Isthmic spondylolisthesis occurs in the lumbar spine when a fracture of the isthmus (shown below in red) causes one vertebral body to slip forward on top of the one below it.
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Cause of isthmic spondylolisthesis
A small segment of bone called the isthmus connects the facet joints at the back of the spine. The isthmus is thin and has a poor blood supply, making it susceptible to stress fractures. A fracture of the isthmus usually occurs due to cumulative stress to the spine, not from a sudden trauma. When a fracture like this occurs, it is known as a spondylolysis.
Sometimes this type of fracture can lead to a slippage of the vertebrae. When this occurs, the condition is known as spondylolisthesis.
Isthmic spondylolisthesis is a fairly common condition among young athletes involved in sports that involve repeated hyperextension of the lower back (bending backwards), such as in gymnastics.
Location and symptoms
This type of injury usually occurs at the L5-S1 segment, located in the lowest level of the lumbar spine.
The severity of the slippage is measured using a scale from 1 to 4 after taking a side-view X-ray .
Sometimes there is no pain associated with isthmic spondylolisthesis. A deep ache in the lower back is most common if there are symptoms. Pain from isthmic spondylolisthesis tends to be worse when standing, walking, or during activities that involve bending backward. There may also be tightness in the hamstrings.
Another source of pain may be due to nerve root compression, which can occur if the disc space between the two vertebrae wears out. The root compression may cause radiating pain, numbness or weakness in the legs.
Non-surgical treatment for this condition is similar to how you would treat other conditions that cause low back pain, including using medications, heat and cold therapy, physical therapy, manual manipulations, or injections. If none of these treatments work to relieve your pain, you may have to consider surgery.
For a full description of all your treatment options, please read Spondylolisthesis Treatment.
Fortunately, most people with this condition won't have symptoms, and for those that do have symptoms, only around 15% -20% will require surgery. Make sure to check out all of our videos on back pain in our back pain videos section.