Is spinal bone autograft (Spinal Bone Autograft) medically necessary for a patient with chronic lumbar pain, lumbar stenosis, and grade 1 anterolisthesis undergoing bilateral lumbar laminotomy and foraminotomy with facet joint augmentation?

Medical Necessity Assessment for Spinal Bone Autograft (CPT 20936) in Bilateral Laminotomy/Foraminotomy Without Fusion

Spinal bone autograft (CPT 20936) is NOT medically necessary for this patient undergoing bilateral lumbar laminotomy and foraminotomy without fusion, as the planned procedure is decompression alone without any fusion component, and autograft is only indicated when arthrodesis is being performed. 1

Fundamental Distinction: Decompression vs. Fusion

The critical issue here is that the surgeon explicitly plans decompression with facet joint augmentation without instrumentation and no hardware - this is not a fusion procedure. 1

• Bone autograft is only medically necessary when performing spinal fusion/arthrodesis, where bone graft material is required to achieve solid bony union between vertebral segments. 1
• The planned bilateral laminotomy and foraminotomy is a decompressive procedure that removes bone and ligament to relieve neural compression, not a fusion procedure. 1, 2
• CPT code 20936 specifically describes autograft for spine surgery "through separate skin or fascial incision" and is intended for fusion procedures requiring graft material. 1

Evidence Supporting Decompression Alone in This Clinical Scenario

This patient's presentation actually supports decompression without fusion:

• Grade 1 anterolisthesis without significant instability does not require fusion. The Journal of Neurosurgery guidelines explicitly state that "in situ posterolateral lumbar fusion is not recommended as a treatment option in patients with lumbar stenosis in whom there is no evidence of preexisting spinal instability." 1
• The surgeon's own assessment notes "no significant instability" and states that "decompression with facet augmentation is better than long segmental fusion with hardware" for this patient. 1
• Decompression alone achieves 60-75% good outcomes in patients with lumbar stenosis without significant instability. 1, 3, 2

When Fusion (and Therefore Autograft) Would Be Indicated

Fusion with bone graft would only be medically necessary if:

• Documented spinal instability exists (not present in this case per surgeon's note). 1, 4
• Extensive facetectomy is required that would create iatrogenic instability (not planned here - only foraminotomy). 1, 3
• Grade II or higher spondylolisthesis with dynamic instability on flexion-extension films (this patient has grade 1 without documented instability). 5, 6, 7

Facet Joint Augmentation Does Not Equal Fusion

The term "facet joint augmentation" in the surgical plan likely refers to:

• Facet preservation techniques or limited facet trimming during decompression, not fusion. 3, 2
• Possibly injection of bone cement or other materials to stabilize the facet without formal arthrodesis. 3
• This does not constitute spinal fusion requiring bone graft material. 1

Critical Pitfall to Avoid

Do not confuse decompression procedures with fusion procedures. The presence of anterolisthesis alone does not mandate fusion if no instability exists, and performing unnecessary fusion increases complications (31-40% vs 6-12% for decompression alone) without improving outcomes in stable patients. 1, 6

What Would Be Appropriate for This Patient

For the planned bilateral L4-5 and L5-S1 laminotomy and foraminotomy:

• No bone graft of any type is required - decompression removes bone rather than adding it. 1, 2
• Local bone removed during decompression can be saved and used if the surgeon later decides intraoperatively that limited fusion is necessary, but this would require different CPT coding. 7, 3
• If fusion becomes necessary intraoperatively due to unexpected instability, local autograft harvested from the laminotomy/foraminotomy provides sufficient material for limited posterolateral fusion. 1, 7, 8

Conclusion on Medical Necessity

CPT 20936 (spinal bone autograft) should be denied as not medically necessary because the planned procedure is decompression without fusion, and bone graft material is only indicated when performing arthrodesis to achieve bony union between vertebral segments. 1