Spinal Instability

The spine changes during life. There are associated problems that can arise during this process. In this case there is a suspicion that the pain is the result of reduced stability around a joint in the lower back. This handout is an attempt to further explain what is happening.

The “lower back “ is called the “lumbar spine”. There are 5 lumbar vertebra stacked one on top of the other. Each is joined to the next by 3 separate joints. These joints allow movement to occur while attempting to keep the vertebra in a position where it can cope with the loads that pass along the spine. To understand the problem we must first look at the function of these joints and changes that occur in them over time.

a side view of the spineThe Joints

  1. The main blocks of bone, the vertebral body, stack in the front portion of the spine. Between each bone is a specialised cartilage known as the disc. This acts a little like a shock absorber between the bones while being flexible enough to allow movement. It is the normal changes that occur within the disc that sometimes leads to a problem.

  2. The other 2 joints are between the bones themselves and are called the “facet joints”. They are situated behind the disc with one to the left and one to the right side. These joints are like most others in the body (e.g. hip, knee, and elbow…). Each has a joint capsule that holds the bones together and a lubricating substance inside.  Ligaments and muscles add further support to the facet joints. They form part of the ring of bone that protects the spinal cord. However in the low back their main role is to limit movements that might damage the disc or spinal cord.

Normal Changes

The disc develops fissures or cracks as we get older. These usually occur in the inner part of the disc. The outer wall of the disc then comes under more strain. As this occurs the disc looses water content and narrows. This means that the space between the bones gets less and this leaves the facet joints more compressed.

These cracks in the disc allow more movement to occur between the adjacent vertebra. For instance the vertebra might be able to slide further forwards when bending or backwards when arching the back or to the side when bending side ways. While the actual increase in this rocking type movement is only small it has several effects.

  1. The facet joints, now under more pressure because of the narrowing of the disc, also have to work much harder to stop the increased movement.
  2. The outside wall of the disc comes under more strain because there is less support from the inner portion of the disc
The diagrams above are a side view of the spine, in cross section to show the inside of the disc.

The lumbar segments must then rely more on the surrounding muscles and ligaments for support. These act like the guy ropes of a tent. If these muscles and ligaments are also in poor condition the segments start feeling very “fragile”. The body reacts to protect the area and does so by producing pain and a feeling of stiffness. This limits movement and lessons the load on the joints.

Commonly the area will ache and feel stiff during movement. Often there can be acute twinges of pain that “take my breath away” or cause an involuntarily yelp. This usually happens when moving suddenly or when starting to move after being still for a while.

Are X-Rays Or Scans Needed?

The majority of the diagnostic process comes from looking closely at the symptoms produced by the problem, the limitation of function, and a thorough examination. In most cases x-rays and scans are used to “fill in parts of the puzzle” or confirm a diagnosis. When the diagnosis is quite clear then it is better to avoid unnecessary tests as it has been shown that their results don’t significantly influence the treatment.

Most often further imaging studies are required when the problem is not responding as expected, when a surgical solution is being investigated, or when the symptom behaviour of the problem is atypical. In these cases the information we gain is very important.

So What Is The Answer?

In essence the stability of the joint must be improved. This is sometimes done by surgically fusing together the vertebrae at fault, a last resort. Most are managed without surgery and a solution based around self-management offers the greatest chance of independence from treatment and a sustainable improvement.

First and foremost there is a need to increase the support around the joint. The muscle system is targeted to supply the support. There are some specific muscles that act to stabilise the spine. There are quite specific exercises to improve both muscle condition and its function in protecting the joint.

The second component to managing the problem is in becoming aware of the things that provoke the problem or settle the pain down when present. From this we can become skilled in minimising the stress on the joint and give it less to complain about. Likewise when the pain is present there is likely to be a way of settling it quickly.

Each problem is different and unfortunately this means there is no recipe of exercises that are right for everyone. It is important to remain as active as symptoms allow. The rule to follow is that it is all right to cause some pain during movement or activity as long as the pain settles within 1 hour of changing position or stopping the activity. It is also important to note that it is not necessarily the most vigorous activity that does the most damage, in a lot of cases it is in fact the position we get into most often during the day (eg. sitting). Guidance is normally required to set up a problem specific and effective self-management programme.