Spondylolisthesis
Spondylolisthesis is a condition in which one vertebra slips forward—or less commonly backward—relative to the vertebra below it. It can occur at any level of the spine but is most common in the lower lumbar region. Spondylolisthesis may result from age-related degeneration, stress-related defects in the vertebra, trauma, or other structural abnormalities. Many people with spondylolisthesis have no symptoms, while others develop lower back pain, leg pain, or symptoms related to nerve compression.
What is it?
The spine is made up of stacked vertebrae separated by discs and stabilized by ligaments and facet joints. In spondylolisthesis, this alignment becomes disrupted so that one vertebra slips forward (anterolisthesis) or, less commonly, backward (retrolisthesis) relative to the vertebra beneath it.
The severity of slippage is commonly graded from I to IV based on the percentage of vertebral displacement, with grade I representing mild slippage and grade IV representing severe slippage.
There are several forms of spondylolisthesis.
Degenerative spondylolisthesis is the most common type and develops from age-related degeneration of the discs and facet joints that gradually allows vertebral instability and slippage. It most commonly affects the L4–L5 level in adults over age 50.
Isthmic spondylolisthesis develops from a defect or stress fracture in a portion of the vertebra called the pars interarticularis. This form is often associated with repetitive hyperextension activities during adolescence and most commonly affects the L5–S1 level.
Less common forms include congenital spondylolisthesis, traumatic spondylolisthesis, pathologic spondylolisthesis related to tumors or metabolic bone disease, and post-surgical instability.
Symptoms vary depending on the degree of slippage, spinal level involved, and whether nearby nerves become compressed.
Many individuals are asymptomatic and discover the condition incidentally on imaging studies. Others may experience chronic lower back pain, stiffness, hamstring tightness, muscle spasms, or pain radiating into the buttocks or legs.
When slippage contributes to spinal canal narrowing or neural foraminal stenosis, symptoms of radiculopathy or neurogenic claudication may develop. These can include sciatica, numbness, tingling, leg weakness, heaviness in the legs while walking, or symptoms that improve with sitting or bending forward.
X-rays of the spine are commonly the first imaging test used because they clearly show vertebral alignment and slippage. Flexion-extension views may help identify spinal instability.
MRI of the spine is the preferred imaging test for evaluating associated disc degeneration, nerve compression, spinal stenosis, ligament changes, and inflammation involving the surrounding soft tissues.
CT imaging may be used for more detailed evaluation of bony anatomy, particularly when pars defects or fractures are suspected.
Important to Know
Most cases of spondylolisthesis are treated conservatively without surgery.
Treatment often includes physical therapy focused on core strengthening and stabilization, posture correction, ergonomic modifications, activity modification, weight management, and anti-inflammatory medications.
Image-guided spinal injections may help reduce inflammation and pain in selected patients.
Surgery is generally reserved for patients with persistent disabling pain, progressive neurological symptoms, spinal instability, severe nerve compression, or worsening slippage despite conservative management.
Because spondylolisthesis frequently coexists with degenerative disc disease, facet arthropathy, spinal stenosis, and neural foraminal stenosis, imaging findings are interpreted together with symptoms and neurological examination findings rather than in isolation.
Maintaining core strength, flexibility, proper lifting mechanics, and a healthy body weight may help reduce stress on the spine and improve long-term spinal stability.
Follow-up imaging may be recommended when symptoms progress or when surgical or interventional treatment is being considered.
Red flag symptoms include sudden severe weakness, progressive numbness, gait or balance difficulty, loss of bowel or bladder control, numbness in the groin or inner thighs, unexplained weight loss, fever with back pain, or severe pain after trauma. These symptoms require urgent medical evaluation because they may indicate severe nerve compression or another serious spinal condition.