31259

🧬 CPT Code 31259:

Plain‑language description

CPT 31259 describes a surgical endoscopic procedure in which the surgeon performs a total ethmoidectomy (both anterior and posterior ethmoid air cells) and a sphenoidotomy with removal of diseased tissue from the sphenoid sinus, all via the nasal passages using nasal/sinus endoscopy.¹ This is typically performed for chronic rhinosinusitis that has failed maximal medical therapy, for extensive polyposis involving the ethmoid and sphenoid sinuses, or for selected neoplastic or skull‑base-adjacent lesions where endoscopic access through the ethmoid and sphenoid is required.¹

The work includes identification and opening of the ethmoid air cells, removal of inflamed or polypoid tissue, entry into the sphenoid sinus, enlargement of the sphenoid ostium, and excision of sphenoid sinus mucosa or tissue as indicated.¹ In many cases, image guidance is used and documented but is separately reportable with an appropriate add‑on code when payer policy permits (not inherent to 31259).⁷

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Key coding attributes

• Code set: 31259 (Current Procedural Terminology - Surgery, Respiratory System, Accessory Sinuses).¹
• Approach: Endoscopic, transnasal, using a nasal endoscope (rigid or occasionally flexible) for visualization.¹
• Extent of sinus work:
  • Total ethmoidectomy (anterior and posterior ethmoid air cells).¹
    • Sphenoidotomy with removal of tissue from the sphenoid sinus (e.g., mucosa, polyps, diseased tissue, sometimes tumor debulking when appropriate).¹
• Typical anesthesia: General anesthesia in operating room setting, due to complexity and need for hemostasis and visualization.⁵
• Typical setting: Hospital outpatient department or ambulatory surgery center; can also be done in inpatient OR for complex disease or when combined with other procedures (e.g., skull base surgery, neurosurgery).⁴

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Clinical indications and medical necessity

Common indications (documentation should clearly support one or more):

• Chronic rhinosinusitis involving ethmoid and sphenoid sinuses (e.g., J32.2, J32.3, J32.4) with persistent symptoms despite maximal medical management (nasal steroids, saline irrigations, culture‑directed antibiotics, etc.).³
• Extensive nasal polyposis or polypoidal degeneration obstructing ethmoid and sphenoid sinuses (e.g., J33.0, J33.1).³
• Recurrent acute rhinosinusitis with radiographic evidence of ethmoid/sphenoid disease and failure of appropriate medical therapy, as outlined by payer sinus surgery policies.⁵
• Complications of sinus disease (e.g., mucocele, fungal sinusitis, or selected neoplasms) requiring total ethmoidectomy and sphenoid tissue removal for drainage or access.⁵
• Adjunctive access for endoscopic endonasal skull base or pituitary surgery, when the ENT surgeon performs the ethmoid and sphenoid work while neurosurgery performs the intracranial component (in some of these cases, unlisted codes such as 31299 or neurosurgical codes may be more appropriate depending on the exact distribution of work).²

Documentation hallmarks:

• Laterality (left, right, or bilateral).¹
• Pre‑operative imaging correlated with intra‑operative findings (CT, MRI if relevant).⁵
• Description of the extent of ethmoidectomy (clearly stating “total” or specifying anterior and posterior ethmoid cells removed).¹
• Description of sphenoidotomy (creation or enlargement of sphenoid ostium) and explicit notation of tissue removal from the sphenoid sinus (e.g., mucosa, polypoid tissue, mass tissue).¹

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Code tree and related sinus endoscopy codes

Ethmoid and sphenoid endoscopy grouping

Accessory Sinus Endoscopy (Selected)

- []  Nasal/sinus endoscopy, surgical; with ethmoidectomy, partial (anterior).
- []  Ethmoidectomy, anterior; total.
- []  Nasal/sinus endoscopy, surgical; with maxillary antrostomy.
- []  Nasal/sinus endoscopy, surgical; with ethmoidectomy (total, anterior and posterior).
- []  Nasal/sinus endoscopy, surgical; with total ethmoidectomy and sphenoidotomy, including removal of tissue from the sphenoid sinus.

- []  Nasal/sinus endoscopy, surgical; with sphenoidotomy.
- []  Nasal/sinus endoscopy, surgical; with sphenoidotomy; with removal of tissue from sphenoid sinus.

- []  Nasal/sinus endoscopy, surgical; frontal sinus exploration, including removal of tissue from frontal sinus, when performed.
- []+ Other endoscopic sinus codes (e.g., maxillary antrostomy with tissue removal).

