Cervical Disc Protrusion and Lesions

The intervertebral discs lie between adjacent vertebrae. They consist of a peripheral fibrocartilagenous part called the annulus fibrosus and a central semifluid/gelatinous part, the nucleus pulposus.

• There is no disc between C1 and C2 (atlas and axis), and only ligaments and joint capsules limit excessive motion.¹
• Disc degeneration or herniation can injure the spinal cord or nerve roots.¹
• Cervical radiculopathy is compression or injury to a nerve root in the cervical spine.² Its most common causes are cervical disc herniation and degenerative disease.²
• The term myelopathy is used to describe any neurological deficit related to the spinal cord itself. Myelopathy may be due to compression of the spinal cord by a prolapsed cervical disc.
• There are separate articles entitled Spinal Cord Injury and Acute Spinal Cord Compression.

Cervical disc disorders can include:

Disc herniation (prolapsed intervertebral disc)

• The nucleus pulposus bulges or breaks through the annulus of the disc.
• It may occur from a single whiplash injury but repetitive injuries are more common.
• Cervical disc herniation occurs most frequently at the levels of C4/5, C5/6, and C6/7.
• Posterior herniation causes symptoms by compressing the cord or a nerve root, or by stretching the posterior longitudinal ligament or posterior annulus.

Degenerative disc disease (cervical spondylosis)

• The exact cause of this is not known. Some suggest that it is a natural part of ageing, however, disc degeneration can also occur in young people. The cause is likely to be multifactorial including genetic, environmental, traumatic, inflammatory, infectious and other factors.³
• Annular tears, internal disc disruption and resorption, disc space narrowing, disc fibrosis and osteophyte formation can all occur.³
• Degenerative disc disease may lead to disc herniation.
• There is a separate article entitled Cervical Spondylosis.

Internal disc disruption¹

• This includes damage to the disc without external deformity.
• It may result from whiplash or other trauma to the neck.
• Degenerative disc disease can progress to internal disc disruption.
• There is a separate article entitled Whiplash and Cervical Spine Injury.

Infection (discitis)

• This is discussed in the separate article Spinal Disc Disorders.

During assessment of a patient with neck pain, always be alert to red flag symptoms or signs.

History¹

• If there was an injury, note the time since the injury and mechanism.
• Ask about the pain:
  • Note the distribution. Neck pain can radiate to an upper limb. Pain is usually unilateral, but may be bilateral. Pain can disturb sleep. Neck pain is frequently absent in radiculopathy.
  • Ask about speed of onset. Insidious onset of symptoms is usual in cervical radiculopathy but it may be abrupt if acute injury.
  • Pain from the disc without nerve root involvement, is typically vague, diffuse, and distributed axially.
  • Activities that raise pressure in the disc such as lifting or a Valsalva manoeuvre will exacerbate symptoms. Lying down decreases pressure in the disc and eases pain.
  • Driving causes vibration that aggravates disc pain.
• Make a systematic enquiry about general health. Fever suggests infection. Unintentional weight loss suggests malignancy.

Examination¹

• If pain originates from the disc but there is no nerve root involvement, there will be normal neurological examination.
• Tenderness with movement in the posteroanterior plane may suggest disc pathology.
• Signs of radiculopathy on examination:
  • The neck will show a decreased range of movement. This is very common with pain and spasm from any cause.
  • Extension and rotation increase pain. The Spurling manoeuvre is when the patient's neck is extended, bent laterally, and held down. It elicits radicular symptoms.
  • The abduction sign is when pain improves when the neck is flexed or on abduction of the affected arm over the top of the head.
  • Upper limb weakness, paraesthesia, dermatomal sensory deficit and changes to reflexes can occur as outlined in the table below.²
  • A herniated disc can also produce thermal changes (thermatomes) in specific distributions.

