Medical Necessity Determination for Spinal Bone Autograft (CPT 20936)
Spinal bone autograft (CPT 20936) is NOT medically necessary for this 3-level ACDF procedure, as the requested allograft (CPT 20930) combined with interbody devices provides equivalent fusion rates without the additional morbidity of autograft harvest. 1
Evidence-Based Rationale
Guideline Recommendations for Graft Selection
The Journal of Neurosurgery guidelines establish that autograft bone harvested from iliac crest, allograft bone from cadaveric sources, or titanium cages with or without autologous graft are all recommended options for creating arthrodesis after ACDF (Class II evidence, Strength C recommendation). 1 Critically, these guidelines do not prioritize autograft over allograft—they are presented as equivalent options.
Clinical Context Analysis
For this patient's 3-level ACDF (C4-5, C5-6, C6-7):
The patient meets all criteria for the primary fusion procedures based on severe central stenosis, moderate foraminal stenosis, cord flattening with myelomalacia, failed conservative management, and significant functional impairment 2
Allograft (CPT 20930) is already approved per CPB 0411, which states cadaveric allograft is medically necessary for spinal fusions 2
Interbody devices (CPT 22853) are already approved per CPB 0016 for patients meeting fusion criteria 2
Why Additional Autograft is NOT Necessary
The combination of allograft with interbody cages achieves fusion rates of 91-95% for multilevel cervical fusion, which is equivalent to autograft alone. 1, 3 Specifically:
- Titanium cages with allograft achieve 95% fusion rates at 5+ years follow-up 3
- Allograft combined with interbody devices provides structural support and maintains disc height critical for foraminal decompression 2
- For multilevel disease, instrumentation (already approved as CPT 22846) provides the stability needed, reducing pseudarthrosis risk from 4.8% to 0.7% 2
Autograft Harvest Morbidity Considerations
Adding iliac crest autograft harvest introduces donor site morbidity without improving fusion outcomes when allograft and cages are already utilized. 1 The guidelines specifically note that "graft harvest morbidity and patient preference should be considered when selecting the type of graft." 1
Clinical Decision Algorithm
Is the primary fusion procedure medically necessary? YES - Patient meets all criteria for 3-level ACDF 2
Is bone graft material needed for fusion? YES - Required for interbody arthrodesis 1
Is allograft already approved? YES - CPT 20930 is certified per CPB 0411 2
Are interbody devices already approved? YES - CPT 22853 is certified per CPB 0016 2
Would adding autograft improve fusion rates beyond allograft + cage + instrumentation? NO - Equivalent outcomes 1, 3
Does autograft add morbidity? YES - Donor site complications without added benefit 1
CONCLUSION: CPT 20936 is NOT medically necessary
Common Pitfalls to Avoid
Do not conflate "autograft is an option" with "autograft is necessary" - The guidelines present multiple equivalent options, not a hierarchy 1
Do not approve autograft simply because it was requested - Medical necessity requires demonstrating benefit over already-approved alternatives 1
Recognize that multilevel fusion with instrumentation already provides optimal stability - The approved plate fixation (CPT 22846) reduces pseudarthrosis risk more effectively than graft selection alone 2
Alternative local autograft sources exist if surgeon insists on autograft - Manubrium, clavicle, or local cervical vertebral bone can be harvested without separate incision or CPT 20936 billing 4, 5, 6
Coverage Determination
DENY CPT 20936 - The combination of approved allograft (20930), interbody devices (22853), and anterior cervical plating (22846) provides equivalent fusion outcomes without the additional morbidity and cost of iliac crest autograft harvest. 1, 3