• 31257 is used when a total ethmoidectomy (anterior and posterior) is performed without sphenoidotomy and sphenoid tissue removal.¹

• 31287/31288 describe sphenoidotomy (with or without tissue removal) but do not include total ethmoidectomy; if both total ethmoid and sphenoid tissue removal are done in the same side, 31259 is normally chosen instead of separately reporting 31257 plus 31288.¹

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Includes and excludes (conceptual)

Included in 31259 (inherent work)

• Use of nasal endoscope and standard endoscopic instrumentation.¹

• Total ethmoidectomy (anterior and posterior ethmoid air cells), including removal of polyps and diseased tissue within those cells.¹

• Sphenoidotomy and enlargement of sphenoid sinus ostium on the treated side(s).¹

• Removal of tissue from the sphenoid sinus (e.g., mucosa, polyps, inflammatory or fungal debris), when performed.¹

• Hemostasis, packing, and typical postoperative debridement expectations (not separately billable procedures).⁵

Commonly excluded/separately reportable services

• Septoplasty (e.g., 30520) when medically necessary and not considered integral by payer; documentation should show separate indication (e.g., septal deviation causing obstruction, access alone may be bundled by some payers).⁸

• Turbinate reduction (e.g., 30130, 30140, 30115) when performed beyond limited out‑fracture or minor reduction for visualization only.⁵

• Frontal sinusotomy (e.g., 31276) when frontal sinus exploration and tissue removal are performed; this work is not inherent to 31259.¹

• Stereotactic image guidance, when billed separately with the appropriate add‑on code per payer guidelines.⁷

• True skull base tumor resection and reconstruction; these may instead require unlisted codes such as 31299 and neurosurgical codes like 62165, often with -62 or -80/-AS modifiers depending on co‑surgeon arrangements.²⁸

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Modifiers

Common modifiers associated with 31259 (always verify payer‑specific rules):⁴⁷

• Increased Procedural Services: For substantially greater work (e.g., severe scarring, revision FESS, extensive fungal disease); op note must clearly support added complexity.

• Bilateral Procedure: When the procedure (total ethmoidectomy plus sphenoidotomy with tissue removal) is performed on both sides in the same session and payer recognizes bilateral reporting.

• Multiple Procedures: When 31259 is performed with other unrelated or additional sinus or nasal procedures in the same operative session.

• -XE / -XS - Distinct procedural service / separate structure: When a distinct sinus procedure is performed on a separate anatomic site that might otherwise be bundled; documentation must clearly support distinctness.

• -LT / -RT - To report laterality when required by payer (e.g., unilateral 31259 left or right).

• -76 / -77 - Repeat procedures in the same session or postoperative period by same or another physician.

• -78 - Return to OR for related procedure during postoperative period.

• -79 - Return to OR for unrelated procedure during - [].

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RVU, payment, and assistant at surgery

Approximate RBRVS characteristics (you will want to plug in your local fee schedule):

• Work RVU: approximately 5.0 (mid‑to‑high range sinus surgery; confirm with current CMS Physician Fee Schedule).⁴

• Facility payment differentials: National commercial payer data show a wide range of reimbursement for 31259 when billed by facilities, reflecting differences in contracts and geography (from hundreds to several thousand USD for ASC/hospital claims).⁴

Assistant at surgery:

• ACS “Physicians as Assistants at Surgery” tables generally classify sinus procedures like 31259 as “sometimes” requiring an assistant, depending on complexity, teaching environment, and institutional policy.¹⁰

• Payers may permit assistant surgeon payment when documentation supports the need (e.g., complex anatomy, extensive disease, skull base proximity) and local coverage policy does not prohibit it.¹⁰

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ICD‑10‑CM linkage and HCC considerations

Common non‑HCC sinus diagnoses for 31259

• J32.2 - Chronic ethmoidal sinusitis.³

• J32.3 - Chronic sphenoidal sinusitis.³

• J32.4 - Chronic pansinusitis (when multiple sinuses including ethmoid and sphenoid are involved).³

• J33.0 - Polyp of nasal cavity (when polyps obstruct access and cause chronic rhinosinusitis symptoms).³

• J33.1 - Polypoidal sinus degeneration (e.g., extensive polypoid disease in ethmoid/sphenoid).³

Note

These inflammatory codes generally do not map to HCC categories in CMS‑HCC models, though they can still contribute to utilization and quality metrics.⁹

