Isthmic spondylolisthesis is one of the six common types of this spinal condition. This particular type is present in a child (approximately 5 to 7 years of age); however, the symptoms do not typically develop until adulthood.
Isthmic Spondylolisthesis Definition
This condition occurs in the pars interarticularis part of your spine, which is a narrow area (isthmus) between the upper and lower articular processes. Isthmic spondylolisthesis is caused by healed or unhealed stress fractures that are surrounded by fibrous tissues. It occurs when the vertebra slips forward over the lower vertebra over a period of time.
It is commonly bilateral, meaning it occurs on both sides of the vertebra. These stress fractures separate the anterior (front) of the vertebra from the neural arch, which is the curved rear section of the vertebra that encloses the canal where the spinal cord passes. Repeat fractures and cycles of healing can eventually lengthen the pars interarticularis or the fracture itself. This can lead to further displacement of the affected vertebra, which can lead to increased spinal instability.
Who’s at Risk for Isthmic Spondylolisthesis?
While anyone could potentially be at risk for this condition, there are some more than others who could develop a fracture in the pars interarticularis. Common causes include:
- Bone does not form properly
- Accumulated physical stress causing weak vertebral structures to break
- Repeated heaving lifting, stooping, or twisting
Those who participate in gymnastics, weightlifting, football, pole vaulting, or any other sport that would involve hyperextension are at a higher risk for developing this condition.
Symptoms of Isthmic Spondylolisthesis
While pain is a possibility, not everyone will experience it. However, if pain is experienced, it is typically a deep ache in the lumbar area that can occasionally radiate into the buttocks or posterior thighs.
Here are the most common symptoms that you could experience:
- Leg weakness
- Low back pain
- Muscle spasms
- Tight hamstring muscles
Symptoms may not become present until adulthood; however, those active in hyperextension sports could develop symptoms as adolescents.
Diagnosing Isthmic Spondylolisthesis
The first step in diagnosing this condition is analyzing your medical history. Your doctor will ask you questions about your symptoms, the severity of your symptoms, and the treatments you have tried to relieve these symptoms.
The next step is a physical examination. During this exam, your doctor will test for any limitations of movement, balancing issues, and pain. You will also be tested for loss of reflexes, muscle weakness, any loss of sensation, and any other signs of neurological injury.
The final step in diagnosing is diagnostic testing. Generally, the first test you will take will be an x-ray. This type of spondylolisthesis can be seen on a lateral lumbar x-ray. If more tests are needed, then your doctor may order a CT scan or MRI to get a more detailed view of your spine’s tissues.
Treating Isthmic Spondylolisthesis
Treatment will depend on the severity of the vertebral slippage. Most doctors use the Meyerding Grading System to classify. This system bases the grade on a percentage of how much one vertebral body has slipped over the vertebral body underneath.
Your doctor will take this grade into consideration along with the severity of your symptoms when determining an effective treatment plan. The majority of cases do not require surgery. Some possible treatment options could include:
- Bed rest (short term)
- Restriction of activity
- Anti-inflammatory and/or pain medication (over-the-counter or prescribed)
- Muscle relaxants
- Steroids (oral/injections)
- Physical therapy
If surgery is required for isthmic spondylolisthesis, there are different options available. Your doctor will consider the least invasive options first.