Spondylolisthesis occurs when one vertebra slips forward over the vertebra below it, causing spinal misalignment. This slippage can narrow the spinal canal, compress nerve roots, and cause pain, stiffness, and neurological symptoms. It most commonly affects the lower lumbar spine, particularly at the L4–L5 and L5–S1 levels.
Spondylolisthesis develops from underlying structural or degenerative spinal conditions. In younger patients it is most often caused by a Pars Defect (isthmic type), while in older adults it is driven by Facet Disease and Degenerative Disc Disease. The forward slip progressively narrows the spinal canal, making spondylolisthesis a leading cause of Spinal Stenosis and Foraminal Stenosis in the lumbar spine.
Causes
Degenerative and structural causes.
The most common type in adults is degenerative spondylolisthesis, in which age-related breakdown of the facet joints and intervertebral discs allows one vertebra to gradually slip forward. In younger patients, isthmic spondylolisthesis results from a stress fracture (pars defect) that allows the vertebra to shift.
Other causes
Less commonly, spondylolisthesis can be caused by congenital spinal abnormalities, traumatic fractures, spinal tumors, or pathologic bone weakening from conditions such as osteoporosis. High-impact sports involving repetitive hyperextension — such as gymnastics, football, and weightlifting — increase risk in young athletes.
Symptoms
Many cases are asymptomatic and discovered incidentally. When symptomatic, patients typically report lower back pain and stiffness that worsens with activity and improves with rest. Nerve compression from the slippage can cause sciatica-like pain, numbness, or weakness radiating into the legs. Severe cases may cause neurogenic claudication or, rarely, bowel and bladder dysfunction requiring urgent evaluation — see Cauda Equina Syndrome.
Diagnosis
Physical examination assesses lumbar range of motion, neurological function, and signs of nerve root irritation. Standing X-rays — including lateral and flexion-extension views — are essential for measuring the degree of slippage and detecting instability.
A lumbar spine MRI evaluates the spinal canal, intervertebral discs, nerve root compression, and soft tissue involvement. CT scan provides detailed bony anatomy, particularly useful for identifying associated pars defects.
Slip Grade Classification
Spondylolisthesis severity is graded using the Meyerding classification based on the percentage of forward slippage of one vertebra relative to the one below.
- Grade I: 0–25% forward slip — often asymptomatic and managed conservatively.
- Grade II: 26–50% forward slip — may cause significant pain and nerve compression.
- Grade III: 51–75% forward slip — associated with more significant deformity and symptoms.
- Grade IV: 76–100% forward slip — severe deformity often requiring surgical intervention.
- Grade V (Spondyloptosis): Greater than 100% slip — complete dislocation of the vertebra.
Treatments
Treatment depends on the grade of slippage, symptom severity, and the presence of neurological compromise. The majority of low-grade cases respond well to conservative management.
Activity modification — avoiding high-impact or extension-based activities — combined with core strengthening and physical therapy is the foundation of non-surgical care.
Conservative treatment: Physical therapy focusing on lumbar stabilization, NSAIDs for pain and inflammation, and epidural steroid injections for nerve-related symptoms are standard first-line approaches. Bracing may be recommended for younger patients or those with acute instability.
Surgical treatment
Surgery is considered when conservative measures fail, when there is progressive slippage, or when neurological deficits are present. The standard surgical procedure is spinal decompression combined with instrumented fusion — stabilizing the slipped vertebra with screws and rods and fusing it to the adjacent level to prevent further movement. Minimally invasive techniques may be appropriate for selected Grade I and II cases.
Related Spine Conditions
- Pars Defect
- Facet Disease
- Degenerative Disc Disease
- Spinal Stenosis
- Foraminal Stenosis
- Back to all Spine Conditions
Get an MRI to Confirm Your Diagnosis
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