What Is Spondylolisthesis

Spondylolisthesis occurs when one vertebra slips forward in relation to an adjacent vertebra, usually in the lumbar spine. The symptoms that accompany a spondylolisthesis include pain in the low back, thighs, and/or legs, muscle spasms, weakness, and/or tight hamstring muscles. Some people are symptom free and find the disorder exists when revealed on an x-ray. In advanced cases, the patient may appear swayback with a protruding abdomen, exhibit a shortened torso, and present with a waddling gait.

Spondylolisthesis can be congenital (present at birth) or develop during childhood or later in life. The disorder may result from the physical stresses to the spine from carrying heavy things, weightlifting, football, gymnastics, trauma, and general wear and tear. As the vertebral components degenerate the spine's integrity is compromised.

Another type of spondylolisthesis is degenerative spondylolisthesis, occurring usually after age 50. This may create a narrowing of the spinal canal (spinal stenosis). This condition is frequently treated by surgery.

Diagnosis of Spondylolisthesis

A routine lateral (side) radiograph taken while standing confirms a diagnosis of a spondylolisthesis. The x-ray will show the translation (slip) of one vertebra over the adjacent level, usually the one below.

Using the lateral (side) x-ray, the slip is graded according to its degree of severity. The Myerding grading system measures the percentage of vertebral slip forward over the body beneath. The grades are as follows:

Grade 1: 25%
Grade 2: 25% to 49%
Grade 3: 50% to 74%
Grade 4: 75% to 99%
Grade 5: 100%*

*Complete vertebral slippage, known as spondyloptosis.