Is a spinal bone autograft (20936) and inserter for a biomechanical device (22853) medically necessary for a patient with cervical spinal stenosis and radiculopathy?

Medical Necessity Assessment for Spinal Bone Autograft (20936) and Biomechanical Device Insertion (22853)

Yes, both the spinal bone autograft (20936) and biomechanical device insertion (22853) are medically necessary for this patient undergoing C6-7 anterior cervical discectomy and fusion (ACDF) for symptomatic cervical stenosis with radiculopathy that has failed conservative management.

Clinical Justification for Surgical Intervention

This 53-year-old male meets clear criteria for surgical intervention:

• Documented anatomic pathology: Moderate to advanced central canal stenosis at C6-7 with left foraminal disc protrusion directly correlating with his left-sided radicular symptoms 1, 2
• Failed conservative management: He has exhausted appropriate non-operative treatments including chiropractic care, anti-inflammatories, activity modification, and physical therapy 2, 3
• Progressive neurologic symptoms: He demonstrates objective weakness in the triceps with episodes of near-dropping, combined with persistent numbness and tingling in a C7 distribution (left hand, fingers, forearm, triceps, shoulder) 2, 4
• Functional impairment: His symptoms significantly impact activities of daily living, meeting the threshold for surgical consideration 2, 5

Medical Necessity of Spinal Bone Autograft (20936)

Autograft bone harvested from the iliac crest is recommended as the gold standard for creating arthrodesis in 1- to 2-level ACDF procedures with Class II evidence supporting its use 6, 1.

Superior Fusion Rates

• Autograft demonstrates fusion rates of 97% for single-level procedures compared to 94% for allograft 6
• For multilevel procedures, autograft achieves 100% fusion rates compared to 89.5% for allograft 1
• Autograft provides osteogenic, osteoinductive, and osteoconductive properties that promote solid fusion 5, 3

Clinical Rationale for This Specific Case

• The patient has moderate to advanced stenosis with significant degenerative changes (disc osteophyte complex, uncovertebral spurring, facet hypertrophy) that increase the technical challenge of achieving solid fusion 1
• Achieving solid arthrodesis is critical for long-term outcomes in patients with moderate stenosis and radiculopathy who have failed conservative management 1
• The use of autograft eliminates concerns about disease transmission or immunologic rejection that may occur with allograft materials 5

Acceptable Alternatives

While autograft is the gold standard, the following alternatives are also recommended:

• Allograft bone from cadaveric iliac crest or fibula is recommended with Class II evidence, though it shows lower fusion rates in some studies 6
• Titanium cages and rectangular fusion devices with or without autologous graft are recommended with Class II evidence 6
• PEEK cages may be considered with Class III evidence, though they have less robust supporting data 6

Important Caveat: Donor Site Morbidity

• Autograft harvest from the iliac crest causes donor site complications in up to 22-34% of patients, with 3% reporting unacceptable pain 6, 2
• This morbidity must be weighed against the superior fusion rates, particularly in patients with significant degenerative changes 6, 1
• Independent assessment of donor site pain reveals higher rates than surgeon-reported rates, emphasizing the need for informed consent 6

Medical Necessity of Biomechanical Device Insertion (22853)

The insertion of a biomechanical device (interbody cage or spacer) is medically necessary as part of the ACDF procedure to maintain disc space height, provide immediate structural support, and facilitate fusion 6.

Evidence Supporting Device Use

• Titanium cages and rectangular fusion devices are recommended for creating arthrodesis after 1- or 2-level ACDF with Class II evidence 6
• These devices provide a physiologically dynamic support system that protects neural structures and decreases mechanical pain through mature bony fusion 5
• The device maintains interspace height while the autograft incorporates and achieves solid fusion 6

Device Options

The following biomechanical devices are supported by evidence:

• Titanium cages: Recommended with Class II evidence for 1- or 2-level ACDF 6
• PEEK cages: May be considered with or without hydroxyapatite, though hydroxyapatite alone may result in more settling and fragmentation (Class III evidence) 6
• Carbon fiber cages: Recommended with fusion rates >50% (Class III evidence) 6

What NOT to Use

• PMMA (polymethylmethacrylate): Not recommended as a spacer because fusion generally does not occur, despite short-term results similar to bone grafts (Class II evidence, strength of recommendation B) 6
• rhBMP-2: Not recommended for routine use due to complication rates of 23-27% (especially local edema) compared to 3% for standard approaches, prompting an FDA public health notification (Class II evidence) 6

Critical Considerations for This Patient

Risk Factors for Pseudarthrosis

• Smoking status: Must be assessed, as smoking negatively impacts fusion rates, particularly with allograft materials 1
• Multilevel disease: While this patient is undergoing single-level fusion at C6-7, he has multilevel stenosis (C3/4, C5/6, C6/7) that may require future intervention 6, 4
• Adjacent level degeneration: The presence of moderate stenosis at C5/6 and C3/4 increases the risk of future adjacent segment disease 6

Surgical Planning

• The planned C6-7 ACDF addresses the most severe level (moderate to advanced central canal stenosis with left foraminal disc protrusion) 1, 2
• The combination of autograft and a biomechanical device provides both immediate structural support and long-term biological fusion 6, 5
• Anterior cervical plating may enhance arthrodesis rates, particularly in multilevel procedures, though this patient is undergoing single-level fusion 6

Monitoring for Complications

• Pseudarthrosis: Occurs in approximately 3-6% of single-level ACDF procedures with autograft, but rates increase significantly in multilevel procedures (14% per level in 3-4 level fusions) 6, 4
• Graft collapse: More common with allograft in multilevel cases (3.0 mm vs 1.8 mm for autograft, p=0.005) 1
• Donor site pain: Requires independent assessment beyond routine surgeon follow-up, as patients report higher rates of persistent pain than surgeons document 6

Summary of Medical Necessity

Both procedures are medically necessary because:

1. The patient meets clear surgical indications: Symptomatic cervical stenosis with radiculopathy, objective neurologic deficits, and failed conservative management 2, 3
2. Autograft provides superior fusion rates: Particularly important given the patient's moderate to advanced stenosis with significant degenerative changes 6, 1
3. The biomechanical device is essential: It maintains disc space height and provides structural support while fusion occurs 6, 5
4. The combination optimizes outcomes: Using both autograft and a structural device maximizes the likelihood of solid fusion and symptom resolution 6, 1