The medical spondylolisthesis definition gives a basic description of this condition. While this is an accurate explanation, it is important to be aware of the more in depth spondylolisthesis definition that consists of understanding the different types and grades.

Basic Spondylolisthesis Definition

The medical definition of spondylolisthesis can be explained by looking at the word itself. Dividing up the word into two parts is a simple way to remember the basic spondylolisthesis definition.

Spondylo is the first part and means spine. Listhesis is the second part, which means slippage. When you put these two parts together, the basic spondylolisthesis definition is a forward slippage or displacement of a vertebra over the lower segment. It is generally the fourth or fifth lumbar section of your spine.

This medical issue can be developmental or acquired. Developmental spondylolisthesis can exist at birth or could develop during childhood. While it may exist at this time, it is not usually noticed until later on in life. Acquired spondylolisthesis can be the result of daily stresses on your spine or from a single/repeated force of impact to your spine.

Spondylolisthesis Definition of Different Types

There are six different types of this condition. Listed below are brief descriptions of each type. This should only be used as a guide for your own informational purposes.

  • Dysplastic or Congenital – This is caused by an abnormality of the joints of the spine. It is commonly present in childhood and occurs in the lowest joint of the spine.
  • Isthmic – This is caused by a fracture through the pars interarticularis (a portion of the vertebra) that allows for slippage. This is also commonly present in childhood and occurs in the L5 to S1 level, which is the lowest joint of the spine.
  • Degenerative – This commonly occurs at the L4-5 level and is generally caused by degenerative disc disease and arthritis of the joints. This is also commonly accompanied by spinal stenosis (narrowing of the spinal canal).
  • Traumatic – This is usually caused from a fracture of the portion of the vertebra, except the pars interarticularis.
  • Pathologic – This is generally the result of a tumor or infection that erodes in the spine causing slippage.
  • Iatrogenic – This usually occurs in patients who have had extensive spinal surgery, such as a laminectomy or decompression surgery.

If you are experiencing pain or discomfort, it is important that you make an appointment with your medical physician to confirm the cause.

Spondylolisthesis Definition Based on Severity

This medical issue can also be defined by its severity. It is graded based on the amount that one vertebral body has slipped forward onto another. It is divided into five grades, with grade one being the least advanced and grade five being the most advanced. The grades are listed below:

  • Grade 1 – Upper vertebra has slipped forward less than 25 percent of the total width of the vertebral body.
  • Grade 2 – Upper vertebra has slipped forward between 25 and 50 percent.
  • Grade 3 – Upper vertebra has slipped forward between 50 and 75 percent.
  • Grade 4 – Upper vertebra has slipped forward more than 75 percent.
  • Grade 5 – Upper vertebra has slipped completely forward off the front of the lower vertebral body. Grade 5 is also known as spondyloptosis.

A treatment plan will be determined based on the severity of the slippage and symptoms. Understanding the spondylolisthesis definition by type and grade will give you a better sense of what your doctor will be explaining to you during your appointment.