Spondylolisthesis is one of the most common conditions evaluated by spine surgeons — and one of the most commonly misunderstood. Patients are often told they have a “slipped disc” when what they actually have is a slipped vertebra. The two conditions are different, their symptoms overlap in important ways, and the treatment decisions are not always straightforward. Here is what spondylolisthesis is, why it causes symptoms, and when surgery is and is not the right answer.
What Is Spondylolisthesis?
Spondylolisthesis is the forward displacement of one vertebra over the vertebra below it. The word comes from the Greek spondylos (vertebra) and olisthesis (slipping). It is graded by severity using the Meyerding classification, from Grade I (less than 25% slip) to Grade IV (greater than 75% slip), with Grade V (spondyloptosis) reserved for complete dislocation.
The most common location is the lower lumbar spine, particularly L4–L5 and L5–S1. There are several types, each with a different underlying cause:
- Degenerative spondylolisthesis — the most common type in adults; occurs when the disc and facet joints degenerate and lose their ability to restrain normal motion, allowing one vertebra to slip forward on the one below; most common at L4–L5 and more prevalent in women and older adults
- Isthmic spondylolisthesis — caused by a stress fracture (spondylolysis) of the pars interarticularis, a small bridge of bone in the posterior arch; common in young athletes, particularly gymnasts, football linemen, and weightlifters; the fracture allows the vertebra to slip forward; most common at L5-S1
- Congenital spondylolisthesis — due to abnormal development of the posterior spinal elements at birth; less common
- Iatrogenic or postoperative spondylolisthesis — can develop after laminectomy or other posterior surgery that destabilizes the spinal segment
What Symptoms Does It Cause?
Many people have spondylolisthesis and never know it — the slip is discovered incidentally on imaging obtained for another reason. Whether spondylolisthesis causes symptoms depends on the degree of slip, the presence of stenosis, the stability of the segment, and individual factors including age and activity level.
When it does cause symptoms, the most common presentations include:
- Lower back pain — often worse with activity, prolonged standing, or extension (bending backward); typically relieved by sitting or flexion
- Leg pain, numbness, or weakness — caused by nerve root compression from the slipped vertebra narrowing the neural foramen or from associated stenosis of the spinal canal; may mimic sciatica
- Neurogenic claudication — leg symptoms that worsen with walking or standing and improve with sitting or leaning forward; a hallmark of lumbar stenosis that accompanies many degenerative spondylolisthesis cases
- Hamstring tightness — particularly in younger patients with isthmic spondylolisthesis; a classic but often overlooked finding
- Visible postural change — in high-grade slips, patients may develop a characteristic crouched posture or altered gait
When Is Non-Surgical Treatment Appropriate?
The majority of patients with spondylolisthesis — including those with significant symptoms — can be managed successfully without surgery. Non-surgical treatment is the appropriate first step for most patients and may include:
- Physical therapy — core strengthening, postural training, and flexion-based exercises can significantly reduce symptoms and improve function in many patients; this is the most important non-surgical intervention
- Activity modification — avoiding activities that aggravate symptoms while maintaining general fitness
- Anti-inflammatory medications — NSAIDs can help manage pain flares
- Epidural steroid injections — can provide meaningful, though typically temporary, relief of leg pain from nerve compression; most useful as a bridge to physical therapy or while awaiting surgical planning
- Bracing — particularly in adolescents with isthmic spondylolysis or low-grade spondylolisthesis; bracing during the acute phase can allow the stress fracture to heal
An important point: the degree of slip on imaging does not directly predict the severity of symptoms or the need for surgery. A Grade II slip in one patient may cause debilitating symptoms; the same grade in another patient may cause none. Treatment decisions are driven by symptoms and function, not imaging findings alone.
When Is Surgery Indicated?
Surgery for spondylolisthesis is recommended when:
- Conservative treatment has failed — typically after 3 to 6 months of appropriate non-surgical management without adequate improvement in symptoms and function
- Progressive neurological deficit — worsening leg weakness, foot drop, or loss of bladder or bowel control warrant urgent or expedited surgical evaluation regardless of how long conservative treatment has been tried
- Severe or intractable pain — pain that significantly impairs quality of life and does not respond to non-surgical measures
- High-grade slip — Grade III or IV slips are generally unstable and carry a higher risk of neurological compromise; surgery is more frequently recommended even in the absence of severe symptoms
- Progressive slip — documented worsening of the degree of displacement on serial imaging, particularly in adolescents with isthmic spondylolisthesis
What Does Surgery Involve?
Surgery for spondylolisthesis typically involves two goals: decompression of the compressed nerve roots and stabilization (fusion) of the unstable segment. The specific procedure depends on the type and grade of spondylolisthesis, the degree of stenosis, the patient’s anatomy, and other factors.
Common surgical approaches include:
- Posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) — the most common approaches; decompression is performed from the back, an interbody cage is placed in the disc space for stability and fusion, and pedicle screws and rods complete the construct
- Minimally invasive TLIF (MIS-TLIF) — for selected patients, the same procedure can be performed through smaller incisions with less muscle disruption
- Anterior lumbar interbody fusion (ALIF) — an anterior approach may be used alone or in combination with posterior fixation for selected cases, particularly when greater disc height restoration or lordosis correction is needed
- Reduction of the slip — in high-grade spondylolisthesis, partial reduction of the vertebral displacement before fusion may be performed to improve alignment and neural decompression; this is technically demanding surgery that requires specific expertise
Dr. Sardar uses robotic-assisted navigation and intraoperative neuromonitoring as standard for all spondylolisthesis fusions, providing enhanced screw accuracy and real-time feedback on nerve function throughout the procedure.
What to Expect from Surgery
Surgery for spondylolisthesis, when performed in appropriately selected patients, reliably improves leg pain and neurological symptoms. Back pain improvement is meaningful in most patients, though complete elimination of all back pain is not guaranteed. The landmark SPORT trial — one of the largest surgical trials in spine surgery — demonstrated significant and durable advantages of surgery over non-operative care for symptomatic degenerative spondylolisthesis at 4-year follow-up.
Recovery from a single-level lumbar fusion for spondylolisthesis typically involves a hospital stay of 1 to 3 days, return to light activity within 4 to 6 weeks, and return to most normal activities within 3 to 4 months. Full fusion maturation takes 12 months.
About Dr. Zeeshan Sardar
Dr. Sardar is Co-Chief of Spinal Deformity Surgery at NewYork-Presbyterian / Columbia University and treats the full spectrum of lumbar spine conditions including spondylolisthesis, stenosis, disc herniation, and complex deformity. To schedule a consultation, call 212-932-5187 or visit the contact page.
This article is for educational purposes only and does not constitute individualized medical advice. Please consult a qualified spine specialist to discuss your specific condition.