Spondylolysis

Overview

Spondylolysis is a defect or stress fracture in the pars interarticularis, a thin bridge of bone that connects the upper and lower joints of a vertebra. It most commonly affects the fifth lumbar vertebra (L5) in the lower back. The condition is one of the most frequent causes of persistent low back pain in children and adolescents, particularly those who play sports that involve repeated bending and twisting of the spine.

Many people with spondylolysis have no symptoms and never know they have it. When pain does occur, the outlook is generally good: most cases improve with rest, activity changes, and physical therapy. In some people the weakened vertebra can slip forward over time, a related condition called spondylolisthesis.

Symptoms

When spondylolysis causes symptoms, the main complaint is low back pain. The pain is often mild to moderate and tends to follow a recognizable pattern.

• Lower back pain that worsens with activity, especially bending backward
• Pain that eases with rest
• Stiffness in the lower back and tight hamstring muscles
• Discomfort that may spread into the buttocks or upper thighs
• Pain that flares during or after sports such as gymnastics, football, diving, or weightlifting

Spondylolysis rarely causes leg numbness, tingling, or weakness on its own. If these nerve-related symptoms appear, it may signal that a vertebra has slipped or that a nerve is being pinched, and this should be evaluated by a doctor.

Causes

Spondylolysis is usually an overuse injury rather than the result of a single accident. Repeated stress on the lower spine causes a small crack to form in the pars interarticularis, much like a stress fracture in a leg bone from running.

• Repetitive hyperextension: Sports and activities that involve arching the back backward again and again place strain on the pars.
• Growth spurts: Rapid growth in adolescence, when bones are still developing, increases vulnerability.
• Genetic tendency: Some people are born with thinner or weaker bone in this area, making fracture more likely.

In a minority of people the defect is present from birth. A sudden, severe injury can occasionally fracture the pars, but most cases build up gradually over months or years of activity.

Risk Factors

• Adolescence and active participation in sports
• Activities involving repeated back arching, such as gymnastics, dance, diving, cricket fast bowling, and football
• Rapid growth spurts
• A family history of spondylolysis or spondylolisthesis
• Pre-existing differences in the shape of the lower spine

Diagnosis

A doctor begins with a physical examination, checking how back pain changes with bending forward and backward and testing flexibility and nerve function. Imaging confirms the diagnosis.

• X-rays: Often the first test and can show a clear pars defect, though early stress fractures may not appear.
• MRI: Detects early bone stress and inflammation before a full fracture forms, without radiation, and is often preferred for young patients.
• CT scan: Gives detailed images of bone and can show whether a fracture is recent or old.

Treatment

The large majority of people with spondylolysis recover with non-surgical care aimed at letting the bone heal and strengthening the muscles that support the spine.

• Rest from aggravating activity: A break from the sport or movements that cause pain, often for several weeks to a few months.
• Physical therapy: Exercises to build core and back strength, improve posture, and stretch tight hamstrings.
• Pain relief: Over-the-counter medicines and ice can ease discomfort during flare-ups.
• Bracing: A back brace is sometimes used to limit motion and support healing.

A gradual, supervised return to activity follows once pain settles. Surgery is uncommon and is generally reserved for people with severe, ongoing pain that does not improve with months of conservative treatment, or where a vertebra has slipped significantly.

Prevention

• Warm up and stretch before sports, especially the hamstrings and core
• Build core strength to support the lower spine
• Use proper technique in activities that involve back arching
• Avoid sudden large increases in training intensity or volume
• Take rest days and report persistent back pain early rather than playing through it

When to See a Doctor

See a doctor if a child, teenager, or adult athlete has low back pain that lasts more than a couple of weeks, keeps returning, or limits activity. Seek prompt medical attention if back pain is accompanied by:

• Numbness, tingling, or weakness in the legs
• Pain that radiates down a leg
• Changes in bladder or bowel control, which require urgent evaluation
• Pain following a significant injury or fall

Related Topics

Frequently Asked Questions

References

1. American Academy of Orthopaedic Surgeons (AAOS). Spondylolysis and Spondylolisthesis.
2. Mayo Clinic. Spondylolisthesis and spondylolysis.
3. MedlinePlus, U.S. National Library of Medicine. Spondylolysis.