CERVICAL DISC PROLAPSE
(Also known as Slipped disc; Disc herniation; pinched nerve)

HOW ARE THINGS SUPPOSED TO WORK?

 
The spinal cord is protected by the bones of the spine, called vertebrae
 
Between these bones are fibrous cushions called inter vertebral discs which help absorb impact and help with movement
 
Each vertebra is connected to the one above and the one below by a facet joint which allows the neck to bend forward, backward, and to rotate.
 
 The vertebrae have gaps which allow nerve roots to enter and exit the spinal cord, thus allowing transmission of information between extremities and the nervous system. We can in this way move and feel e.g. pain, touch, and temperature 

THE INTERVERTEBRAL DISC

 
Gel-like nucleus
 
Tough, fibrous annulus
 
Retaining Ligaments
 
Inter vertebral Disc


WHAT GOES WRONG?

   
 
 
 
Varying degrees of bulging discs, resulting in a complete disc prolapse
 
 
 
 
 
 
 
 
 
 
 
 
The prolapsed portion of the disc may compress on nerve roots
 
 

WHAT CAUSES IT?

Poor posture contributes to disc prolapse especially in occupations at risk e.g. computer operator, mechanics, painters…

Trauma, with sudden forward bending (flexion) of the neck, as occurs in whiplash can result in disc prolapse.

Older people are more prone to prolapse. As you get older, the nucleus degenerates and becomes less pliable and therefore less effective as a cushion. Just minor trauma can rupture the outer layer, causing prolapse. In such patients, depending on the severity of trauma, there may also be associated fractures of the spine.

Trivial trauma can also cause a disc prolapse in patients with a pre-existing condition, like cervical spondylosis.

HOW IS THE PATIENT AFFECTED?

The protruding disc can press on nerves, producing:

- weakness
- pain
- numbness
- tingling

This will affect the shoulder and arms. The doctor may see a change in the reflexes, sensation and power in the arms because of the pressure on the nerves.

Neck stiffness is frequently associated, due to spasm of the muscles around the vertebrae.

Sometimes, the disc can also press on the spinal cord if it prolapses centrally. Depending on the degree of compression, one may even develop weakness of the legs, with difficulty walking and a stiff gait.

On other occasions, a combination of spinal cord and nerve injury occurs, resulting in a variable combination of the signs and symptoms discussed above.

HOW IS IT DIAGNOSED?

On examination, the doctor will look at the location of the pain, assess muscle weakness and look at the distribution of sensory loss and abnormal reflexes in order to locate the level of disc herniation.

Tests to confirm the diagnosis include:

- X-Ray of the spine This shows bony changes e.g. a co-existing fracture following injury. Also shows instability of vertebrae from severe rupture of ligaments. Bony spurs may be seen with chronic spondylosis. These occur with age and, together with a prolapsed disc, may compromise a nerve root

- CT Scan; MRI Scan This gives a more detailed picture of spinal cord, disc, ligaments and nerves and will identify a disc protrusion

Axial & Sagittal Myleogram showing cervical disc herniation

MRI showing compression of spinal cord by herniated disc


Electrical studies
These are performed by a neurologist and may be useful to identify the nerves damaged due to compression and is also useful to exclude other conditions producing similar symptoms e.g. Carpal Tunnel Syndrome.

Discography As in the lumbar and thoracic spine, cervical discography (see figure) remains controversial. Although the discogram may add to the clinician's knowledge, it should not be used by itself to predicate treatment.

AP View
Lateral View

WHAT TREATMENT IS AVAILABLE?

Many patients will improve without treatment. These people usually have a minor bulging of the disc which doesn’t compress the nerves.

Other patients will have ongoing pain, numbness and weakness, and available treatment is non-surgical or surgical.

