Lumbar instability: definition and treatment (Is it serious?)

THElumbar instability is a spinal movement disorder. It is characterized by abnormal mobility or abnormal articulation between two or more contiguous vertebrae. It can be particularly very painful. In this article, we will talk about causes and treatment of lumbar instability.

Definition of lumbar instability

Lumbar instability describes a greater than normal range of motion between two vertebrae. This results in particular from a degenerating disc which becomes unable to support the weight of the body.

When a patient suffers from lumbar instability, there is a excessive movement between the vertebrae and gradually a degeneration of intervertebral joints. This can affect the structures of the nervous system that pass through them.

La abnormal mobility between two or more vertebrae may increase the risk of osteoarthritis or spinal arthritis, as well as the risk of developing bone spurs (osteophytes).

Causes of lumbar instability

 

We can classify as follows the causes of lumbar instability.

Degenerative cause

The most common cause of spinal instability in adults is degeneration or premature wear of intervertebral discs. Being the most important part of the spine, their involvement causes abnormal mobility of these structures. This can happen in people with a great genetic predisposition and whose body is subject to overwork. These degenerative problems are increased by poor posture, poor physical condition, muscle failure, sedentary life, excess body weight, injuries, etc.

Congenital cause

The most common is the spondylolisthesis caused by a spondylolysis (bone deficit at the junction of the facet joints).

It can also be caused by anomalies of lumbosacral transition (lumbarization of the first sacral vertebra or sacralization of the fifth lumbar vertebra).

The abnormalities in the alignment of the vertebral bodies as in the case of a Scoliosis are another congenital cause of lumbar instability.

Finally, certain pathologies such as Ehlers-Danlos syndrome are associated with lumbar instability.

         

Acquired cause

This pathology of the movement of the spine can be secondary to surgery, infections or tumors affecting the lumbar spine.

 

 

Symptoms of Lumbar Spine Instability

The most common symptom of lumbar instability is pain. It can be acute or chronic and can vary with changes in posture. For example, the pain is accentuated in positions that put a lot of strain on the vertebral structures. It decreases in those who do not exert such stress.

This spinal instability can cause nerve compression. This produces a sciatic pain during movement which disappears at rest.

In some cases, this condition is asymptomatic. Otherwise, it can significantly worsen the quality of life of patients. Therefore, early diagnosis is essential to receive treatment as soon as possible and delay the progression of instability.

Diagnosis of lumbar instability

Le diagnosis of spinal instability based on tangible signs. These are factors that can be objectively measured or determined. The doctor will be interested in the lifestyle as well as the medical history of the patient. He can also carry out a battery of examinations.

• MRI and computed tomography which provide information on the condition of the disc concerned.
• X-ray radiography that makes it possible to study changes in the bone structure.
• A spinal probe that helps recreate conditions that may be causing pain.
• Clinical tests may suggest lumbar instability (such as Prone Instability Test)

Treatments for lumbar instability: what should be done?

In general, specialists in spinal pathologies recommend that all patients (except specific cases with particularly marked instability) be treated with conservative methods in first intention. It is only in the absence of improvement that a surgical intervention should be considered.

Conservative treatments

First, the patient should avoid:

• overexertion;
• sudden movements and the maintenance of continuous positions which cause a sustained tension of the lumbar musculature ;
• any habit that may worsen the prognosis.

In conservative treatments, doctors also prescribe anti-inflammatories for short periods. Physical therapy (physiotherapy) sessions can also be beneficial for the muscles. This makes it possible to stabilize the bone or ligament lesion by working to strengthen the core muscles.

Since the degeneration of passive spinal stabilizing structures (ligaments, articular cartilage and discs) is very difficult to repair, the best prevention strategy is to maintain dynamic spinal stability mechanisms. This consists of maintaining a healthy and functional spinal musculature.

Surgical treatment

For patients whose pathology is very advanced or who do not find relief in less aggressive treatments, it is possible to resort to surgery.

There are several possible surgical techniques within the framework of the intervertebral stabilization. They almost always require the placement of an implant fulfilling the function of stabilization, replacing the faulty anatomical structure.

Whenever possible, doctors choose a minimally invasive surgical technique to respect the spinal musculature. Among these techniques, there is arthrodesis by anterior approach. This is used for levels between L3 and S1, in which the disc is replaced by a mobile or fixed implant. The choice depends on the severity of the instability.

To find out everything about lumbar arthrodesis, see the following article.

In cases where conventional stabilization could not be achieved, due to age or health issues, the doctor will opt for mild surgery. It consists of theimplantation of a spinal distraction device on the most posterior part of the vertebra.

If in addition to this the doctor needs to perform decompression of nerve structures, a more open type of surgery will be required to free the structure properly.

In case of pronounced instability, a stabilizing mechanism must be added in the posterior third of the vertebrae to achieve sufficient correction. This is especially necessary if several levels are affected. It is in these cases that the benefit of the posterior approach is obvious. The arthrodesis is therefore performed with transpedicular screws and interbody arthrodesis cages.

If these techniques are applied correctly, they can effectively restore intervertebral stability. The choice of technique to use will depend on the needs of each case. This is why an individualized study in each situation is essential. These types of interventions can be applied separately or combined to achieve a better result.

Sources

 

https://www.sciencedirect.com/science/article/abs/pii/S0168605407001791

http://www.c3rlyon.org/articles/modele_stabilite_instabilite.html