21025

🦴 CPT Code 21025 — Excision of Bone (eg, Osteomyelitis or Bone Abscess); Mandible

Quick Reference

Global Period: 090 days | wRVU: 10.42 | Assistant Payable: ✅ Yes | Co-Surgeon: ❌ No | Category: Musculoskeletal – Head | Primary Indication: Osteomyelitis / Bone Abscess / Necrosis of Mandible

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📋 Official CPT Description

21025 — Excision of bone (eg, osteomyelitis or bone abscess)

This code describes the surgical excision of mandibular bone in the setting of osteomyelitis, bone abscess, or other destructive infectious/inflammatory conditions requiring removal of necrotic, infected, or nonviable bone tissue. The procedure encompasses a spectrum of surgical interventions ranging from limited sequestrectomy (removal of isolated dead bone fragments — sequestra) to more extensive partial mandibulectomy for advanced osteomyelitic disease, always in the context of infection or abscess rather than primary neoplasm.

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🧠 Detailed Clinical Description

What Is 21025?

CPT 21025 captures mandibular bone excision performed specifically in the context of osteomyelitis (bone infection) or bone abscess — two closely related conditions involving bacterial, fungal, or ischemia-driven destruction of mandibular osseous tissue. The defining characteristic separating 21025 from the mandibular tumor excision codes (21044, 21045) is the etiology: 21025 is driven by infection, inflammation, or avascular necrosis, not by primary or secondary malignancy.

The procedure may be performed at varying levels of surgical aggressiveness depending on disease extent:

Surgical Level	Description
Sequestrectomy	Removal of isolated necrotic bone fragments (sequestra) with preservation of surrounding viable bone; minimal osseous loss
Saucerization / Decortication	Removal of outer cortical plate and saucerizing the medullary cavity to promote vascularization and healing; open wound management
Partial Mandibulectomy	Excision of a mandibular segment — marginal (inferior border preserved) or segmental (continuity interrupted) — for advanced osteomyelitis not amenable to limited debridement
Sequestrectomy with Primary Closure	Sequestrum removed, periosteum mobilized and primarily closed over defect

Primary Clinical Entities Coded Under 21025

1. Osteomyelitis of the Mandible

Osteomyelitis of the jaw is an infectious process involving the medullary bone, cortex, and periosteum of the mandible. The mandible’s dense cortical architecture and relatively limited collateral circulation (particularly following prior radiation or vascular compromise) make it susceptible to protracted infection.

Classification:

Type	Description	Common Pathogens
Acute osteomyelitis	Rapid onset, <4 weeks; suppurative with medullary abscess	S. aureus, mixed oral flora
Chronic osteomyelitis	Persistent >4 weeks; sequestrum formation, involucrum	Actinomyces, mixed oral anaerobes
Chronic sclerosing osteomyelitis	Dense reactive bone, pain, no frank suppuration; juvenile or diffuse adult type	Often no identifiable pathogen
Osteoradionecrosis (ORN)	Radiation-induced ischemic necrosis of mandibular bone, prone to secondary infection	Mixed flora, opportunistic
MRONJ	Medication-related osteonecrosis of the jaw; bisphosphonates, denosumab, anti-angiogenics	Oral flora; Actinomyces common

2. Bone Abscess of the Mandible

A mandibular bone abscess is a localized purulent collection within the medullary cavity or beneath the periosteum of the mandible, typically arising from:

• Periapical abscess with cortical penetration
• Periodontal disease with osseous involvement
• Hematogenous seeding (less common in the jaw)
• Extension from adjacent soft tissue infection

Surgical drainage and debridement — including removal of the abscess cavity walls and necrotic bone — constitutes the 21025 procedure.

3. Osteoradionecrosis (ORN) of the Mandible

ORN results from radiation-induced endarteritis obliterans — progressive obliteration of small blood vessels within the mandibular bone — following therapeutic radiation to the head and neck (typically doses >60 Gy). The hypoxic, hypovascular, and hypocellular tissue cannot support normal bone turnover or resist infection, leading to progressive necrosis.

Marx Staging System for ORN:

Stage	Description	Surgical Relevance
Stage I	Exposed bone, responsive to hyperbaric oxygen (HBO)	Limited sequestrectomy possible
Stage II	Exposed bone, failed Stage I treatment	Transoral debridement and sequestrectomy (21025)
Stage III	Full-thickness necrosis, pathologic fracture, or oroantral/orocutaneous fistula	Segmental resection with reconstruction (21045 if graft; free flap 15756)

ORN vs. Malignant Recurrence

ORN of the mandible can mimic tumor recurrence on imaging and clinically. Biopsy confirmation is essential before surgical planning. If biopsy confirms necrotic/inflammatory bone without malignancy → 21025. If biopsy confirms recurrent/residual malignancy → 21044 or 21045.

