Grade 2 Spondylolisthesis at L4-5 treated by XLIF

Spondylolisthesis occurs when one vertebra slips forward over the one beneath it, most commonly in the lower back. At the L4–L5 level, this slippage can cause back pain, leg pain (sciatica), and nerve compression that affects walking and daily activities.

When conservative treatments like medication, therapy, or injections fail to provide relief, spinal fusion surgery is often recommended. Modern minimally invasive procedures—such as Extreme Lateral Interbody Fusion (XLIF)—allow surgeons to stabilize the spine through smaller incisions, less muscle disruption, and quicker recovery times.

How Common it is and Who Gets it

Degenerative spondylolisthesis is most common in adults over 50 years old, particularly in women. It often results from age-related wear and tear, arthritis, and spinal instability. The L4–L5 segment is the most frequently affected area due to its high mobility and weight-bearing function.

Causes

Spondylolisthesis develops when the joints and discs that stabilize the spine weaken, allowing one vertebra to slip forward.
Common contributing factors include:

• Disc degeneration: The intervertebral disc loses height and elasticity.
• Facet joint arthritis: The small joints in the back of the spine wear down.
• Ligament weakening: Supporting ligaments lose strength over time.
• Micro-instability: Repeated strain causes gradual forward slippage.

At the L4–L5 level, these changes can compress the spinal canal and nerves, causing symptoms such as back pain, leg numbness, and difficulty standing or walking.

How the Body Part Normally Works? (Relevant Anatomy)

The lumbar spine consists of five vertebrae (L1–L5), separated by intervertebral discs that act as cushions and allow flexibility. The facet joints stabilize the spine while permitting motion. In spondylolisthesis, the balance between these stabilizing structures is disrupted, resulting in vertebral misalignment and nerve irritation.

What You Might Feel – Symptoms (Clinical Presentation)

Typical symptoms of spondylolisthesis include:

• Chronic lower back pain
• Pain radiating into one or both legs (sciatica)
• Numbness or tingling in the legs or feet
• Weakness or fatigue while walking
• Difficulty standing upright
• Pain relief when sitting or bending forward
  In severe cases, nerve compression may cause loss of bladder or bowel control (cauda equina syndrome), which requires immediate medical attention.

How Doctors Find the Problem? (Diagnosis and Imaging)

Diagnosis begins with a detailed clinical examination followed by imaging studies:

• X-rays: Identify vertebral slippage and help classify the degree of movement.
• MRI: Evaluates soft tissues and nerve compression.
• CT scans: Provide detailed bone images, especially useful for surgical planning.
• Flexion-extension X-rays: Assess spinal instability.

The degree of slippage is measured using the Meyerding classification, ranging from Grade I (mild) to Grade IV (severe).

Classification

Spondylolisthesis is categorized by cause and severity:

• Degenerative: Age-related wear and tear.
• Isthmic: Due to a small fracture (spondylolysis) in the bone connecting the joints.
• Congenital: Present at birth from spinal malformation.
• Traumatic or pathological: Due to injury, tumor, or bone disease.
  By grade:
• Grade I: <25% slip
• Grade II: 25–50% slip
• Grade III: 50–75% slip
• Grade IV: >75% slip

Other Problems That Can Feel Similar (Differential Diagnosis)

Conditions with similar symptoms include:

• Lumbar disc herniation
• Spinal stenosis
• Degenerative disc disease
• Facet joint arthritis
• Piriformis syndrome

Treatment Options

Non-Surgical Care

Mild cases are initially managed conservatively:

• Medications: NSAIDs, pain relievers, or muscle relaxants.
• Physical therapy: Core-strengthening and posture training.
• Epidural steroid injections: Reduce inflammation and nerve irritation.
• Bracing: May help in younger or athletic patients.

If symptoms persist or progress, surgical intervention may be required.

Surgical Care – Extreme Lateral Interbody Fusion (XLIF)

XLIF is a minimally invasive fusion technique performed through the patient’s side rather than the back or abdomen.
Steps of the procedure include:

1. Making a small incision on the side of the abdomen.
2. Using a tubular retractor to access the spine through the psoas muscle.
3. Removing the damaged disc and placing a spacer filled with bone graft between the vertebrae.
4. Inserting screws and rods for stabilization.

Benefits of XLIF:

• Smaller incisions and less blood loss.
• Shorter hospital stay (typically 1–2 days).
• Faster recovery and less postoperative pain.
• Lower infection risk compared to open fusion.

Recovery and What to Expect After Treatment

• Immediate postoperative period: Most patients walk within 24 hours.
• Hospital stay: Usually 1–2 days.
• Return to activity: Light activity within weeks; full recovery in 3–6 months.
• Physical therapy: Begins early to improve strength and flexibility.

Most patients report significant pain relief and improved stability within weeks.

Possible Risks or Side Effects (Complications)

Potential risks include:

• Thigh numbness or hip flexor weakness: Usually temporary from psoas muscle retraction.
• Nerve irritation: Rare with real-time monitoring.
• Infection or bleeding: Very uncommon with minimally invasive techniques.
• Non-union (failed fusion): Occurs rarely if bone healing is incomplete.

Long-Term Outlook (Prognosis)

Studies show excellent outcomes for patients undergoing XLIF for L4–L5 spondylolisthesis.

• Over 90% of patients experience lasting pain relief.
• Radiographic imaging after one year typically shows solid fusion with restored alignment.
• Age, BMI, or previous surgeries do not significantly affect success rates.

Insurance & Cost

We work with all major insurance carriers (Aetna, Anthem BCBS, Cigna, Empire BCBS, UnitedHealthcare), as well as Medicare, most workers’ compensation and no-fault insurance plans. Your out-of-pocket cost depends on your insurance benefits.

Call our billing team at (631) 981-2663 before scheduling to verify your coverage and discuss expected out-of-pocket costs. For the full list of carriers we accept and patient billing protections, see our Insurance Information page.

Summary and Takeaway

Spondylolisthesis at L4–L5 is a common cause of lower back and leg pain due to vertebral slippage. When conservative care fails, Extreme Lateral Interbody Fusion (XLIF) provides a minimally invasive, safe, and effective solution. It offers excellent pain relief, restores spinal alignment, and helps patients return quickly to active lifestyles with fewer complications and shorter hospital stays than traditional open surgery.