Partial reconstruction of the mandible or maxilla using a subperiosteal implant — a custom metal framework placed on top of the jawbone beneath the periosteum to restore structural integrity and function.

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

• Specify the jaw segment reconstructed — mandible or maxilla — and confirm 'partial' extent (less than full arch).
• Document the implant type as subperiosteal, distinguishing it from endosteal (21248/21249) or extraoral transosteal (21244) approaches.
• State the clinical indication by name: trauma, congenital defect, severe resorption, oncologic resection, or other documented etiology.
• Include operative note detailing subperiosteal dissection, implant fit, and fixation method — audit teams flag notes that omit approach specifics.
• If modifier 22 is appended, the note must quantify increased complexity: operative time, blood loss, degree of bone loss, or unusual anatomical challenges.
• If abutment posts were not placed, document this explicitly to support modifier 52 when applicable.
• Record imaging used for preoperative planning (CT, CBCT) and confirm it supports the partial versus complete extent distinction.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Common denial reasons

The recurring reasons claims for CPT 21245 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

• Dental benefit carve-out: payer routes the claim to the dental plan rather than medical, even when the indication is trauma or oncologic.
• Missing or insufficient medical necessity documentation — payers require explicit diagnosis linking skeletal defect to functional impairment.
• Incorrect code selection: billing 21245 when the full arch is involved (should be 21246) triggers downcoding or denial on audit.
• NCCI bundling conflict when companion codes (e.g., transfusion or graft harvest codes) are billed without a modifier that permits separate reporting.
• Global period violation: postoperative E/M visits billed without modifier 24 during the 90-day window are denied as included in the surgical package.