Spondylolysis: Definition, Signs, Symptoms, Causes, Risk Factors, Pathophysiology, Diagnosis and Treatment

It is defined as a defect or stress fracture in the interarticular pair of the vertebral arch.

Most cases occur in the lower lumbar vertebrae (L5), but spondylolysis can also occur in the cervical vertebrae. The fracture can happen on both sides or only one side of the bone.

Spondylolysis is a fracture due to cracking or stress in one vertebra, the small bones that make up the spine.

The injury occurs most frequently in children and adolescents who participate in sports that involve repeated stress on the lower back, such as gymnastics, soccer, and weightlifting.

In some cases, the stress fracture weakens the bone so much that it can not maintain its proper position in the spine, and the vertebra begins to move or slide out of place. This condition is called spondylolisthesis.

For most patients with spondylolysis, back pain and other symptoms will improve with conservative treatment. This always begins with a period of rest from sports and other strenuous activities.

However, patients with persistent back pain or severe slippage of a vertebra may need surgery to relieve their symptoms and allow them to return to sports and activities.


Signs and symptoms of spondylolysis

In most cases, spondylolysis occurs asymptomatically, making the diagnosis difficult and incidental. When a patient has symptoms, there are general signs and symptoms that a doctor will look for:

Clinical signs:

  • Pain when completing the stork test (placed in hyperextension and rotation).
  • Excessive lordotic posture.
  • Unilateral sensitivity to palpation.
  • Visible in diagnostic images (Scottie dog fracture).


  • Unilateral lumbar pain.
  • Pain that is transmitted to the legs or buttocks.
  • The onset of pain can be acute or gradual.
  • Pain that can restrict daily activities.
  • Pain that aggravates later strenuous action.
  • Aggravated pain with lumbar hyperextension.


The cause of spondylolysis remains unknown. However, it is believed that many factors contribute to its development. The condition is present in up to 6% of the population, most of which occur asymptomatically.

The research supports that hereditary and acquired risk factors can make one more susceptible to the defect.

The disorder is generally more prevalent in men than women and tends to occur earlier in men due to their involvement in more strenuous activities at a younger age.

In a young athlete, the spine is still growing, which means that many ossification centers leave points of weakness in the spine.

This leaves young athletes at greater risk, particularly when they are involved in repetitive hyperextension and rotation through the lumbar spine.

Spondylolysis is a common cause of low back pain in preadolescents and adolescent athletes since it represents around 50% of all lumbar pain.

It is believed that repetitive trauma and inherent genetic weakness can make an individual more susceptible to spondylolysis.

Risk factor’s

Sports that involve repetitive or forced hyperextension of the spine, especially when combined with rotation, are the primary mechanism of injury for spondylolysis.

The stress fracture of the interarticular pair occurs on the opposite side of the activity. For example, for a right-handed player, the fracture occurs on the left side of the vertebra. Spondylolysis has a greater incidence in the following activities:

  • Baseball.
  • Tennis.
  • Diving.
  • Cheerleaders.
  • Gymnastics.
  • Football.
  • Fight.
  • Weightlifting.
  • Cricket.
  • Pole vault.
  • Rugby.
  • Volleyball.
  • Ballet.

Although this condition may be caused by repetitive trauma to the lumbar spine in strenuous sports, other risk factors may also predispose individuals to spondylolysis.

Men are more commonly affected by spondylolysis than women. A study that analyzed juvenile athletes found that the average age of individuals with spondylolisthesis was 20 years.

Spondylolysis is also shown in families that indicate a hereditary component, such as a tendency to more fragile vertebrae.

Pathophysiology of spondylolysis

Spondylolysis is a bone defect or fracture within the interarticular portion of the vertebral arch in the spine. The vast majority of spondylolysis occurs in the lumbar vertebrae. However, it can also be seen in the cervical vertebrae.

The lumbar vertebra consists of a body, pedicle, lamina, interarticular pairs, transverse process, spinous process, and upper and lower articular facets, forming joints that join the vertebrae.

When examining the vertebra, the interarticular pair is the bony segment between the superior and inferior articular facet joints in front of the lamina and behind the pedicle.

The separation of the pars interarticular occurs when the spondylolysis is present in the spine.

Spondylolysis is usually caused by a stress fracture of the bone and is especially common in adolescents who are over-trained in activities.

The interarticular pair is vulnerable to fracture during spinal hyperextension, especially when combined with rotation or when a force is experienced during a landing.

This stress fracture most commonly occurs when the concave lumbar spine transitions to the convex sacrum (L5-S1). A significant number of individuals with spondylolysis will develop spondylolisthesis, which is valid for 50-81% of this population.