4. MRONJ — Medication-Related Osteonecrosis of the Jaw

MRONJ is an increasingly common indication for 21025, driven by the widespread use of:

• Bisphosphonates (zoledronic acid, alendronate, risedronate) — for osteoporosis, bone metastases, multiple myeloma
• Denosumab (RANKL inhibitor) — for bone metastases and osteoporosis
• Anti-angiogenic agents (bevacizumab, sunitinib) — oncologic indications

AAOMS Staging of MRONJ:

Stage	Criteria	Management
At-Risk	On antiresorptive/antiangiogenic agents; no necrotic bone	Patient education, preventive dental care
Stage 0	No clinical evidence of necrotic bone; nonspecific symptoms/imaging changes	Conservative management
Stage 1	Exposed/necrotic bone, asymptomatic, no infection	Antimicrobial rinses; consider debridement
Stage 2	Exposed/necrotic bone with infection (pain, erythema, purulence)	Antibiotics + surgical debridement (21025)
Stage 3	Exposed/necrotic bone with pain, infection plus one of: pathologic fracture, extra-oral fistula, osteolysis extending to inferior border	Resection + reconstruction (21045 if graft required)

MRONJ Stage 2–3 and Code Selection

• Stage 2 MRONJ → Surgical debridement and necrotic bone removal → 21025
• Stage 3 MRONJ with segmental resection requiring bone graft → 21045 (malignant if driven by metastatic disease context) or 21025 with modifier 22 if non-malignant but highly complex
• Assess whether the underlying indication for antiresorptive therapy was malignant (bone mets, myeloma) vs. benign (osteoporosis) — this impacts diagnosis coding and HCC capture

Surgical Steps Included in 21025

1. Preoperative imaging review — Panoramic radiograph (OPG), CT scan (best for cortical detail), MRI (soft tissue extension), nuclear bone scan (technetium-99m for activity mapping); not separately billable within global
2. Patient positioning and airway management — Nasal or oral intubation; tracheotomy (31600) if required, billed separately
3. Incision and exposure — Intraoral (vestibular/crestal) and/or extraoral (submandibular Risdon approach) access depending on location and extent of disease
4. Periosteal elevation — Mucoperiosteal flap raised to expose involved bone
5. Identification and removal of sequestra — Necrotic bone fragments identified visually and tactilely (dry, chalky, avascular appearance); sequestra elevated and removed
6. Debridement of osteomyelitic cavity — Curettes and rongeurs used to remove infected medullary bone; burs used for saucerization of cavity walls
7. Wound irrigation — Copious saline or antiseptic irrigation of cavity (e.g., povidone-iodine, chlorhexidine)
8. Assessment of viable bone margins — Bleeding bone (paprika sign) indicates viable margins; carbonized or sclerotic non-bleeding bone requires further debridement
9. Wound closure vs. open packing — Primary closure if viable margins achieved; open pack or secondary intent healing for extensively infected cases
10. Culture and pathology specimens — Bone and soft tissue cultures, histopathologic evaluation to exclude malignancy and guide antimicrobial therapy
11. Postoperative management within global period — Wound checks, drain management, antimicrobial therapy coordination (not separately billable)

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💰 Reimbursement & RVU Profile

Component	Value
Work RVU (wRVU)	10.42 CMS MPFS 2025
Global Period	090 days
Assistant Surgeon Payable	✅ Yes
Co-Surgeon Payable	❌ No
Team Surgery	❌ No
Facility Only	Yes (hospital/ASC for most cases)
Multiple Procedure Indicator	2 (standard reduction applies)
Bilateral Surgery Indicator	0 (not applicable)

wRVU Context Within the Mandible Code Family

Code	wRVU	Procedure
21025	10.42	Mandible excision — osteomyelitis/abscess
21026	~8.74	Other facial bone excision — osteomyelitis
21040	~3.97	Benign mandible tumor excision, no graft
21044	~14.00	Malignant mandible tumor, no graft
21045	~22.93	Malignant mandible tumor + bone graft

21025 sits in a moderate-complexity tier, reflecting the operative demands of infected bone debridement — which can range from brief outpatient sequestrectomy to lengthy staged inpatient resection depending on disease extent and patient condition.

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✅ Included Services (Bundled into 21025)

The following are not separately reportable when performed as integral components of 21025:

• Intraoral and/or extraoral incision and exposure of mandibular bone
• Elevation of mucoperiosteal flap(s) at the operative site
• Sequestrectomy — removal of necrotic bone fragments
• Saucerization and decortication of the osteomyelitic cavity
• Intraoperative wound irrigation (saline, antiseptic)
• Intraoperative culture and tissue sampling (for pathology)
• Simple or intermediate closure of mucoperiosteal flap(s)
• Placement of surgical drains at the operative site
• Routine postoperative wound care within the 90-day global period
• Routine dressing changes, suture/staple removal within global
• Minor debridement at the same operative site within the same session

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❌ Excludes / Separately Reportable Services

The following may be billed separately when clearly documented as distinct services:

Separate Service	Code
Planned tracheotomy for airway management	31600
Bone graft reconstruction (when performed as part of same-session resection and defect filling)	20900, 20902
Hyperbaric oxygen therapy sessions (pre/postoperative adjunct)	99183
Neck dissection (if performed for regional lymphadenopathy/oncologic staging)	38720, 38724
Skin graft for soft tissue wound coverage at mandibular site	15100–15115
Free flap reconstruction for large segmental mandibular defect	15756, 15757, 15758
TMJ arthroscopy or reconstruction if TMJ involved separately	29800, 21240
Incision and drainage (I&D) of adjacent soft tissue abscess — distinct from bone procedure	41800, 41805
Return to OR for wound dehiscence or re-debridement (related, within global)	21025 with modifier 78
Removal of hardware (plates/screws) placed at prior surgery if separately documented	20670, 20680
Extraction of involved teeth at operative site (when separately and distinctly documented)	Dental codes (D7110–D7240) or 41820
Incision of periosteum or sinus tract (soft tissue only)	41820, 40800
Secondary debridement of unrelated wound at separate site	97597, 97598

Bone Graft With 21025 — A Nuanced Scenario

Unlike 21045 where the bone graft harvest is explicitly included in the CPT descriptor, 21025 does not contain language bundling bone graft harvest. Therefore, when a bone graft is performed as part of a same-session reconstruction following osteomyelitis resection (e.g., iliac crest graft to fill a sequestrectomy cavity), the graft harvest (20900, 20902) may be separately reportable. Verify current NCCI edits and payer policy. Document each procedure — resection and graft harvest — distinctly in the operative report. Some payers bundle; others allow separate billing with modifier 59 and clear documentation.

Soft Tissue vs. Bone Debridement — Code Selection

97597 and 97598 describe wound debridement codes typically applied to soft tissue wounds (skin, subcutaneous tissue, muscle). When the debridement involves bone (mandibular cortex, medullary cavity) — even in a wound-care setting — 21025 is the more specific and appropriate code. However, for Stage 1 MRONJ managed with conservative topical/local debridement in an office/clinic setting without surgical anesthesia, wound debridement codes may be applicable. The level of surgical intervention (OR vs. office, anesthesia type, bone vs. soft tissue predominance) drives the distinction.

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🔬 Comparison: 21025 vs. 21026

Distinguishing 21025 from 21026

Both codes describe excision of bone for osteomyelitis or bone abscess in the head region, but differ by anatomical site:

Feature	21025	21026
Anatomical Site	Mandible specifically	Other facial bones (maxilla, zygoma, orbit, frontal, nasal)
Example	Mandibular osteomyelitis sequestrectomy	Maxillary or frontal bone osteomyelitis excision
wRVU	10.42	~8.74
Global Period	090	090
Bone Graft Inclusion	Not explicitly bundled	Not explicitly bundled

Never assign 21026 for mandibular osteomyelitis — 21025 is the mandible-specific code.

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🏷️ Applicable Modifiers

Modifier	Description	When to Use
-51	Multiple procedures	When 21025 is performed alongside another procedure (e.g., I&D of soft tissue abscess, tooth extraction, tracheotomy) in the same operative session
-59	Distinct procedural service	To unbundle a separately identifiable service at a distinct anatomical location; e.g., bone graft harvest at donor site performed in addition to mandibular excision
-22	Increased procedural complexity	Extensive disease, prior radiation (ORN), immunocompromised patient, multi-segment involvement, dramatically prolonged OR time; must be documented specifically in operative note with cover letter
-52	Reduced services	Planned procedure terminated early (e.g., patient became hemodynamically unstable); partial completion of intended procedure
-58	Staged or related procedure by same surgeon	When 21025 is planned stage two of a staged procedure within global period
-78	Return to OR for related procedure during global period	Re-debridement for wound breakdown, persistent infection, recurrent sequestrum formation, or hardware complication within 90-day global
-79	Unrelated procedure during global period	Unrelated surgery performed within 90 days of original 21025
-80	Assistant surgeon	Second surgeon assisting; applicable for complex cases requiring two-surgeon approach
-LT / -RT	Left / Right laterality	When disease is lateralized (e.g., right body osteomyelitis vs. left ramus involvement); document per payer requirements

Modifier -22 in ORN / MRONJ Cases

Prior radiation to the jaw field is one of the strongest justifications for modifier -22 on 21025. The combination of endarteritis, avascular tissue planes, risk of pathologic fracture, and need for extended debridement significantly increases operative complexity. The operative note must explicitly describe — not merely mention radiation history — the specific technical challenges encountered. Include OR time documentation and a narrative cover letter with the claim. Expect payer review.