· NON-SURGICAL
Conservative care includes the prescription of:
o Short period of bed rest: Only 1-2 days of rest is often beneficial. Thereafter, it is important to begin movement to prevent stiffness of the joints and wasting of muscles.
o Use of Neck Collar
o Analgesics: Pain Medication may be non-prescription e.g. Panado, Aspirin, Propain, Stopayne. Most are a combination of these and a muscle relaxant. If the pain is bad, the doctor may prescribe narcotics e.g. morphine, pethidine. These are usually strictly for short term use. Sleeping tablets may also be necessary.
o Anti-inflammatories: Non-steroidal anti-inflammatory drugs (NSAIDs) e.g. Voltaren, Celebrex, Coxflam, Aspirin, are sometimes combined with other analgesics and are useful to decrease swelling and inflammation around the nerve root but one must be careful of side effects e.g. gastritis, bleeding stomach ulcers.
o Steroids: Can be given orally or injected and have a powerful anti-inflammatory effect. They have severe side effects, however, and should be carefully discussed with your doctor. Injections of steroids into the area around the spinal nerves, or into muscle spasms are used by doctors who are specially trained in this technique. Trigger point injections can also help but these won’t help to heal the disc. These locally injected steroids are not associated with systemic side effects.
o Physiotherapy: Physiotherapists may instruct you on specific exercises and can be done at home or may require a visit to the physiotherapist.
o Traction, electrical stimulation, hot & cold packs and manual therapy are often used
o Anti epileptics: Are sometimes used for nerve pain e.g. Tegretol, Trileptil, Neurontin.

Most of these decrease irritation at the nerve to relieve pain and improve the patient’s physical condition. It involves a well organized programme and collaboration of Neurologists, Orthopedic surgeons and Physiotherapists.
It is important not to overdo the medication, as it won’t necessarily cause it to heal better and may cause side effects and dependency.
You must let you doctor know of any drug allergies.

SURGICAL
Surgery may be needed for intolerable pain which has failed to respond to non-operative management mentioned above. The goal is to remove the part of the disc which is protruding onto the nerve and can be performed via the front (Anterior approach) or the back (Posterior approach) of the neck. The choice is influence by the location of the disc and the experience of the surgeon.

Because the anterior approach involves removal of the entire disc with the herniated portion, fusion of the vertebrae is simultaneously performed and can be done using various techniques. The surgeon may use the patients own bone, harvested from the hip, or a spacing device (also called a cage) packed with banked bone.


 
 
 
 
 
A strut of bone is taken from the hip. The shape may vary according to the surgeon’s choice
 
 
 
 
 
The disc is removed
 
 
 
 
The disc has been removed
 
 
 
 
The strut of bone harvested from the hip has been inserted into the disc space
 
 
 
 
Sometimes the disc-spacer is held in by a metallic plate
 
 
 
 
Recently, artificial disc replacement has been used in some centres. In the cervical spine, this remains an experimental procedure, but early results appear to be promising. Patients should discuss this option with their surgeons. The indications and contra-indications are highly specific and all South African spine surgeons are well aware of the guidelines as laid out by the Spine Society.
 
 
 
The nerve root canal has been unroofed
 
Nerve Root is lifted to reveal intervertebral disc
 
Intervertebral disc fragment can be removed
 

Pre-operative CT scan
Post-operative CT Scan showing extent of bone removal

POST-OPERATIVE EXPECTATIONS


Most patients have to use a collar after surgery. If a fusion was done, they must use a collar for about 6 weeks. Hospitalization is usually for 5 days or less.

Surgery is good for relief of symptoms, especially in the arms and fingers. Some neck pain may persist. Therefore a post-operative exercise programme must be commenced.

However, about 5% of patients do not improve after surgery. Also, some complications may occur for example bleeding, infection, hoarseness of voice due to bruising of nerves in the throat, and injury to the nerves or cord. The posterior approach is associated with a risk of recurrent disc prolapse. With fusion operations, there is a risk that, with time, the vertebra above or below the fused segment may suffer a similar fate

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