Many of us who learned to play tennis in the ‘80’s and 90’s were taught to emulate Agassi’s mini-step style of movement. Small steps were believed to make you more adaptable, allowing you to adjust for the unexpected bounce of the ball. Then along came Pete Sampras with his long legs, loping gait and highly successful career. Almost overnight mini-steps were out and coaching focused on increasing the speed you could run to the ball. What a surprise for those of us who have lived through both of these style paradoxes to find out that Agassi’s movement was not a philosophy but rather the result of an impairment imposed on him by his back – spondylolisthesis.

What is Spondylolisthesis

Agassi and approximately 7% of the population suffer from a structural defect in the spine called spondylolisthesis. This condition is characterized by a fracture (lysis) that causes the front body of the vertebrae (spondylo) to separate (thesis) from the bone and joints located at the back of the spine. This defect allows the body of the vertebra to shift forward (thesis) in relation to the rest of the vertebral column, leaving this section of the spine inherently less stable than other areas of the spine.

What Causes Spondylolisthesis

When this conditions occurs in young people the cause has been attributed both to genetics and to injury. Injury has recently gained more support as it is well known that participants in certain sports are more at risk for this condition. Gymnasts, divers and football players all have a higher frequency of spondylolisthesis than what is typical for the rest of the population. It is speculated that immature bones cannot withstand the forces generated by these sports and the bone breaks under the stress. It is not known why the fracture never heals.

How serious is Spondylolisthesis?

Fortunately most spondylolistheses are stable, however when first diagnosed it is important to periodically monitor the condition to be sure that the shift is not increasing. The degree of instability can be quantified on X-ray by measuring the amount of shift in relation to the adjacent stable vertebra. The most common, and least unstable shift, is labelled as a grade 1 when the vertebral body shifts forward from 1-25% of its depth. There are a total of 5 grades with each level increasing by 25% until it reaches the extremely rare grade 5 where the front of the vertebrae has shifted completely forward of the spine.

Symptoms of Spondylolythesis

The age at which someone first experiences back pain can often be a marker for the presence of this condition. Whereas most people can expect to experience their first episode of back pain after age 30, the pain associated with a spondylolisthesis frequently manifests itself in our teens. The pain is often caused by certain movements straining the fracture site as it allows movement at the area commonly called a pseudoarthrosis (false joint). For example the sufferer may feel pain from the compression of the two surfaces while he or she is leaning back to serve the ball. It may also be caused by the increased stress on the disc. The firm attachment of the intervertebral disc to the margins of the adjacent bone is under more strain by the vertebra’s forward displacement.

Treatment of Spondylolithesis

The treatment for this condition depends on whether the condition is acute or chronic and the degree of instability. A highly unstable listheses will require surgery however most people with this condition do well with more conservative approaches. During the acute stage, the pain from the irritation of the pseudoarthrosis and/or the disc means that therapies which help to control pain are the priority. Ice, advice on modifying activity, rest, medication, acupuncture and/or a variety of electrical modalities can all be beneficial. Over the long term the goal shifts to strategies to prevent further strain on the weakened structure as this is what will ultimately limit future painful episodes and prevent additional damage.

Rehabilitation and prevention programs’ primary focus should be on posture and adequate muscle strength. This approach will help to ensure that the stress of everyday movements can be absorbed by the muscles rather than being transmitted to the mechanically challenged vertebral-disc complex. As with all back pain the importance of having a strong core cannot be overemphasized however in this condition you may also need to broaden the scope of exercises as depending on where the defect is located you will be more prone to specific muscular weaknesses. For example the most common location for a spondylolisthesis is in one of the bottom two vertebrae of the low back, L4-5 or L5-S1. The problem with this location is that it houses the nerves that supply the muscles of the buttock and outer hip and is a possible cause of sciatica. Damage in this area can cause compression to the nerves and this means it is more likely that strength will be lost in the muscles they supply.

Compensation and muscle weakness’

Although Agassi does not reveal the location of his spondylolistheses he alludes to having these specific muscle weaknesses when he attributes his back to the cause of his pigeon-toe gait. Having a toed-in position is often an indicator that the buttock muscles (gluteus maximus) and outer hip muscles (gluteus medius and minimus) are relatively weak. A postural and gait mal-alignment results when the muscles which turn the legs outward do not ounteract the pull of the muscles turning the legs in. Unfortunately this over-reliance on the inner thigh and groin muscles causes tightness and compensatory movement patterns which increase the risk of injury, particularly in someone like Agassi who competed at such a high level. His biography shows the outcome of these imbalances as he was often unable to finish matches once his over-worked groin muscles started to spasm.

Despite all of these anatomical stresses and strains many people who have a spondylolisthesis can be completely symptom free and may only find out that they have had this condition much later in life when they are being investigated for age related back pain. Having good core muscles is invaluable in counter-acting the effects of this condition and preventing pain.

The effects of a good training program can be seen in this example of Andre Agassi, as not only was he able to play tennis with this condition he was able to excel at it.