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🩺 ICD-10-CM Diagnoses Commonly Paired with 21025

Osteomyelitis of the Mandible / Jaw

ICD-10-CM	Description	HCC?
M27.2	Inflammatory conditions of jaws (includes suppurative osteomyelitis of jaws)	❌
M86.08	Acute hematogenous osteomyelitis, other bones	❌
M86.18	Other acute osteomyelitis, other bones (mandible specific)	❌
M86.28	Subacute osteomyelitis, other bones	❌
M86.38	Chronic multifocal osteomyelitis, other bones	❌
M86.48	Chronic osteomyelitis with draining sinus, other bones	❌
M86.58	Other chronic hematogenous osteomyelitis, other bones	❌
M86.68	Other chronic osteomyelitis, other bones	❌
M86.9	Osteomyelitis, unspecified	✅ HCC 39

ICD-10-CM Coding Precision for Mandibular Osteomyelitis

ICD-10-CM does not have a site-specific osteomyelitis code for the mandible within the M86 category. The mandible, as a facial bone, falls under the “other bones” subcategory (eighth character 8) or the jaw-specific category M27.2. Use M27.2 when the documentation specifically identifies inflammatory/suppurative conditions of the jaws — it is the most anatomically specific code. Use M86.x8 subcategories when the clinical documentation specifies the type and acuity of osteomyelitis (acute, subacute, chronic) with the understanding that the mandible maps to “other bones.”

M86.9 (Osteomyelitis, unspecified) is an HCC 39 — one of the few osteomyelitis-related codes that carries HCC weight. Assign when documentation does not allow greater specificity and osteomyelitis is the confirmed diagnosis.

Bone Abscess of the Jaw / Mandible

ICD-10-CM	Description	HCC?
M27.2	Inflammatory conditions of jaws (periapical abscess with bone involvement)	❌
K04.7	Periapical abscess without sinus	❌
K04.6	Periapical abscess with sinus	❌
K05.20	Aggressive periodontitis, unspecified	❌
K05.30	Chronic periodontitis, unspecified	❌
K10.2	Inflammatory conditions of jaws (osteomyelitis/periostitis of jaw)	❌
K12.2	Cellulitis and abscess of mouth	❌

Periapical Abscess with Bone Involvement → 21025

When a periapical abscess extends beyond the alveolar process to involve the cortical/medullary bone of the mandible requiring surgical bone debridement (not just I&D of soft tissue), 21025 is appropriate. Code the periapical abscess (e.g., K04.6 or K04.7) as the principal/primary diagnosis driving the procedure.

Osteoradionecrosis (ORN) of the Mandible

ICD-10-CM	Description	HCC?
M27.49	Other inflammatory conditions of jaw (maps radiation-induced ORN when no more specific code applies)	❌
M87.08	Idiopathic aseptic necrosis of bone, other (used for ORN in some facilities)	❌
M87.38	Other secondary osteonecrosis, other bones (radiation-induced osteonecrosis — secondary)	❌
K10.2	Inflammatory conditions of jaws	❌
T66.XXXA	Radiation sickness, unspecified; initial encounter (as additional etiology code for ORN)	❌
Y84.2	Radiological procedure and radiotherapy as cause of abnormal reaction or complication (external cause — ORN)	❌
Z85.819	Personal history of malignant neoplasm (if prior H&N cancer drove radiation)	❌

ORN Coding — No Single Perfect ICD-10-CM Code

ICD-10-CM does not have a dedicated code for osteoradionecrosis of the mandible. This is a known gap in the classification system. Best practice options in order of specificity:

1. M87.38 — Other secondary osteonecrosis, other bones (most pathophysiologically accurate — radiation-induced vascular damage → avascular necrosis of bone)
2. M27.49 — Other inflammatory conditions of jaw (commonly used by oral surgeons/oral med specialists for ORN)
3. K10.2 — Inflammatory conditions of jaws (less specific; acceptable when documentation is limited)

Pair the osteonecrosis code with T66.XXXA (radiation sickness/injury) or Y84.2 as an external cause code to capture the radiation etiology. Document “osteoradionecrosis” explicitly in the health record for coding support.

MRONJ — Medication-Related Osteonecrosis of the Jaw

ICD-10-CM	Description	HCC?
M87.18	Osteonecrosis due to drugs, other bones (mandible maps here — MRONJ)	❌
M87.08	Idiopathic aseptic necrosis, other bones	❌
T79.8XXA	Other early complications of trauma, initial (rarely applicable)	❌

MRONJ — External Cause Coding

When coding MRONJ (M87.18), always assign an additional external cause code to identify the causative drug:

Drug Class	External Cause Code
Zoledronic acid / IV bisphosphonates	T50.994A — Poisoning/adverse effect: other drugs affecting metabolism, initial
Oral bisphosphonates (alendronate, risedronate)	T50.994A
Denosumab (Prolia, Xgeva)	T50.994A — Adverse effect of antineoplastic/immunosuppressive drug
Bevacizumab / anti-VEGF agents	T45.1X5A — Adverse effect of antineoplastic and immunosuppressive drugs

Sequencing per ICD-10-CM adverse effect guidelines: Code the manifestation (M87.18) first, followed by the adverse effect code (T-code with 5th or 6th character “5” for adverse effect of correctly administered drug).

