(Also known
as Slipped disc; Disc herniation; Pinched nerve)
HOW ARE THINGS SUPPOSED TO WORK?
THE
INTERVERTEBRAL DISC
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 The
spinal cord is protected by the bones of the spine, called vertebrae |
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 Between
these bones are fibrous cushions called inter vertebral discs which
help absorb impact and help with movement |
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 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. |
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 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 |
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| Gel-like
nucleus |
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| Tough,
fibrous annulus |
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| Retaining
Ligaments |
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| Inter
vertebral Disc |
WHAT GOES WRONG?
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| Varying
degrees of bulging discs, resulting in a complete disc prolapse |
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prolapsed portion of the disc may compress on nerve roots |
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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:
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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:
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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
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CT Scan; MRI Scan This gives a more detailed picture
of spinal cord, disc, ligaments and nerves and will identify a
disc protrusion
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Axial
& Sagittal Myleogram showing cervical disc herniation |
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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.
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WHAT TREATMENTS ARE 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:
- 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.
- Use of Neck Collar
- 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.
- 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.
- 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.
- Physiotherapy: Physiotherapists may instruct you on specific
exercises and can be done at home or may require a visit to the
physiotherapist.
- Traction, electrical stimulation, hot & cold packs and manual
therapy are often used
- 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. |
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strut of bone is taken from the hip. The shape may vary according
to the surgeon’s choice |
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| The
disc is removed |
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| The
disc has been removed |
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| The
strut of bone harvested from the hip has been inserted into the
disc space |
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| Sometimes
the disc-spacer is held in by a metallic plate |
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| 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. |
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| The
nerve root canal has been unroofed |
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| Nerve
Root is lifted to reveal intervertebral disc |
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| Intervertebral
disc fragment can be removed |
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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
© Copyright of the South African Spine Society |
