Sp bone agrft struct add-on

CPT 20938 covers the additional work of placing structural bone graft material during spinal surgery to support fusion or repair. This is an add-on code billed in addition to the primary spinal procedure code.

Showing rates for

National Average

Base Medicare rate

$177.58

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

3.02

PE RVU (NF)

1.53

MP RVU

0.94

Total RVU

5.49

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

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Billing tips

Always verify the primary spinal fusion code includes structural graft at one level; 20938 is only for additional segments beyond the first
Impact: Prevents denial of add-on code when no appropriate primary procedure is documented; saves $177.58 per incorrectly billed unit
Document each vertebral segment receiving structural graft with specific anatomic levels (e.g., L4-L5, L5-S1) in operative report
Impact: Supports medical necessity for each unit billed; multi-level cases averaging 2-3 add-on codes yield $355-$532 in additional reimbursement
Bill one unit of 20938 for each additional vertebral segment beyond the first, not per interspace or per side
Impact: Correct unit reporting prevents downcoding; overbilling 3 units instead of 2 creates $177.58 overpayment subject to recoupment
Differentiate structural bone graft (20938) from morselized graft material; only structural grafts providing mechanical support qualify
Impact: Prevents upcoding allegations; structural grafts include cages, spacers with bone, or cortical/cancellous blocks, not demineralized bone matrix alone
Submit 20938 on the same claim as the primary fusion code with identical date of service; link to same diagnosis codes
Impact: Add-on codes submitted separately or with different dates trigger automatic denials requiring manual appeals and delaying payment 30-60 days
Review LCD and NCD policies for structural bone graft medical necessity criteria in your MAC jurisdiction before surgery
Impact: Pre-operative verification prevents denials for experimental or investigational designations; MAC-specific policies vary on synthetic vs. allograft coverage

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Frequently asked questions

What is the Medicare reimbursement rate for CPT code 20938 in 2025?

The 2025 Medicare national average reimbursement for CPT 20938 is $177.58 for both facility and non-facility settings. This rate is based on 5.49 total RVUs multiplied by the 2025 conversion factor of 32.3465.

Can CPT 20938 be billed alone or does it require a primary procedure code?

CPT 20938 is an add-on code and cannot be billed alone. It must be reported with a primary spinal fusion procedure code such as 22558, 22585, 22630, or 22633. The primary code includes structural graft at the first segment; 20938 covers each additional segment.

How many units of CPT 20938 can be billed for a three-level spinal fusion?

For a three-level fusion with structural bone graft at all levels, you would bill two units of 20938. The primary fusion code includes the first segment's structural graft, and 20938 is reported once for each of the two additional segments receiving structural graft.

What is the difference between CPT 20938 and morselized bone graft codes?

CPT 20938 is specifically for structural bone grafts that provide mechanical load-bearing support (cages, spacers, cortical blocks). Morselized grafts are small bone particles used for osteogenic potential and are typically included in the primary fusion code or reported with different codes like 20930-20931.

What RVU values are assigned to CPT code 20938 for 2025?

CPT 20938 has 3.02 work RVUs, 1.53 practice expense RVUs (both facility and non-facility), and 0.94 malpractice RVUs, totaling 5.49 RVUs. These values are from the CMS 2025 Medicare Physician Fee Schedule released December 23, 2024.

Does CPT 20938 require modifier 51 for multiple procedure reduction?

No, CPT 20938 is designated as modifier 51 exempt because it is an add-on code. Add-on codes are never subject to multiple procedure payment reductions, so modifier 51 should not be appended and may cause processing errors if used.

What documentation is required to support billing CPT 20938?

Documentation must include specific vertebral segment identification for each structural graft placement, graft type and source, description of structural support provided, and clear distinction between the primary level (included in base code) and each additional segment. The operative report must detail the technique and medical necessity for multi-level structural grafting.