Underlying Conditions Driving MRONJ / Mandibular Osteomyelitis

ICD-10-CM	Description	HCC?
C90.00	Multiple myeloma, not having achieved remission	✅ HCC 10
C79.51	Secondary malignant neoplasm of bone	✅ HCC 11
C79.52	Secondary malignant neoplasm of bone marrow	✅ HCC 11
C50.919	Malignant neoplasm of unspecified site of unspecified female breast	✅ HCC 12
C61	Malignant neoplasm of prostate	✅ HCC 11
M81.0	Age-related osteoporosis without current pathological fracture	❌
M80.08XA	Age-related osteoporosis with current pathological fracture, other site, initial	❌
E11.9	Type 2 diabetes mellitus without complications	✅ HCC 19
D57.1	Sickle-cell disease without crisis	✅ HCC 46
B20	Human immunodeficiency virus disease	✅ HCC 1
D84.9	Immunodeficiency, unspecified	✅ HCC 47

HCC-Rich Comorbidity Capture for MRONJ Cases

Patients presenting for 21025 for MRONJ frequently carry high HCC burdens — multiple myeloma (C90.00, HCC 10), bone metastases (C79.51, HCC 11), diabetes (E11.9, HCC 19), or immunosuppression. In Medicare Advantage and value-based care environments, capturing all HCC-carrying diagnoses at every encounter — not just the one driving the procedure — is essential for accurate risk adjustment. Review the H&P, oncology notes, and medication reconciliation list before finalizing the coding.

Complications & Comorbidities Affecting DRG

ICD-10-CM	Description	HCC?
A41.9	Sepsis, unspecified organism	✅ HCC 2
A41.01	Sepsis due to Methicillin susceptible Staph aureus	✅ HCC 2
A41.02	Sepsis due to Methicillin resistant Staph aureus (MRSA)	✅ HCC 2
J96.00	Acute respiratory failure, unspecified whether with hypoxia or hypercapnia	✅ HCC 84
D62	Acute posthemorrhagic anemia	❌
E43	Unspecified severe protein-calorie malnutrition	✅ HCC 21
E44.0	Moderate protein-calorie malnutrition	✅ HCC 21
T84.50XA	Infection and inflammatory reaction due to unspecified internal joint prosthesis, initial	❌
K12.2	Cellulitis and abscess of mouth	❌
L03.211	Cellulitis of face	❌
K13.0	Diseases of lips (fistula of lip)	❌
K11.3	Abscess of salivary gland	❌

Sepsis from Mandibular Osteomyelitis — MCC Capture

Suppurative osteomyelitis of the mandible — particularly in immunocompromised, diabetic, or MRONJ patients — can progress to sepsis. When the provider documents sepsis (using Sepsis-2 or Sepsis-3 criteria) in the setting of 21025, code A41.9 or organism-specific sepsis as the principal diagnosis (per urosepsis/sepsis sequencing guidelines), with mandibular osteomyelitis as an additional diagnosis. Sepsis is an MCC that dramatically elevates DRG weight. Query the physician if clinical indicators are present (tachycardia, leukocytosis, fever, hypotension, elevated lactate, ICU admission) but sepsis is not explicitly documented.

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🏨 MS-DRG Mapping

Inpatient Context

In the inpatient acute care hospital setting, procedures are coded using ICD-10-PCS — CPT codes are not used. The ICD-10-PCS root operation for 21025-equivalent work is Excision (B) of mandibular bone (body system N – Head and Facial Bones). The principal diagnosis and CC/MCC burden determine the final MS-DRG assignment.

Head & Neck — Infectious / Osteomyelitis Context

MS-DRG	Description	Approx. Relative Weight
154	Other Ear, Nose, Mouth & Throat OR Procedures w/ MCC	~3.1–3.6
155	Other Ear, Nose, Mouth & Throat OR Procedures w/ CC	~2.0–2.4
156	Other Ear, Nose, Mouth & Throat OR Procedures w/o CC/MCC	~1.4–1.7

Musculoskeletal — Osteomyelitis Surgical Cases

MS-DRG	Description	Approx. Relative Weight
539	Osteomyelitis w/ MCC	~2.8–3.4
540	Osteomyelitis w/ CC	~1.7–2.1
541	Osteomyelitis w/o CC/MCC	~1.1–1.5

Major Head & Neck Procedures (Complex ORN / MRONJ with Reconstruction)

MS-DRG	Description	Approx. Relative Weight
168	Major Head & Neck Procedures w/ MCC	~3.8–4.2
169	Major Head & Neck Procedures w/ CC	~2.5–2.9
170	Major Head & Neck Procedures w/o CC/MCC	~1.8–2.1

Oral / Dental Procedures (Less Complex Cases)

MS-DRG	Description	Approx. Relative Weight
185	Dental & Oral Diseases w/ MCC	~1.8–2.1
186	Dental & Oral Diseases w/ CC	~1.1–1.4
187	Dental & Oral Diseases w/o CC/MCC	~0.8–1.0

