What is a laminectomy with Coflex (interlaminar stabilization device) for spinal stenosis?

Laminectomy with Coflex for Lumbar Spinal Stenosis

Laminectomy with Coflex interlaminar stabilization is an FDA-approved, motion-preserving alternative to traditional decompression and fusion for treating moderate lumbar spinal stenosis with or without low-grade (Grade 1) degenerative spondylolisthesis, offering equivalent clinical outcomes with shorter operative times, less blood loss, and reduced adjacent-level degeneration compared to instrumented fusion. 1

What is the Coflex Device?

The Coflex is an interspinous interlaminar stabilization device implanted between the spinous processes after decompressive laminectomy 2. Unlike rigid pedicle screw fusion, it provides dynamic stability that unloads the facet joints, restores foraminal height, and maintains controlled motion at the operative level while preventing excessive extension 3, 1.

FDA-Approved Indications

The Coflex device is FDA-approved for patients with:

• Moderate lumbar spinal stenosis at 1-2 levels 1
• Neurogenic claudication unresponsive to conservative management 2
• Grade 1 degenerative spondylolisthesis or less 4, 1
• No more than Grade 1 anterolisthesis at the operative level 5

Clinical Outcomes: Coflex vs. Fusion

Equivalent Efficacy at 2 Years

A prospective, randomized, multicenter FDA Investigational Device Exemption trial of 322 patients demonstrated noninferiority of Coflex compared to posterolateral fusion 1:

• Overall FDA success rate: 66.2% for Coflex vs. 57.7% for fusion (p = 0.999) 1
• Oswestry Disability Index: Both groups showed significant improvement, with a trend toward greater improvement in Coflex (p = 0.075) 1
• Visual analog scale scores: Both groups demonstrated equivalent improvement in back and leg pain 1

In the spondylolisthesis subgroup (99 Coflex, 51 fusion patients), FDA overall success was achieved in 62.8% of Coflex subjects and 62.5% of fusion controls (p = 1.000) 4.

Perioperative Advantages

Coflex patients experienced significantly superior perioperative outcomes: 1

• Operative time: Significantly shorter (p < 0.0001)
• Blood loss: Significantly less (p < 0.0001)
• Length of stay: Significantly shorter (p < 0.0001)

Quality of Life Outcomes

Coflex demonstrated superior patient-reported outcomes in multiple domains 1:

• SF-12 physical health: Greater improvement (p = 0.050)
• Zurich Claudication Questionnaire: Significant superiority in symptom severity (p = 0.023), physical function (p = 0.008), and patient satisfaction (p = 0.006)

Adjacent Level Effects: Critical Difference

Fusion creates biomechanical stress at adjacent levels, while Coflex preserves normal motion patterns 4, 1:

• Fusion patients: Experienced significantly increased angulation at superior adjacent levels (p = 0.002) and increased translation at both superior and inferior levels 4
• Coflex patients: Maintained normal operative and adjacent level motion with no significant radiographic changes from baseline 4, 1

This preservation of motion mechanics may reduce the risk of adjacent segment disease, a well-documented long-term complication of rigid fusion 4.

Reoperation Rates: Important Caveat

The primary disadvantage of Coflex is a higher reoperation rate 4, 1:

• Coflex reoperation rate: 10.7-14.1% 4, 1
• Fusion reoperation rate: 5.9-7.5% 4, 1
• This difference was not statistically significant (p = 0.18-0.426) but represents a clinically relevant trend 4, 1

Comparison to Laminectomy Alone

A prospective controlled study of 60 patients compared decompression alone versus decompression with Coflex 3:

• Both groups showed significant improvement in ODI, Roland-Morris scores, VAS, and walking distance (p < 0.001) 3
• No statistically significant differences between groups at 1-year follow-up in any clinical parameter or patient satisfaction 3
• This study suggests Coflex may not provide additional benefit over decompression alone in unselected patients 3

Patient Selection Algorithm

Coflex is most appropriate for patients meeting ALL of the following criteria:

1. Moderate lumbar stenosis at 1-2 levels causing neurogenic claudication 2, 1
2. Failed conservative management (minimum 6 weeks of physical therapy per standard guidelines) 6
3. Grade 1 or less spondylolisthesis (Coflex is contraindicated in higher-grade slips) 4, 5
4. No significant instability on flexion-extension radiographs 7
5. Preserved lumbar lordosis (kyphotic deformity requires fusion) 7
6. Patient preference for motion preservation over potentially lower reoperation rates 4, 1

Common Pitfalls to Avoid

Do not use Coflex in patients with:

• Grade 2 or higher spondylolisthesis (fusion is indicated per guidelines) 7
• Significant preoperative instability on dynamic imaging (>3mm translation or >10° angulation) 7
• Kyphotic deformity requiring realignment 7
• Multilevel stenosis >2 levels (outside FDA approval) 1
• Severe stenosis requiring wide decompression with extensive facetectomy (creates iatrogenic instability requiring fusion) 7

Key consideration: While Coflex preserves motion and reduces adjacent-level stress, the higher reoperation rate means patients must accept this trade-off for the benefits of motion preservation and less invasive surgery 4, 1.