What is degenerative spondylolisthesis?

Degenerative Sponylolisthesis Explained

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Anatomy of the vertebral column. The lumbar spine is labeled L1-L5.

Wear and tear can occur in the spine just as it does in the hip or the knee. These wear and tear changes, also known as degenerative changes, can take on a few different forms when occurring in the spine. These range from degenerative disc disease, to spondylolisthesis (to be discussed here), to degenerative scoliosis (curving of the spine), and many others. A number of these changes can occur in tandem, or at the same time.

The term spondylolisthesis refers to the slippage of one vertebra over another. In the case of degenerative spondylolisthesis, this happens due to osteoarthritis related changes in the spine. This most commonly happens in the lower back, also known as the lumbar spine. The lumbar spine is composed of 5 vertebra that are numbered from 5 at the bottom up to 1 towards the top of the lower back. Each separated by a squishy disc that allows for motion between each level. Behind the intervertebral discs lie two facet joints.  Each vertebra is connected by three joints in total (1 intevertebral disc, and 2 facet joints) to the vertebra above and another 3 joints to the vertebra below.

The most common level for developing spondylolisthesis is the L4-5 level. The condition typically effects people over 50 years of age, and affects women more commonly than men. The degeneration often starts with the vertebral disc.

As the disc deteriorates further and further it loses some of its water content, which leads to the disk losing its ability to provide cushion between two vertebra. As the disk loses water content, and the disc space (the space between two vertebra) narrows, the ligaments that line the vertebral bodies start to buckle inwards.

This can lead to developing of a small amount of instability that leads to more wear and tear. As degeneration progresses the facet joints (described above) begin to deteriorate, and eventually one vertebral body can slip either forward or backwards over the one below.

The symptoms of degenerative spondylolisthesis are fairly variable. Low back pain is a common complaint. As the facet joints deteriorate, and swell in the process, they can decrease the size of the foramina or small canals that nerve roots run through. This can cause severe shooting leg pain, numbness, and weakness in one or both legs. As the amount of slippage of one vertebra over the vertebra below increases, the space available for the spinal cord decreases, and eventually a central stenosis can develop where the spinal cord (which at this level is made up of nerve roots) can get pinched. This is a much more serious problem, can present itself as leg weakness, numbness, changes in reflexes, as well as changes in the control of one’s bowel or bladder function, and numbness in the groin area.

If any of the last 3 symptoms develop (bowel/bladder dysfunction or groin/perianal numbness) this is an emergency and should be evaluated by a physician promptly.

The symptoms above have a wide range from mild back pain, to severe emergencies, a common question is whether one’s symptoms progress? Studies have shown that approximately One third of patients will experience progression of spondylolisthesis, and worsening symptoms. People that develop symptoms of leg weakness and numbness have been shown to have a higher likelihood of progressing. The treatment of degenerative spondylolisthesis has a broad range from conservative measures such as neuromodulatory drugs, anti-inflammatory medications, physical therapy and steroid injection to more invasive options such as surgery involving decompression and fusion of the spine. The choice of therapy depends on severity of symptoms, and details of the successes and failures of various treatment options will be discussed in a later article.

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