What Is Spondylolisthesis?

Spondylolisthesis is a condition in which a vertebra in the lumbar (lower) spine slips out of normal position, sliding forward (or sometimes backward) relative to the vertebra beneath it. It can be the result of an injury, lower back stress associated with sports, or age-related changes in the spine.

Depending on the extent of movement of the vertebra involved, symptoms can range from none at all to severe pain caused by pressure on a spinal nerve.

Spondylolisthesis usually is diagnosed with an X-ray. Low-grade spondylolisthesis may be relieved with non-invasive measures, while more severe cases may require a surgical procedure.

Types of Spondylolisthesis

The vertebrae are the box-shaped bones stacked on top of each other that make up the spinal column. Each vertebra should be neatly stacked on the one above and below. The spinal column has a normal S-shaped curvature when viewed from the side, but each vertebra should be neatly positioned on top of the vertebra below.

In spondylolisthesis, the vertebrae shift from their normal position. As a result, the condition is often referred to as "slipped vertebrae." Most often, this is a very slowly progressive condition with different types that include:

• Isthmic spondylolisthesis: This results from spondylolysis, a condition that leads to small stress fractures (breaks) in the vertebrae. In some cases, the fractures weaken the bone so much that it slips out of place.
• Degenerative spondylolisthesis: Degenerative spondylolisthesis is related to spine changes that tend to occur with age. For example, the discs can start to dry up and become brittle; as this occurs, they shrink and may bulge. Spinal arthritis is another age-related condition. Degenerative spondylolisthesis can cause spinal stenosis, in which the bones narrow and put pressure on the spinal cord.
• Congenital spondylolisthesis: Congenital spondylolisthesis results from abnormal bone formation that is present from birth, leaving the vertebrae vulnerable to slipping.

Less common forms of the condition include:

• Traumatic spondylolisthesis: With this, a spinal fracture or vertebral slipping occurs due to injury.
• Pathological spondylolisthesis: In this case, spondylolisthesis occurs due to another disease, such as osteoporosis, a tumor, or an infection.
• Post-surgical spondylolisthesis: This occurs when spine surgery results in slippage of the vertebrae.

Symptoms

Many people with spondylolisthesis have no obvious symptoms. Sometimes the condition is not discovered until an X-ray is taken for an unrelated injury or condition.

The most common symptom is lower back pain that can radiate to the buttocks and down the backs of the thighs. The symptoms may get worse during activity and subside during rest. Specifically, you may find that symptoms disappear when you bend forward or sit and get worse when you stand or walk.

This is because sitting and bending open up the space where spinal nerves are located, relieving pressure. Other potential symptoms include:

• Muscle spasms
• Tight hamstrings (muscles in the back of the thigh)
• Difficulty walking or standing for a long period of time
• Changes in gait

Severe or high-grade slips may result in pressure on a nearby spinal nerve root, causing tingling, numbness, or weakness in one or both legs.

Causes

Children involved in sports such as gymnastics, football, and diving tend to be at an increased risk for isthmic spondylolisthesis. These sports require repeated spinal hyperextension, which can cause a stress fracture of the pars interarticularis in the L5 vertebra.

Unless the hyperextension exercises are stopped to give the bone time to heal, scar tissue can form and prevent the bones from ever healing properly. This can lead to spondylolysis or stress fractures in the pars interarticularis, a condition that commonly leads to spondylolisthesis.

It's possible to be born with spondylolysis or spondylolisthesis, but both conditions can also develop from an injury, a disease, or a tumor.

Degenerative spondylolisthesis, the most common type, tends to affect adults over the age of 40. Older age, female gender, larger body mass index (i.e., being overweight or obese), and conditions that can affect the spine, such as degenerative disc disease (DDD) and osteoarthritis, are thought to be factors that elevate the risk for this condition.

Diagnosis

Your healthcare professional will first talk to you and/or your child about symptoms, medical history, general health, and any participation in sports or physical activities. Then, they will examine the spine, looking for areas of tenderness or muscle spasms, and assess whether there are problems with gait or posture.

Next, your practitioner may order imaging studies, including:

• X-rays: These help distinguish between spondylolysis and spondylolisthesis. An X-ray taken from the side is also used to assign a grade between I and V, based on the severity of the slippage.
• Computed tomography (CT) scans: These provide greater detail than X-rays and help your healthcare professional prescribe the most appropriate treatment.
• Magnetic resonance imaging (MRI) scans: An MRI focuses on the body's soft tissues and can reveal damage to the intervertebral disks between the vertebrae or compression of spinal nerve roots.

There are five spondylolisthesis grades, each representing an incremental 25% increase of slippage in the vertebra.

Treatment

Spondylolisthesis is treated according to the grade. For grades I and II, conservative treatments are often sufficient, including nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, physical therapy, home exercises, stretching, and the use of a brace. In physical therapy, core strengthening and stabilization exercises are emphasized.

Over the course of treatment, periodic X-rays may be taken to determine whether the vertebra is changing position.

For high grades or progressive worsening, spinal fusion surgery may be recommended. During this procedure, the affected vertebrae are fused together so that they heal into a single, solid bone.

During the procedure, the surgeon will realign the vertebrae in the lumbar spine. Small pieces of bone—called a bone graft—are then placed into the spaces between the vertebrae to be fused. Over time, the bones grow together, much like when a broken bone heals. Metal screws and rods may be installed to further stabilize the spine and improve the chances of successful fusion.

In some cases, patients with high-grade slippage also have compression of the spinal nerve roots. If this is the case, a procedure known as spinal decompression can help open up the spinal canal and relieve pressure on the nerves.

Summary

Spondylolisthesis is a spine condition in which a vertebra slips out of position. This may cause symptoms like low back pain and back stiffness. Young athletes are often at increased risk for spondylolisthesis as overextending the spine—which commonly happens in sports like football and gymnastics—is one of the most common causes of the condition.

To diagnose spondylolisthesis, a healthcare professional will review a person's symptoms and medical history, and they'll use imaging tests like X-rays and CT scans to analyze the spine and determine the severity, or grade, of the problem.

Lower-grade cases of spondylolisthesis typically respond well to conservative treatment like anti-inflammatory medication and physical therapy, while higher-grade cases may require surgery.

A Word From Verywell

With nonsurgical and surgical treatments available, having spondylolisthesis that is causing symptoms does not mean you have to live in pain.

In most cases, it's possible to resume activities, including sports, once the condition has been treated. If symptoms reappear after treatment, tell your doctor so that they can determine what strategies are needed to relieve them and restore your quality of life.