Spondylolisthesis: Definition, Causes, Symptoms, and Treatment

What is Spondylolisthesis?

The spine is comprised of 33 bones, called vertebra, stacked on top of each other interspaced by discs. Spondylolisthesis is a condition where one vertebra slips forward or backwards relative to the vertebra below. More specifically, retrolisthesis is when the vertebra slips posteriorly or backwards, and anterolisthesis is when the vertebra slips anteriorly or forward.

Spondylosis vs Spondylolisthesis

Spondylosis and Spondylolisthesis are different conditions. They can be related but are not the same. Spondylosis refers to a fracture of a small bone, called the pars interarticularis, which connects the facet joint of the vertebra to the one below. This may lead to instability and ultimately slippage of the vertebra. Spondylolisthesis, on the other hand, refers to slippage of the vertebra in relation to the one below.

Types and Causes of Spondylolisthesis

There are several types of spondylolisthesis, often classified by their underlying cause:

Degenerative Spondylolisthesis

Degenerative spondylolisthesis is the most common cause, and is due to general wear and tear on the spine. Overtime, the bones and ligaments which hold the spine together may become weak and unstable.

Isthmic Spondylolisthesis

Isthmic spondylolisthesis is the result of another condition, called “spondylosis“. Spondylosis refers to a fracture of a small bone, called the pars interarticularis, which connects the facet joint of the vertebra to the one below. If this interconnecting bone is broken, it can lead to slippage of the vertebra. This can sometimes occur during childhood or adolsence but go unnoticed until adulthood when degenerative changes cause worsening slippage.

Congenital Spondylolisthesis

Congenital spondylolisthesis occurs when the bones do not form correctly during fetal development

Traumatic Spondylolisthesis

Traumatic spondylolisthesis is the result of an injury such as a motor vehicle crash

Pathologic Spondyloslisthesis

Pathologic spondylolisthesis is when other disorders weaken the points of attachment in the spine. This includes osteoporosis, tumors, or infection that affect the bones and ligaments causing them to slip.

Iatrogenic Spondylolisthesis

Iatrogenic spondylolisthesis is the result of a prior surgery. Some operations of the spine, such as a laminectomy, may lead to instability. This can cause the vertebra to slip post operatively.

Spondylolisthesis Grades

Spondylolisthesis is classified based on the degree of slippage relative to the vertebra below

• Grade 1: 1 – 25 % forward slip. This degree of slippage is usually asymptomatic.
• Grade 2: 26 – 50 % forward slip. May cause mild symptoms such as stiffness and pain in your lower back after physical activity, but it’s not severe enough to affect your everyday activities.
• Grade 3: 51 – 75 % forward slip. May cause moderate symptoms such as pain after physical activity or sitting for long periods.
• Grade 4: 76 – 99% forward slip. May cause moderate to severe symptoms.
• Grade 5: Is when the vertebra has slipped completely of the spinal column. This is a severe condition known as “spondyloptysis”.

Symptoms of Spondylolisthesis

Spondylolisthesis can cause compression of spinal nerves and in severe cases, the spinal cord. The symptoms will depend on which vertebra is affected.

Cervical Spondylolisthesis (neck)

• Neck pain
• Arm pain
• Arm numbness or tingling
• Arm weakness

Lumbar Spondylolisthesis (low back)

• Back pain
• Buttock pain
• Leg pain
• Leg numbness or tingling
• Leg weakness

Diagnosing Spondylolisthesis

Your doctor may order imaging tests to confirm the diagnosis and determine the severity of your spondylolisthesis. The most common imaging tests used include:

• X-rays: X-rays can show the alignment of the vertebrae and any signs of slippage.
• CT scan: A CT scan can provide detailed images of the bones and soft tissues in your back, allowing your doctor to see any damage or abnormalities.
• MRI: An MRI can show the spinal cord and nerves, as well as any herniated discs or other soft tissue abnormalities.

Treatments for Spondylolisthesis

Medications

For those experiencing pain, oral medications are first line treatments. This includes non-steroidal anti-inflammatory medications (NSAIDs) such as ibuprofen, acetaminophen, or in severe cases opioids or muscle relaxants (with extreme caution). Topical medications such as lidocaine patches are also sometimes used.

Physical Therapy

Physical therapy can help improve mobility and strengthen muscles around your spine to stabilize your neck and lower back. You may also receive stretching exercises to improve flexibility and balance exercises to improve coordination.

Surgery

Surgery is reserved for severe cases of spondylolisthesis in which there is a high degree of instability and symptoms of nerve compression.

In these cases a spinal fusion may be necessary. This surgery joins two or more vertebra together using rods and screws, in order to improve stability.

References

1. Alfieri A, Gazzeri R, Prell J, Röllinghoff M. The current management of lumbar spondylolisthesis. J Neurosurg Sci. 2013 Jun;57(2):103-13. PMID: 23676859.
2. Stillerman CB, Schneider JH, Gruen JP. Evaluation and management of spondylolysis and spondylolisthesis. Clin Neurosurg. 1993;40:384-415. PMID: 8111991.