DRG Optimization — High-Yield Query Targets for 21025 Cases

• Sepsis — Osteomyelitis with systemic infection signs → query for A41.9 (MCC; escalates DRG dramatically)
• Malnutrition — ORN and MRONJ patients frequently have dysphagia and poor oral intake → query for E43 (MCC) or E44.0 (CC) based on dietitian notes and lab values
• Acute blood loss anemia — Surgical debridement with significant hemorrhage + transfusion given → D62 (CC)
• MRSA infection — Culture-positive MRSA osteomyelitis → A41.02 (MCC for sepsis) or B95.62 (MRSA as cause of disease; CC/MCC per CMS grouper)
• Respiratory failure — Post-tracheotomy or airway edema in ORN patient → J96.00 (MCC)
• Underlying malignancy — Patients on bisphosphonates for bone mets/myeloma → C90.00 (HCC 10; MCC), C79.51 (HCC 11; MCC)

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🌳 CPT Code Tree — Facial Bone Excision / Mandible Pathology Family

Facial Bone Excision — Osteomyelitis / Abscess
├── 21025 ← EXCISION OF BONE, MANDIBLE — Osteomyelitis/Abscess (THIS CODE)
│     └── Mandible-specific; includes sequestrectomy, debridement, saucerization
│
└── 21026 — Excision of bone(s) of face — Osteomyelitis/Abscess
      └── Other facial bones (maxilla, zygoma, frontal, nasal, orbital)

Mandible Tumor Excision (Neoplastic — NOT 21025):
├── 21040 — Benign tumor/cyst, no graft, no extraction
├── 21041 — Benign tumor/cyst, tooth extraction required
├── 21044 — Malignant tumor, no bone graft
├── 21045 — Malignant tumor + bone graft (includes graft harvest)
├── 21046 — Benign tumor; intraoral osteotomy
└── 21047 — Benign tumor; extra-oral osteotomy

Mandible — Contouring / Exostosis:
├── 21029 — Removal by contouring of benign tumor (eg, fibrous dysplasia)
└── 21031 — Removal of exostosis, maxilla or mandible (torus)

Mandibular Reconstruction — Implants:
├── 21248 — Reconstruction mandible/maxilla, endosteal implant, partial
└── 21249 — Reconstruction mandible/maxilla, endosteal implant, complete

Bone Graft Codes (separately reportable with [[21025]] if performed):
├── 20900 — Bone graft, minor/small
└── 20902 — Bone graft, major/large

Frequently Paired — Soft Tissue I&D:
├── 41800 — Drainage of abscess, cyst, hematoma — dentoalveolar structures
├── 41805 — Removal of embedded foreign body from dentoalveolar structures; soft tissue
└── 40800 — Drainage of abscess; vestibule of mouth, simple

Airway:
└── 31600 — Tracheotomy, planned (separately reportable if performed)

Wound Debridement (soft tissue only — not bone):
├── 97597 — Debridement, open wound; first 20 sq cm
└── 97598 — Debridement, open wound; each additional 20 sq cm

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🗂️ ICD-10-PCS Context (Inpatient Coding)

Inpatient Coder Note (CIC Relevance)

In the inpatient acute care setting, 21025 is not assigned. All procedures are coded in ICD-10-PCS. Mandibular sequestrectomy or bone excision for osteomyelitis maps to the Excision root operation — cutting out or off, without replacement, a portion of a body part.

ICD-10-PCS Root Operation — Excision of Mandible for Osteomyelitis

Axis	Value
Section	0 – Medical & Surgical
Body System	N – Head and Facial Bones
Root Operation	B – Excision (removing a portion of mandibular bone)
Body Part	B – Mandible, Right / C – Mandible, Left
Approach	0 – Open
Device	Z – No Device
Qualifier	X – Diagnostic (if tissue sent for biopsy/culture) or Z – No Qualifier

Excision (B) vs. Resection (T) — Osteomyelitis Context

• Excision (B) — Partial removal of mandibular bone; applies to the vast majority of 21025 cases (sequestrectomy, saucerization, limited mandibulectomy for osteomyelitis)
• Resection (T) — Complete removal of the entire mandible or a named, complete bony unit; reserved for near-total or total mandibulectomy for extensive Stage 3 ORN/MRONJ — rare and typically combined with reconstruction coding

Qualifier: Diagnostic (X) vs. No Qualifier (Z)

When bone is excised primarily for pathologic/culture diagnosis (e.g., to rule out malignancy, confirm osteomyelitis organism), use qualifier X – Diagnostic. When excision is primarily therapeutic (removal of necrotic bone to treat osteomyelitis), use qualifier Z – No Qualifier. If both purposes are served simultaneously (diagnostic biopsy + therapeutic debridement), use Z and document the therapeutic intent as primary per ICD-10-PCS guideline B3.4a.

Additional PCS Codes for a Complex 21025-Equivalent Case

ICD-10-PCS Code Element	Purpose
Excision, Mandible, Right or Left — Open	Primary sequestrectomy / debridement
Excision, Bone (iliac crest or rib) — if bone graft harvested	Donor site (separately coded)
Replacement, Mandible — if graft placed at recipient site	Bone graft inset (if performed)
Insertion, Drainage Device — if drain placed	Drain placement (coded separately in PCS if substantial)
Drainage, Mouth — if concomitant intraoral abscess drained	Soft tissue I&D component

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📝 Coding Examples

Example 1 — Chronic Mandibular Osteomyelitis with Sequestrectomy (Oral Maxillofacial Surgery)

Clinical Scenario: Patient with poorly controlled type 2 diabetes presents with a 2-month history of left mandibular pain, trismus, and intraoral fistula with purulent drainage. CT shows cortical destruction and sequestrum formation at the left mandibular body. Taken to OR: left vestibular incision, mucoperiosteal flap elevated, sequestrum (1.5 cm fragment of necrotic cortical bone) removed with periosteal elevator, cavity saucerized with rongeurs and bur, copiously irrigated, primary closure achieved. Bone and soft tissue cultures obtained.