There are several imaging techniques used to diagnose spondylolysis. Standard imaging techniques include X-rays, magnetic resonance imaging, bone scintigraphy (bone scan), and computed tomography (CT scan).

Qualified health professionals can also perform clinical tests such as the one-leg hyperextension test to diagnose active spondylolysis.

Physical exam

Your doctor will start by taking a medical history and asking about your usual health and the signs and symptoms of the patient. He or she will want to know if the patient participates in sports.

Patients who participate in sports that exert excessive stress on the lower back are more likely to have a diagnosis of spondylolysis or spondylolisthesis.

The attending physician will scrupulously examine the patient’s back and spine, looking for:

  • Areas where sensitivity is present.
  • A range of restricted or limited movement.
  • Muscular tremors
  • Muscular weakness.

Your doctor will also observe the patient’s posture and gait (how he walks). In some cases, tight hamstrings can cause a patient to stand awkwardly or walk stiffly.

Hyperextension test with one leg

This is a test performed by a qualified healthcare professional within a clinical setting. It involves the patient standing on one leg and then leaning back.

The test should produce pain on the same spine side as the leg on which it is standing. If it causes pain, this indicates spondylolysis on that side. The test is performed on the other side, re-evaluating the pain.

The test can be positive on the one hand, on both sides, or either side. Imaging tests will help confirm the diagnosis of spondylolysis or spondylolisthesis.

Bone scan

X-rays (electromagnetic radiation) are projected through the body to produce an image of its internal structures.

Radiation is more attenuated (absorbed) by the denser tissues of the body (i.e., bone) than softer tissues (i.e., muscles, organs, etc.), creating a composite image of shades of gray ranging from white to the black.

A vertebra with a fracture or defect of the pars interarticularis will have a dark mark through this region of the bone.

As this is difficult to see in the anterior radiograph, an oblique x-ray of the lumbar spine can usually identify spondylolysis.

If it is inconclusive, a new CT scan can produce three-dimensional images to show the defect more clearly. However, the examination raises the patient’s radiation dose by at least an order of magnitude than simple x-rays.

Bone scintigraphy

Also known as a bone scan, a bone scan involves injecting a small amount of a radioactive tracer into the bloodstream. This tracer decomposes and emits radioactive energy detected by a special camera.

The camera produces a black and white image where areas that are shown as dark black indicate bone damage of some kind.

If there is a black spot on the lumbar vertebrae (for example, L5), this indicates damage and potentially spondylolysis. Computerized tomography is usually ordered to confirm the spondylolysis if this test is positive.

Computed tomography

Commonly known as computed tomography or computerized tomography scanning, this form of imaging is very similar to X-ray technology but produces many more images than an x-ray.

Multiple images produce cross-sectional views that are not possible with an x-ray. This allows a doctor or radiologist to examine images from more angles than an x-ray.

For this reason, computed tomography is much more accurate for detecting spondylolysis than an x-ray. Bone scintigraphy combined with computed tomography is considered the gold standard, meaning it is better to detect spondylolysis.

Magnetic resonance image

Magnetic resonance imaging is a newer technique used to diagnose spondylolysis and is favorable for some reasons. Magnetic Resonance is much more accurate than radiography and does not use radiation.

The magnetic resonance image uses powerful magnets and radio frequencies to produce detailed images of many different tissue densities, including bone and soft tissue.


The treatment objectives for spondylolysis are:

  • Reduce pain
  • Allow a fracture of recent pairs to heal.
  • Return the patient to sports and other daily activities.

Nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen can help reduce swelling and relieve back pain.

Conservative treatment

The treatment for spondylolysis includes bracing, restriction of activity, extension exercises, flexion exercises, and deep abdominal strengthening, which is administered through physiotherapy.

The duration of physical therapy a patient receives varies according to the severity of the spondylolysis. However, it typically varies from three to six months. Physical therapy aims to minimize movement in the dangerous defect of the pars interarticularis.

Once the patient completes the physical therapy and has no symptoms or inflammation in the lower back, he is authorized to continue with his daily or athletic activities.

However, a patient may need to maintain a variety of rehabilitation techniques after physiotherapy to prevent spondylolysis recurrence.

Deep abdominal contraction exercises

Deep abdominal co-contraction exercises aim to train the muscles surrounding the lumbar spine that provide stability to the spine.

Spondylolysis produces spinal instability and interrupts co-recruitment patterns among muscle synergies. Specifically, the local muscles that attach directly to the spine are affected.

The lumbar multiforme and transversus abdominis play a direct role in stabilizing the lumbar spine.

In contrast, the local muscles of people with spondylolysis are vulnerable to dysfunction, which results in abnormal spinal stability that causes chronic low back pain.

