What is the treatment for anterolisthesis (anterior vertebral slippage)?

Treatment of Anterolisthesis

For anterolisthesis with stenosis and instability, decompression combined with instrumented fusion provides superior outcomes (96% excellent/good results) compared to decompression alone (44%), while isolated anterolisthesis without stenosis or neurological symptoms should be managed conservatively with structured physical therapy. 1, 2

Conservative Management: First-Line Treatment

Conservative treatment is mandatory for at least 6 weeks to 3 months before considering surgical intervention. 1

• Formal supervised physical therapy programs focusing on core stabilization, lumbar spine strengthening, and flexibility exercises form the foundation of conservative care 1, 3
• Neuroleptic medications (gabapentin or pregabalin) should be trialed for radicular symptoms if present 1
• Anti-inflammatory medications and epidural steroid injections provide short-term relief (typically less than 2 weeks) for radiculopathy but have limited evidence for isolated axial back pain 1
• Facet joint injections can be both diagnostic and therapeutic, as facet-mediated pain causes 9-42% of chronic low back pain in degenerative disease 1
• Chiropractic manipulation and corrective exercises have shown promise in case reports for reducing vertebral slippage, though this requires further research validation 4

A critical pitfall is proceeding to surgery without documented completion of comprehensive conservative management, which includes formal physical therapy—not just home exercises. 1

Surgical Indications: When Conservative Treatment Fails

Absolute Indications for Fusion with Decompression

Fusion is specifically recommended when anterolisthesis occurs with any of the following: 5, 1, 2

• Documented spondylolisthesis of any grade with corresponding stenosis and failed conservative management 1, 2
• Radiographic instability on flexion-extension films (>3-4mm translation or >10-15 degrees angulation) 5, 6
• Severe stenosis requiring extensive decompression (>50% facetectomy) that will create iatrogenic instability 5, 2
• Neurological compromise with imaging-confirmed nerve root or spinal cord compression at the corresponding level 1, 2
• Degenerative spondylolisthesis with neurogenic claudication refractory to 3-6 months of conservative care 1, 2

Evidence Supporting Fusion Over Decompression Alone

Class II medical evidence demonstrates that patients with stenosis AND spondylolisthesis achieve statistically significantly better outcomes with fusion: 1, 2

• 96% report excellent/good results with decompression plus fusion versus 44% with decompression alone 1, 2
• Statistically significant reductions in back pain (p=0.01) and leg pain (p=0.002) compared to decompression alone 1
• 93% patient satisfaction rates at long-term follow-up 1
• Fusion rates of 89-95% with instrumented techniques versus 67-92% with posterolateral fusion alone 1

The presence of facet fluid on MRI correlates with dynamic instability and predicts anterolisthesis on weight-bearing flexion-extension radiographs that may not be evident on supine MRI. 6

When Decompression Alone is Appropriate

Decompression without fusion is the recommended treatment for: 2

• Stenosis with neurogenic claudication without documented instability or spondylolisthesis 2
• Isolated radiculopathy from foraminal stenosis without vertebral slippage 1, 2
• Cases where limited decompression (undercutting, laminotomy) can adequately decompress neural elements without extensive facet removal 5, 2

A major pitfall is performing fusion for isolated stenosis without instability, which increases operative time, blood loss, and surgical risk without proven benefit. 1, 2

Surgical Technique Selection

Instrumentation Recommendations

Pedicle screw fixation improves fusion success rates from 45% to 83% (p=0.0015) in patients with spondylolisthesis and should be considered standard. 1, 2

• Instrumentation is specifically recommended when preoperative spinal instability exists (spondylolisthesis, bilateral pars defects, dynamic instability) 1, 2
• Instrumentation is NOT recommended for stenosis without deformity or instability, as it increases complication rates without improving outcomes 2

Interbody Fusion Techniques

Transforaminal lumbar interbody fusion (TLIF) provides high fusion rates (92-95%) while allowing simultaneous decompression through a unilateral approach. 1

• TLIF is appropriate for spondylolisthesis with foraminal stenosis requiring fusion 1
• Anterior lumbar interbody fusion (ALIF) with posterior instrumentation provides superior outcomes for L5-S1 pathology, improving lumbar lordosis and reducing sagittal malalignment 1
• Interbody techniques demonstrate fusion rates of 89-95% compared to 67-92% with posterolateral fusion alone 1

Bone Graft Options

Local autograft harvested during laminectomy combined with allograft provides equivalent fusion outcomes to iliac crest bone graft while avoiding donor site morbidity (58-64% donor site pain at 6 months). 1

• Grade B evidence supports rhBMP-2 as a bone graft extender in instrumented posterolateral fusions, though postoperative radiculitis occurs in 14% of cases 1
• Grade C evidence supports β-tricalcium phosphate/local autograft as a substitute for iliac crest bone with comparable fusion rates 1

Risk Stratification and Complications

Factors Predicting Poor Outcomes with Decompression Alone

Preoperative spondylolisthesis is the main risk factor for 5-year clinical and radiographic failure, with up to 73% risk of progressive slippage after decompression alone. 5, 2

• Multilevel laminectomies increase the incidence of progressive spondylolisthesis 5
• Extensive (wide) decompression and facetectomy correlate with increased incidence of delayed deformity 5
• Only 9% of patients without preoperative instability develop delayed slippage after decompression, suggesting prophylactic fusion is not routinely indicated 5, 2

Complication Rates

Instrumented fusion procedures carry higher complication rates (31-40%) compared to decompression alone (6-12%) or non-instrumented fusion. 1

• Common complications include cage subsidence, new nerve root pain, and hardware issues that typically don't require immediate intervention 1
• Extensive decompression without fusion carries a 37.5% risk of late instability development 2
• Adjacent segment disease occurs in approximately 10% of patients within 2 years, even with dynamic stabilization systems 7

Special Considerations

Multilevel Disease

Each level must independently meet fusion criteria—the presence of instability at one level does not justify fusion at adjacent stable levels. 1

• Fusion should be limited to levels with documented instability or where extensive decompression will create iatrogenic instability 1, 2
• Blood loss and operative duration are significantly higher in multilevel fusion procedures 2
• Patients with less extensive surgery tend to have better outcomes than those with extensive decompression and fusion when instability is absent 5, 2

Traumatic Anterolisthesis

High-grade traumatic anterolisthesis from pedicle avulsion (rather than facet/pars disruption) is relatively stable due to intact posterior ligamentous complex and can be managed with decompression and pedicle screw fixation at affected levels. 8

Dynamic Stabilization

Dynamic transpedicular stabilization (Dynesys system) combined with decompression reduces back pain from 6.5 to 2.5 and leg pain from 5.4 to 0.6 at 2-year follow-up in single-level degenerative anterolisthesis, avoiding bone grafting requirements. 7

• However, it does not prevent adjacent segment disease (10% incidence at 2 years) 7
• Screw loosening occurs in approximately 7% of cases 7

Critical Documentation Requirements

Before approving fusion, verify documentation of: 1, 2

• Imaging demonstrating moderate-to-severe stenosis with neural compression at the level corresponding to clinical findings 1, 2
• Flexion-extension radiographs confirming instability (if spondylolisthesis is not evident on static films) 5, 6
• Completion of formal supervised physical therapy for at least 6 weeks, not just home exercises 1
• Failed trials of anti-inflammatory medications and neuroleptic agents if radiculopathy is present 1
• Physical examination findings correlating with imaging abnormalities 1, 2

The absence of any of these elements, particularly formal physical therapy completion or imaging-confirmed neural compression, constitutes grounds for denial of fusion. 1, 2