What is lumbar instability?

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Lumbar instability is a spine condition in which there is abnormal mobility or articulation between two or more contiguous vertebrae, which causes great pain. There is excess movement between vertebrae and progressive degeneration of the intervertebral joints. 

The main causes of lumbar instability can be classified as:

  • Degenerative: The most frequent cause of spinal instability in adults is a degeneration or early wear of intervertebral discs, the most important components of the spine, which causes abnormal mobility of these structures. This condition occurs in people with a greater genetic predisposition and those who are exposed to overexertion. These degenerative problems are increased by postural problems, poor physical condition, muscle failure, sedentary life-style, overweight, trauma, etc.
  • Congenital:
    • Spondylolisthesis is the most frequent of these conditions, caused by spondylolysis (bone defect at the junction of the facets).
    • Abnormal lumbo-sacral transition (lumbarization of the first sacral vertebra or sacralization of the fifth lumbar vertebra).
    • Abnormalities in the alignment of the vertebral bodies, such as is the case in scoliosis.
  • Acquired:
    • Pathologies that affect the lumbar spine, such as infections or tumors.

From Instituto Clavel, as spine specialists, we recommend that all patients (except for specific cases with especially marked instability) should be treated with conservative methods at the beginning. They should avoid sudden efforts and movements, and static positions that cause sustained tension of the lumbar muscles, as well as any habit that worsens the prognosis of the disease. Conservative treatments require prescribing anti-inflammatory drugs for short periods, muscle relaxants and appropriate physiotherapy and kinesiotherapy programs. Since the degeneration of passive stabilizing structures (ligaments, articular cartilage and discs) of the spine is irreversible, the best prevention strategy is to preserve good health and good functioning of the dynamic mechanisms responsible for spine stability, such as the spinal muscles.

For all patients in which this pathology is very advanced, and who do not respond satisfactorily to less aggressive treatments, the option of undergoing surgery should be considered.

There are several possible types of surgical interventions for intervertebral stabilization, but almost all will require some type of implant that performs the function of stabilization to replace the anatomical structure that has failed.

Whenever possible, a minimally invasive surgery (MIS) technique is applied so as to avoid compromising spinal muscles. Among the different techniques of this type we can find lateral approach arthrodesis (XLIF), applicable to the levels between L1 and L5, or anterior approach arthrodesis, for the levels between L3 and S1, in which the disc is replaced with a mobile (ADR) or fixed (ALIF) implant depending on the severity of the instability. This anterior approach is also the one performed in the great majority of cases of cervical instability, and in this procedure, it is necessary to decide between using mobile or fixed implants depending on the severity of the case.

In a few specific cases, it will be sufficient to perform less aggressive surgery with implantation of an interlaminar or intra-facial distraction device, located in the most posterior part of the vertebrae.

When it is necessary to decompress nerve structures such as the medulla or nerve roots, more open surgery will be required to ensure the correct release of the structures. Other times it is necessary to add a stabilization mechanism at the posterior third of vertebrae to achieve sufficient correction in cases of pronounced instability, especially if there are multiple levels affected. It is in these two cases when the benefits of the posterior approach are clear and arthrodesis is performed with transpedicular screws and TLIF type intersomatic cages.

In our clinic specialized in spine surgeries, we explain you that when applied correctly, all these techniques are clearly effective in achieving intervertebral stability. The application of one or the other will depend on the needs of each case, which is the reason why an individual study of each patient is indispensable. All of them can be applied separately, or combined for a better result in cases where only one surgical procedure is not enough.