To compensate, the enormous torque produced by the global muscles is used to stabilize the spine.

In one study, patients are taught how to train the contraction of the deep abdominal muscles and the lumbar multifidus in static postures, functional tasks, and aerobic activities.

This technique reduces pain and functional disability compared to other conservative treatments. These results also had a long-term effect in reducing pain and functional disability levels.

This is because motor programming eventually became automatic, and conscious control was no longer needed to contract the deep abdominal muscles during activities.

Activity restriction

It is advisable to restrict the activity of spondylolysis for a short period once the patient becomes symptomatic, followed by a guided physical therapy program.

Avoiding sports and other activities that exert excessive stress on the lower back for some time can often help improve back pain and other symptoms.

Once the spondylolysis has been diagnosed, the treatment often consists of a short rest period of two or three days, followed by a physiotherapy program.

There must be restrictions on lifting heavy things, excessive push-ups, twisting, and avoiding any work, recreational activities, or participation in sports that cause stress in the lumbar spine.

Activity restriction can help eliminate and control the patient’s symptoms to resume normal activities. Activity restriction is used more frequently along with other rehabilitation techniques, including bracing.


Acute spondylolysis is often treated using an antilordotic brace (Boston orthopedic brace) to control and limit spinal movement and reduce stress in the injured spinal segment.

The bracing immobilizes the spine in a flexed position for a short period to allow healing of the bony defect in the pars interarticularis.

An antilordotic brace commonly uses a contoured plastic component to better adapt to the body.

The antilordotic reinforcement subsequently reduces the symptoms of the athlete by decreasing the stress in the lower back and allows a quick return to the sport for the athletes. In general, reinforcement is used for 6-12 weeks.

For a corset to be effective, it must be worn every day for the required time. Patients receive a reinforcement schedule determined by their physiotherapist that explains how much time the device should be used daily.

The effectiveness of a corset increases with compliance with the reinforcement schedule. Patients who do not follow their reinforcement schedule are more likely to have their symptoms progress.

Research has shown that when orthotics are used as prescribed with full compliance, they are successful in preventing the progression of spondylolysis.


Most patients with spondylolysis do not require surgery. However, if the symptoms are not relieved by non-surgical treatments or when the condition progresses to high-grade spondylolisthesis, then patients may require surgery.

Surgery may be recommended for patients with spondylolysis who have:

  • Severe or high-grade curvature.
  • Curvature that progressively worsens.
  • Back pain that has not improved after a period of non-surgical treatment.

The spinal fusion between the fifth lumbar vertebra and the sacrum is the surgical procedure most commonly used to treat patients with spondylolisthesis. The objectives of spinal fusion are:

  • Prevent further progression of the curvature.
  • Stabilize the spine.
  • Significantly relieve back pain.

There are two main types of surgery for this condition:

Spinal fusion: This procedure is recommended when a set of vertebrae becomes loose or becomes unstable. The surgeon joins two or more bones (vertebrae) through metal bars, screws, and bone grafts.

Bone grafts complete their fusion 4-8 months after surgery, ensuring the spine is in the correct position.

The procedure is also used to treat spinal instability, fractures in the lumbar spine, and severe degenerative disc disease. The process is relatively non-invasive, is performed through small incisions, and has a high success rate.

Laminectomy: often performed when spinal stenosis occurs along with spondylolysis. The procedure surgically removes part or all of the lamina of the osseous ring of the vertebra to reduce the pressure on the spinal cord.

Laminectomy is commonly performed on the vertebrae in the lower back and neck.

Implications for rehabilitation

Spondylolysis can have a significant impact on a young athlete’s career and may impede his future ability to perform. It is essential to understand how social and psychological factors can affect the rehabilitation of an injured athlete.

Frustration, anger, confusion, fear, and depression are some psychological factors experienced by injured athletes. Therefore, a debilitating injury can have a significant impact on the mental well-being of an athlete.

These psychological factors can also affect recovery and return to sports, as fear of a new injury often prevents athletes from adhering to rehabilitation and returning to their sport with maximum intensity.

Social factors can also affect injuries’ cognitive, behavioral, and physical responses. More specifically, the social isolation of the team can have a profound psychological effect.

This makes it essential to provide social support through listening support, emotional support, personal assistance, and the shaping of reality.

Educating the athletes about the rehabilitation process is essential, so they know what to expect. For example, explain what activities to avoid and cause pain, as well as the duration of the treatment process.

In addition, it is essential to select the correct treatment option for each individual. For conservative methods, adherence to exercise requires motivated patients, as it can be tedious and time-consuming.

For example, a study that analyzed deep abdominal co-contraction reported that it could take between 4 and 5 weeks to achieve this co-contraction pattern.