CPT Code:

• 21025 — Excision of bone, mandible; osteomyelitis

ICD-10-CM:

• M27.2 — Inflammatory conditions of jaws (principal — chronic suppurative osteomyelitis of mandible)
• E11.9 — Type 2 diabetes mellitus without complications (HCC 19)
• K05.30 — Chronic periodontitis, unspecified (contributing etiology)

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Example 2 — MRONJ Stage 2, Bisphosphonate-Related (Oncology / OMS)

Clinical Scenario: 68-year-old female with metastatic breast cancer on monthly IV zoledronic acid for 3 years. Presents with Stage 2 MRONJ of the right posterior mandible — exposed necrotic bone (2 cm), pain, purulent discharge, failed conservative management. OR: right posterior mandibular sequestrectomy, necrotic bone excised to bleeding margins, primary mucosal closure. Culture: Actinomyces israelii.

CPT Code:

• 21025 — Excision of bone, mandible; osteomyelitis/bone abscess (MRONJ)

ICD-10-CM:

• M87.18 — Osteonecrosis due to drugs, other bone (mandible) — principal
• T50.994A — Adverse effect of other drugs affecting uric acid metabolism, initial encounter (bisphosphonate adverse effect)
• C79.51 — Secondary malignant neoplasm of bone (HCC 11 — bone mets, indication for zoledronic acid)
• C50.919 — Malignant neoplasm of breast, unspecified (HCC 12 — primary cancer)

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Example 3 — Osteoradionecrosis, Marx Stage II (Head & Neck / Otolaryngology)

Clinical Scenario: 55-year-old male with prior floor of mouth SCC treated with chemoradiation (72 Gy) 4 years ago, now with Stage II ORN of the left mandibular body. After 30 sessions of HBO with inadequate response, taken to OR for transoral debridement: mucoperiosteal flap elevated, necrotic cortical and medullary bone removed to viable margins bilaterally within the body segment, saucerization performed, primary closure. No segmental resection required.

CPT Code:

• 21025 — Excision of bone, mandible; osteomyelitis/abscess (ORN)
• (HBO sessions coded separately — 99183 per session; outside surgical global)

ICD-10-CM:

• M87.38 — Other secondary osteonecrosis, other bones (ORN — principal)
• T66.XXXA — Radiation sickness, unspecified, initial encounter (etiology — radiation)
• Y84.2 — Radiological procedure as cause of abnormal reaction (external cause)
• Z85.819 — Personal history of malignant neoplasm (if disease-free; use C04.9 if still under active treatment)

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Example 4 — Acute Jaw Abscess with Bone Involvement and Sepsis (Inpatient)

Clinical Scenario: 42-year-old immunocompromised patient (HIV-positive, CD4 < 200) admitted with right facial swelling, fever, tachycardia, elevated WBC 22k, elevated lactate. CT shows right mandibular body bone abscess with cortical destruction and adjacent soft tissue infection. ID consult documents sepsis secondary to mandibular bone abscess. Emergency OR: right submandibular approach, infected bone debrided, abscess drained, wound irrigated, drain placed.

CPT Codes:

• 21025 — Excision of bone, mandible; bone abscess (primary surgical procedure)
• 41800 — Drainage of abscess, dentoalveolar structures (if soft tissue abscess also drained as distinct component — modifier -51) (verify NCCI)

ICD-10-CM:

• A41.9 — Sepsis, unspecified (principal — per Sepsis-3/Sepsis sequencing guidelines when sepsis documented) (HCC 2 / MCC)
• M27.2 — Inflammatory conditions of jaws (bone abscess — underlying infection source)
• B20 — HIV disease (HCC 1)
• D84.9 — Immunodeficiency, unspecified (if HIV coding is not used)

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Example 5 — MRONJ Stage 3 Requiring Segmental Resection (Complex Case — Code Selection Discussion)

Clinical Scenario: 72-year-old male with prostate cancer on long-term denosumab. Stage 3 MRONJ with pathologic fracture of right mandibular angle and orocutaneous fistula. Segmental mandibulectomy (angle to body, 5 cm) performed with primary soft tissue closure. No bone graft placed at this session — staged reconstruction planned.

CPT Codes:

• 21025 with modifier -22 — Excision of bone, mandible; Stage 3 MRONJ with pathologic fracture and segmental resection; significantly increased complexity
• (Note: Some providers may argue 21044 is appropriate if the extent approaches malignant tumor-level resection — key distinction is etiology: MRONJ/inflammatory → 21025; malignant neoplasm → 21044/21045. Document clearly.)