  Neurological features associated with cervical radiculopathy
  Nerve root	Muscle weakness	Reflex changes	Sensory changes
  C5	Shoulder abduction and flexion Elbow flexion	Biceps	Lateral arm
  C6	Elbow flexion Wrist extension	Biceps Supinator	Lateral forearm Thumb Index finger
  C7	Elbow extension Wrist flexion Finger extension	Triceps	Middle finger
  C8	Finger flexion	None	Medial side lower forearm Ring and little fingers
  T1	Finger abduction and adduction	None	Medial side upper forearm Lower arm

• Signs of myelopathy on examination:
  • Increased upper and lower limb reflexes or other upper motor neurone signs suggest myelopathy.
  • Upper motor neurone signs include:
    • Weakness
    • Spasticity
    • Hyperreflexia
    • Positive Babinski sign (upgoing plantars)
    • Clonus
    • Positive Hoffman's reflex (flicking a finger causes adjacent fingers to flex)
  • Sphincter disturbances are late features of cervical and thoracic cord compression.
  • Cervical spine lesions can produce quadriplegia.
  • Urgent evaluation and action is needed.

• It is easy to diagnose that pain originates from the neck but being sure that there is a disc lesion usually requires imaging studies.
• Neck pain in the general population is very common.⁷ Most will not be a disc lesion.
• Differential diagnoses include:
  • Degenerative disc disease/cervical spondylosis
  • Traumatic prolapsed intervertebral disc
  • Simple neck pain; acute neck strain, postural neck ache or whiplash
  • Headache
  • Referred pain, e.g. from shoulder
  • Malignancy: primary tumours, secondary deposits or myeloma
  • Infections: discitis, osteomyelitis or tuberculosis
  • Fibromyalgia
  • Vascular insufficiency
  • Psychogenic neck pain
  • Inflammatory disease: rheumatoid arthritis
  • Metabolic diseases: Paget's disease, osteoporosis

• Blood tests may be guided by suggestions of other rheumatological pathology.
  • Full blood count may show anaemia of chronic disease or evidence of infection.
  • Elevated ESR is nonspecific but suggests an inflammatory process.
  • Rheumatoid factor should be requested if rheumatoid arthritis is considered and HLA-B27 may indicate ankylosing spondylitis.
• Imaging studies are important but they should be interpreted in the light of the clinical picture as positive findings are quite common in people without any complaints.⁸ People with abnormal X-rays are more likely to develop symptoms⁹ but this is not an indication for treatment in anticipation.
  • Plain X-ray of the cervical spine may be used to evaluate chronic degenerative changes, metastatic disease, infection, spinal deformity, and stability. Interpretation is difficult because degenerative features are almost universal over the age of 35 years.
  • MRI scans are best at showing soft tissue lesions such as discs.
  • CT and CT myelography are less often used.
• The integrity of nerves may be assessed by nerve conduction studies (electromyography).

• Look for and treat any comorbidity.
• Drug treatment:
  • Analgesia may relieve pain and help muscle spasm.
  • If pain is chronic and severe, analgesia may be enhanced by the addition of amitriptyline or gabapentin.
  • Diazepam for 3–7 days may be useful for people with severe muscle spasm.
• Early mobilisation is important.
• Physiotherapy including stabilisation exercises and posture training may be valuable.
• Heat and massage may relieve muscle spasm.
• Neck supports should be used for as short a time as possible, i.e. 2–4 days, and under supervision.
• There is insufficient evidence to recommend manual therapies such as manipulation.
• Surgery:
  • The finding of a disc lesion does not mean that surgery is indicated and in most cases conservative management is all that is needed. There may even be spontaneous regression of a herniated disc.¹⁰
  • If there are significant neurological abnormalities such as UMN signs in the limbs or bladder disturbance, surgical decompression is indicated.
  • Surgery may also be indicated in intractable pain.

• If an intervertebral disc compresses the spinal cord, it can produce myelopathy with weakness, hyperreflexia, and neurogenic bowel and bladder dysfunction. There may be associated significant upper limb weakness or numbness as well as pain.¹
• Beware of missing serious underlying disease including malignancy, infections producing abscesses and inflammatory conditions. Always be alert to red flags.

• The prognosis for cervical radiculopathy is favourable: symptoms resolve in most people without surgical treatment.^11,12
• Surgery also has good results but is indicated in only a minority. It is likely that the attitude of the patient to active rehabilitation is very important for a good result. However, the general prognosis for neck pain is not good and it is often chronic and persistent.