Unstable Spine

What Is It?

An unstable spine is a common spinal condition which can be caused by a number of factors including trauma and degenerative spine disease. The spinal column is composed of spinal bones, the vertebrae, as well as dozens of joints, ligaments, tendons and muscles that hold it all together and give it strength and stability. Normally, the spinal column, which protects the spinal cord and spinal nerves within, is stable, meaning that it is firmly held but all its supporting tissues in proper position and alignment. There is a certain degree of normal movement that the spine has and this is how we bend, arch our back and twist.

However, too much mobility of the spine, spinal instability, can be a problem. Normal movements of the spine protect the spinal cord and nerves within the spine. However, excessive or abnormal movements can cause damage to these important structures. If the spinal cord or nerves are compressed, stretched or otherwise injured by movements of the spine, they can suffer damage which can lead to disability including paralysis and/or loss of sensation.

An unstable spine can result from anything that causes damage to the supportive structures of the spinal column. Most obviously, this can include acute traumatic injury of the spine. If enough force is applied to the spine during an accident (fall, automobile accident, etc.) tearing or breaking of the structures of the spine can result. If the tissue damage is severe enough, an unstable spine results and excessive or abnormal movements can be possible. These abnormal movements can cause symptoms or even lead to permanent damage to the spinal cord and nerves.

Spinal instability can also result from degenerative disease. As we all age we put wear and tear on our spine, some more than others. Over time this can lead to disease of the spine, termed degenerative spine disease. There are many examples of degenerative disease of the spine including herniated discs and spinal stenosis. If the damage to the spine is great enough over time, it can lead to laxity of the joints, muscles and ligaments that hold the spine together and give it stability. If this laxity is great enough, abnormal movements and positions of the spine may occur. These can compress the spinal cord or nerves and cause symptoms including pain, weakness and loss of sensation.

What Types of Symptoms Are Typical?

The specific symptoms of an unstable spine depend on the cause, the location of the instability, its severity and several other factors. In the case of an unstable spine resulting from degenerative spine disease, back pain is a common symptom. The pain is typically felt in the affected area of the back and is typically worse with movement or with certain positions.

If the instability and abnormal movement of the spine causes compression or injury to the spinal cord or spinal nerves, neurological symptoms can also result. These can include pain which radiates into an extremity (arm or leg), weakness or paralysis and/or loss of sensation (numbness or tingling). Other types of spine disease can cause similar symptoms. However, these symptoms associated with spinal instability are often worse with movement or in certain positions.

If the instability is great enough, severe compression of the spinal cord or nerves can result, leading to permanent neurological symptoms including paralysis and/or loss of sensation.

How Is The Diagnosis Typically Made?

A thorough neurological exam can help to pinpoint any neurological disability including weakness and sensory changes. However, it does not generally diagnose the underlying spinal condition. To do this, imaging is needed to visualize the structures of the spine.

After an acute trauma with evidence of spine trauma, the spine is usually imaged thoroughly in the hospital to assess for any fractures, dislocations or other traumatic injury to the spine. This can include plain x-rays, CT and MRI scans of the spine.

Likewise, in a patient without trauma with symptoms consistent with spinal disease or an unstable spine imaging studies are often ordered to assess the spine. While standard CTs and MRIs of the spine can often demonstrate many forms of spinal disease, instability can be difficult to assess because it is related to movement and these imaging studies are static (the patient is lying still in one position). Therefore, to fully assess instability accurately, dynamic studies are often done. This most commonly includes what are called flexion-extension films. The patient's spine is imaged by x-ray in both fully flexed (bent forward) and fully extended (bent backward) positions. The two images are then compared and any abnormal movements can be seen.

What Are Some Common Treatments?

If a patient is demonstrated to have clear spinal instability they will often be recommended to undergo some form treatment, particularly if they have significant symptoms. In cases of very mild instability this may initially just include conservative measures such as rest and wearing a brace to aid stability.

In more severe cases of instability a spinal fusion procedure may be recommended. These surgical procedures aim to fuse the abnormal movement of the spine so that no movement is allowed at that level of the spine. This can be accomplished in various ways but generally involves use of instrumentation (metal bone screws, rods and cages) to hold the spine in position while it heals and fuses. Grafts of bone (either from the patient or from another source) are often used to help bolster the fusion and initiate fusion of the bones of the spine.

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Important Note: This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.

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