ICD-10-CM:

• M87.18 — Osteonecrosis due to drugs, other bone (mandible) (principal)
• T50.994A — Adverse effect: other specified systemic drugs (denosumab)
• C61 — Malignant neoplasm of prostate (HCC 11 — underlying indication for denosumab)
• M84.68XA — Pathological fracture in other disease, other site, initial encounter for fracture (pathologic fracture at MRONJ site)

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Example 6 — Return to OR During Global Period (Wound Breakdown / Re-Debridement)

Clinical Scenario: Patient who underwent 21025 for mandibular osteomyelitis 3 weeks ago returns with wound dehiscence and recurrent purulent drainage at the operative site. Taken back to OR for re-debridement of mandibular wound — additional necrotic bone removed, re-irrigated, wound left open for secondary healing.

CPT Code:

• 21025 with modifier -78 — Return to OR for related procedure during the postoperative period (within 90-day global)

ICD-10-CM:

• M86.68 — Other chronic osteomyelitis, other bones (persistent/recurrent)
• T81.31XA — Disruption of external operation wound (wound dehiscence, initial)
• Underlying original diagnosis (e.g., M27.2)

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⚠️ Common Coding Pitfalls

• 21025 vs. 21044/21045 — etiology is everything: 21025 is for infection/inflammation/necrosis (osteomyelitis, abscess, ORN, MRONJ). 21044 and 21045 are for malignant neoplasm. The operative report’s clinical indication — not the extent of bone removed — determines code selection. Misassigning 21044 for ORN is a compliance risk; under-assigning 21025 for a malignancy resection fails to capture appropriate reimbursement.
• Do not assign 21025 for benign odontogenic tumor debridement: Procedures for ameloblastoma, odontogenic cysts, or other benign neoplasms — even when inflammatory components are present — should be coded with 21040, 21041, 21046, or 21047 depending on approach and complexity.
• ORN vs. malignant recurrence: Always confirm biopsy results before coding. If pathology returns malignant → recode to 21044/21045. If pathology confirms necrosis without malignancy → 21025 stands. Blind coding without pathology review is a compliance vulnerability in ORN cases.
• MRONJ staging drives code complexity: Stage 1 (conservative) → no surgical code. Stage 2 (limited debridement) → 21025. Stage 3 with pathologic fracture or segmental resection → 21025 with modifier 22 or evaluate 21044/21045 if malignant context. Match the code to the documented extent of surgery.
• Bone graft with 21025: Unlike 21045, the bone graft harvest is not bundled in 21025. If an autologous bone graft was placed in the same session, 20900 or 20902 may be separately reportable — verify NCCI and payer policy, document distinctly.
• Soft tissue debridement codes (97597, 97598) are not equivalent: These are wound care codes appropriate for superficial wound debridement. When mandibular bone is excised surgically under anesthesia, 21025 is always the correct, more specific code.
• Inpatient coding: Never assign 21025 for an inpatient acute care stay. Use ICD-10-PCS root operation Excision (B), body system N (Head and Facial Bones), body part Mandible Right (B) or Left (C), approach Open (0).
• HCC capture for MRONJ: In patients on bisphosphonates for malignant indications (bone mets, myeloma), the underlying malignancy (C90.00, C79.51, C61, etc.) carries significant HCC weight. Always code the active underlying condition alongside the MRONJ.
• Modifier -22 documentation discipline: For complex multi-stage ORN resections or extensive MRONJ procedures, modifier -22 is defensible — but requires specific operative note language describing the exceptional difficulty encountered (vascular changes, indistinct tissue planes, pathologic fracture risk, prior radiation changes). A generic mention of “complex” is insufficient. Attach a cover letter to the claim.

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📚 Brief Source References

^{AMA CPT Professional Edition 2025, codes 21025–21026 and musculoskeletal head section guidelines CMS Medicare Physician Fee Schedule Final Rule 2025 – Work RVU and payment indicator files (www.cms.gov/Medicare/Medicare-Fee-for-Service-Payment/PhysicianFeeSched) CMS NCCI Policy Manual for Medicare Services, Chapter 9: Surgery – Musculoskeletal System, 2025 CMS MS-DRG Definitions Manual v41 FY2024 – DRGs 154–156, 168–170, 539–541 ICD-10-PCS Official Guidelines for Coding and Reporting FY2025, Section B3 – Root Operations (Excision B3.4a Diagnostic qualifier) ICD-10-CM Official Guidelines for Coding and Reporting FY2025, Section I.C.2 (Neoplasms), I.C.19 (Adverse Effects) American Association of Oral and Maxillofacial Surgeons (AAOMS). Medication-Related Osteonecrosis of the Jaw – 2022 Update. AAOMS Position Paper 2022 Marx RE. Osteoradionecrosis: A new concept of its pathophysiology. J Oral Maxillofac Surg 1983;41(5):283–288 AAPC CPC/CIC Study Guide – Musculoskeletal Surgery: Head; Integumentary and Infectious chapters}