What is it?

In spondylolisthesis one of the vertebra slips forward on the vertebra below it. The nerves that exit through the foramina can be compressed in such a case. The disc also becomes damaged as the forward movement takes place. The term is a Greek term and is derived from the word “spondylos” which means vertebra and listhesis which is a term which means to slip or to slide.

There are different types:

Inborn (congenital) - in this case the slippage is caused by abnormal bone that does not develop normally at birth and predisposes the vertebra to slip.

Isthmic - in this case there is breakage of the elements that support the joints, which in turn are responsible for keeping the vertebra in place. This breakage is called spondylolysis.

Degenerative - In this case the discs between the vertebra are the main culprits. With age the discs lose some of their water content and become weak (degenerative). This leads to slippage of the vertebra. This is also the most common form of spondylolisthesis.

Traumatic - trauma can lead to a fracture of the stabilizing complex that houses the intervertebral disc and this in turn leads to the slippage.

Post-surgical - overzealous decompressions of the lumbar spine can lead to instability and the inability of the intervertebral joints to stop slippage from occurring.

Pathologic spondylolisthesis - this is a less common form of spondylolisthesis and is when the bone is weakened by a pathological process such as a tumor, infection, bone disease or osteoporosis

What are the symptoms?

Back pain is the most common symptom. Many people are however unaware that they have this condition. Spondylolisthesis leads to mechanical back pain and referred pain. When the slippage is so sever that a nerve root is compresses it can lead to radicular pain. See the section on back pain.

How is it diagnosed?

It can be diagnosed on X-ray, CT scan and MRI scanning. There are different grades of spondylolisthesis and the grading is based on the amount of slippage that has taken place.

Grade I - up to 25% slippage
Grade II - 25% to 50% percent slippage
Grade III - 50% to 75% slippage
Grade IV - more than 75% slippage

MRI scanning is used to evaluate not only the amount of slippage but also whether there is compression of any of the nerves.

What is the treatment?

As a general rule, Grade I and grade II slips can be treated without an operation. The symptoms are generally limited to mechanical back pain and referred pain. These are treated with the usual conservative therapies of pain tablets, anti inflammatory tablets, physiotherapy and chiropractic manipulation. The back can be supported by following an exercise program through your local gym and preferably overseen by a biokinetician. External support can be given by a brace.

Using facet blocks and facet nerve denervation by radio frequency can be very effective in the right hands. Sacral or epidural steroid injections can also be of value.

There are generally two indications only for an operation. The first is ongoing disabling back pain that is not relieved by any conservative measure and a definite loss of quality of life. The second indication is impending permanent nerve damage. This is usually indicated by sciatica or dysfunction of the nerves that supply the bladder and the bowel as well as sexual function. The sacral nerves supply the outonomic (automatic) function of bowel, bladder and sexual function and can be compressed if the listhesis is severe.

The first part of the operation is a decompressive laminectomy to free the nerves up and this is usually supplemented by a pedicular srew spinal fusion. This is because the spine is even further destabilised by doing the laminectomy. Please see the operative sections foe a description and explanation of these operative procedures.

Are there any complications of the treatment?

Conservative therapy has as the only complication the fact that it might be unsuccessful and therefore not prevent a spinal operation. It should however, in the absence of an impending permanent nerve damage be the first line of treatment.

See the chapter called my back operation to see the list of potential complications of spinal surgery. Spinal surgery is never without risks and some of them can be very severe, their occurrence are however rare.

What are the long-term expectations?

For grade I and II spondylolisthesis conservative therapy can be successful in up to 80% of cases. Surgical treatment can be successful in up to 90% of people. There has to be an ongoing commitment from the patient to strengthen their back and to keep good back habits for the rest of their lives. Please see the chapter on good back habits in the chapter called back care.