What is Spondylolisthesis?

Vertebra in the spine slip forward

Spondylolisthesis is a medical term used for describing vertebral slippage in the spinal column. The human spine has a perfectly aligned S shape, but spondylolisthesis distorts this alignment. With spondylolisthesis, a vertebra slips forward or backward onto the vertebra below.

Depending on the cause, spondylolisthesis can be classified into 5 different types: degenerative, isthmic, dysplastic/congenital, pathogenic, and traumatic spondylolisthesis.

Degenerative Spondylolisthesis:
Most commonly caused by degenerative diseases. It’s usually found in older people and is especially common among African-Americans.
Isthmic Spondylolisthesis:
Affects both adults and children. It is generally caused by a small fracture(s) in the pars interarticularis, part of the facet joint.
Dysplastic Spondylolisthesis:
Also known as congenital spondylolisthesis, is a result of a congenital birth defect.
Pathogenic Spondylolisthesis:
This form of spondylolisthesis is caused by diseases such as tumors or infections.
Traumatic Spondylolisthesis:
The result of a bone fracture from a traumatic event.

Although vertebral slippage from spondylolisthesis can occur anywhere on the spine, it is most common in the lower back and is a major source of lower back pain. Even though in many cases, spondylolisthesis symptoms can be improved with non-surgical treatments, although serious spondylolisthesis may need surgery.

Spondylolisthesis Grades

The severity of spondylolisthesis is measured by the degree of slippage, or the percentage of one vertebral body that has slipped forward on another. The higher the spondylolisthesis grade, the more severe the condition is. Each of the four spondylolisthesis grades represents a 25% slippage. 

doctors note

Note From Dr. Liu:

Spondylolisthesis grades dictate the proper course of treatment. Grade 1 and 2 spondylolisthesis are generally responsive to conservative treatments, but higher grades often require surgery.

healthy section of the spine in proper alignment
Figure 1a. A healthy spine with no vertebral slippage.
spondylolisthesis showing vertebral collapse
Figure 1b. Spondylolisthesis seen in an unhealthy spine.