Spondylolysis and Spondylolisthesis

What are spondylolysis and spondylolisthesis?

Spondylolysis is a stress fracture in the lower back. Children and teens who participate in sports that put repetitive stress on the low back, such as gymnastics, skiing, and weightlifting, are at highest risk. Some children are born with a genetic tendency to develop spondylolysis even if they do not participate in sports.

If left untreated, spondylolysis can progress to spondylolisthesis, a condition in which a vertebra, weakened by fracture, slips out of alignment with the rest of the spine. The risk of spondylolysis is higher during growth spurts.

Athletes with either condition can usually return to sports after several months of rest and physical therapy. Your child may need to wear a back brace as part of their recovery. If a vertebra is severely out of alignment, or if your child remains in pain despite other forms of treatment, they may need spinal fusion surgery, although the need for this is rare.

Spondylolysis can progress to spondylolisthesis, as shown in this image.

Anatomy of the spine

The spine has 24 vertebrae, small, rectangular bones stacked on top of each other along the length of the back. Soft intervertebral disks sit between each vertebra and provide cushioning. There is a section of the vertebra called the pars interarticularis that connects the facet joints at the back of the spine. This structure of the spine allows it to bend and twist while also stabilizing the back and protecting the spinal cord.

The pars interarticularis is vulnerable to fracture, particularly with repetitive extensions, in other words, repeatedly bending backwards as in gymnastics, for instance. With spondylolysis, the fracture may occur on one or both sides of the bone. A vertebra with stress fractures on both sides is more likely to slip out of alignment, leading to spondylolisthesis.

What causes spondylolysis and spondylolisthesis?

Repetitive stress

Most cases of spondylolysis and spondylolisthesis are repetitive stress injuries that develop during intense athletic training. Athletes who participate in sports that put repeated pressure on the lower back, such as gymnastics, rowing, diving, downhill ski racing, and weightlifting, are particularly prone to these overuse injuries of the spine. As the athlete’s muscles become overly fatigued, the load is transferred to their bones. Over time, the continued pressure can cause stress fractures in the lumbar spine.

Genetic causes

Some children are born with fragile spines that can fracture in the course of normal childhood activities. These children may have lower spine fractures by the age of 5 or 6, usually with no signs or symptoms. Typically, they are diagnosed only if their doctor orders an x-ray for another back issue.

What are the symptoms of spondylolysis and spondylolisthesis?

Spondylolysis is one of the most common causes of low back pain in young athletes. The degree of pain depends, in part, on the severity of the injury. For those with spondylolisthesis, the further a vertebra slips out of alignment, the greater the pain the child may experience (and the more likely they are to need surgery).

Symptoms of spondylolysis include:

  • low back pain that increases during physical activity
  • pain that spreads to the buttocks and down the back of the thighs
  • tight hamstrings

In addition to low back pain, other symptoms of spondylolisthesis include:

  • muscle spasms in the back of the thighs (hamstrings)
  • tight hamstrings that may force the child to walk in shorter strides
  • numbness or tingling sensations in the foot

Back pain caused by spondylolysis or spondylolisthesis tends to progress in stages, starting out mild and gradually becoming more persistent. In severe cases, the pain can become constant, even when the child is not active.

It’s important to note that low back pain is often a symptom of muscle strain, not a fracture. Either way, if your child has low back pain, they should be seen by a spine or sports medicine specialist. Prompt treatment can help resolve the pain and prevent the injury from progressing.

How we care for spondylolysis at Boston Children’s Hospital

The Spine and Sports Program at Boston Children’s Hospital focuses on spine conditions and injuries that affect young athletes. Our team includes sports medicine physicians, physical therapists, and athletic trainers who work with young athletes with a focus on recovery and safe return to play.

As part of the Orthopedic and Sports Medicine Center, we have access to an extensive network of specialists and resources that enables us to tailor treatment to each individual’s situation and needs. We collaborate regularly with colleagues throughout the hospital and The Micheli Center for Sports Injury Prevention to provide an accurate diagnosis and prompt, effective treatment for each of our patients.