-Line Treatment

Selected patients may be considered for cervical epidural corticosteroid injection.

Such injections may reduce radicular inflammation and pain, although they do not correct the structural disc herniation itself.

Indications for Surgical Referral

Surgical evaluation should be considered when symptoms fail to improve after approximately 6 weeks of appropriate conservative treatment, especially when pain remains disabling.

Earlier referral is indicated for progressive neurologic deficit, severe motor weakness, or signs of cervical myelopathy.

Surgery

Operative options include anterior cervical discectomy and fusion, posterior cervical foraminotomy, laminoplasty, and cervical disc arthroplasty.

The choice depends on the location of compression, cervical alignment, number of affected levels, patient age, and associated degenerative changes.

Anterior Cervical Discectomy and Fusion

Anterior cervical discectomy and fusion (ACDF) is a commonly used procedure for cervical radiculopathy.

It is particularly appropriate when the disc herniation is central or when there is associated kyphosis, axial neck pain, or anterior spinal cord compression.

Principles of ACDF

The affected disc is removed through an anterior approach.

The compressed nerve root or spinal cord is decompressed, after which the disc space is reconstructed and fused.

Instrumentation may be added depending on the level and pathology.

Posterior Cervical Foraminotomy

A posterior laminoforaminotomy or foraminotomy can be used for lateral or foraminal soft-disc herniations, particularly when arm pain predominates.

This approach can decompress the affected nerve root while preserving the intervertebral disc and motion segment in selected patients.

Laminoplasty

Laminoplasty is a motion-preserving posterior decompression procedure primarily used for multilevel cervical spinal cord compression in a lordotic cervical spine.

It may be an alternative to multilevel laminectomy and fusion or extensive anterior decompression in appropriately selected patients.

Cervical Disc Arthroplasty

Cervical total disc arthroplasty replaces the diseased disc with an artificial disc while preserving segmental motion.

For selected patients with single-level degenerative cervical radiculopathy, short- and intermediate-term outcomes can be comparable to those of ACDF.

Surgical Treatment of Myelopathy

The operative approach for cervical myelopathy depends on cervical alignment, number of involved levels, location of compression, previous surgery, and relevant medical conditions.

Anterior, posterior, or combined approaches may be required.

Follow-Up

Patients treated conservatively should be reassessed for improvement or progression of pain, weakness, numbness, gait disturbance, and fine-motor dysfunction.

Development of new myelopathic signs requires prompt reassessment.

Referral for Possible Shoulder Pathology

Shoulder disorders can closely mimic cervical radiculopathy.

When examination suggests intrinsic shoulder disease, referral to an orthopaedic or shoulder specialist may be appropriate.

Prognosis

The overall prognosis for cervical radiculopathy is generally favorable.

Population-based studies have shown that approximately 90% of patients can achieve satisfactory outcomes with either nonoperative or operative treatment.

Prognosis of Cervical Myelopathy

Surgery for cervical myelopathy frequently produces meaningful neurologic improvement or stabilization.

However, the degree of recovery depends heavily on the severity and duration of spinal cord compression.

Importance of Early Recognition

Early diagnosis and treatment of cervical myelopathy are important because prolonged spinal cord compression can produce irreversible neurologic injury.

Patients with moderate or severe myelopathy may continue to have residual neurologic deficits even after successful decompression.

Complications of Surgery

Potential complications include infection, persistent neurologic deficit, new neurologic deficit, worsening weakness, pseudarthrosis, adjacent-segment degeneration, dysphagia, and recurrent laryngeal nerve injury.

The complication profile varies with the surgical approach.

Surgical Infection

Posterior cervical procedures generally have a higher wound-infection risk than anterior approaches.

Careful soft-tissue handling and postoperative wound monitoring are therefore important.

C5 Palsy

A new postoperative C5 nerve-root palsy can occur after either anterior or posterior cervical decompression.

It typically produces deltoid and sometimes biceps weakness.

Many patients experience substantial functional recovery over time.

Dysphagia

Difficulty swallowing is common after anterior cervical surgery.

It usually improves gradually and often resolves within several months, although persistent symptoms may occasionally occur.

Pseudarthrosis

Failure of fusion, or pseudarthrosis, can cause persistent neck pain and may occasionally require revision surgery.

The risk is influenced by smoking, multilevel surgery, bone quality, and other patient factors.

Adjacent-Segment Degeneration

Degenerative changes may develop at levels adjacent to a cervical fusion over time.

Some degeneration reflects the natural history of cervical spondylosis, while altered biomechanics following fusion may also contribute.

Plate-Related Adjacent-Level Degeneration

Anterior plates positioned close to an adjacent disc space may contribute to accelerated degeneration or ossification at that level.

Appropriate implant positioning may reduce this risk.

Hoarseness

Hoarseness after anterior cervical surgery may result from injury or irritation of the recurrent laryngeal nerve.

Most cases improve, but persistent vocal changes can occasionally occur.

Patient Monitoring

Patients should be monitored for progressive weakness, worsening sensory loss, gait deterioration, loss of fine-motor control, bowel or bladder dysfunction, and other signs of spinal cord involvement.

Any progression of myelopathic symptoms should prompt urgent specialist evaluation.