Malignancy‑related diagnoses (HCC‑relevant)

• C31.1 - Malignant neoplasm of ethmoidal sinus.³⁶

• C31.3 - Malignant neoplasm of sphenoid sinus.³⁶

The C31.x malignant neoplasm codes map to solid tumor HCCs in many CMS‑HCC models (check the exact revision your organization uses, e.g., v24).³⁹ Accurate linkage of 31259 with these codes requires clear documentation that the procedure is related to management or access for the malignancy (e.g., tumor debulking, endoscopic approach for resection, drainage of tumor‑related mucocele).²

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MS‑DRG and inpatient considerations

Although 31259 is often an outpatient code, when performed during an inpatient stay it can be a significant OR procedure for MS‑DRG assignment:

• MDC: 3 (Diseases and Disorders of the Ear, Nose, Mouth, and Throat).⁹

• Typical MS‑DRGs used by many groupers for sinus and mastoid procedures include:

  • 136 - Sinus and mastoid procedures with CC.⁹

  • 137 - Sinus and mastoid procedures without CC/MCC.⁹

The exact MS‑DRG depends on:

• Principal diagnosis (e.g., chronic sinusitis versus neoplasm).⁹

• Presence/absence of CC/MCC diagnoses documented during the admission.⁹

• Combination with other major procedures performed in the same stay (e.g., neurosurgical procedures may shift the case to a different MDC/DRG family).⁹

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Coding examples

Example 1 - Bilateral total ethmoidectomy and sphenoid tissue removal for chronic pansinusitis

• Scenario: Patient with chronic pansinusitis and nasal polyposis (J32.4 and J33.0) has failed maximal medical therapy. Endoscopic surgery performed: bilateral total ethmoidectomy and bilateral sphenoidotomy with removal of polypoid tissue from each sphenoid sinus.

• Coding:

  • 31259 (if payer recognizes bilateral reporting with modifier []).

  • Linked ICD‑10‑CM: J32.4, J33.0.

• Rationale: Work includes total ethmoidectomy and sphenoidotomy with tissue removal on both sides, matching the descriptor for 31259 with bilateral performance.¹³

Example 2 - Unilateral ethmoid and sphenoid surgery with additional frontal sinusotomy

• Scenario: Right‑sided chronic ethmoid and sphenoid sinusitis with frontal involvement ([ [J32.2]] and J32.3). Surgeon performs right total ethmoidectomy, right sphenoidotomy with tissue removal, and right frontal sinus exploration with tissue removal.

• Coding:

  • 31259-RT - Right total ethmoidectomy and sphenoidotomy with sphenoid tissue removal.

  • 31276-RT-59 - Right frontal sinus exploration with tissue removal (separate sinus, multiple procedure).

  • Linked ICD‑10‑CM: J32.2, J32.3.

• Rationale: 31259 covers ethmoid + sphenoid work, while frontal sinus exploration is coded separately with 31276. Modifiers indicate laterality and multiple procedures.¹

Example 3 - Malignant neoplasm of sphenoid sinus with endoscopic resection

• Scenario: Patient diagnosed with malignant neoplasm of sphenoid sinus (C31.3). ENT and neurosurgery collaborate for endoscopic resection. ENT performs extensive ethmoidectomy and sphenoidotomy with removal/debulking of tumor tissue from sphenoid sinus; neurosurgery performs intracranial tumor portion.

• Coding (simplified ENT perspective, actual coding may vary by institution):

  • 31259 for the total ethmoidectomy and sphenoidotomy with tissue removal performed by ENT.²

  • Possible additional unlisted code 31299 or neurosurgical codes (e.g., 62165) with modifier [] if ENT functions as co‑surgeon on skull base portion, depending on service distribution and payer guidance.²⁸

  • Linked ICD‑10‑CM: C31.3 (HCC‑relevant).

• Rationale: 31259 describes the sinus component, while skull base and intracranial work often require separate coding under unlisted or specific neurosurgical codes with detailed documentation.²⁸

Example 4 - When NOT to use 31259

• Scenario: Surgeon performs bilateral sphenoidotomy with tissue removal but only a partial anterior ethmoidectomy.

• More appropriate coding might be:

  • 31288 - Bilateral sphenoidotomy with specfied tissue removal.

  • 31254 or 31255 - Depending on the extent of anterior ethmoid work (partial vs total anterior).

• Rationale: 31259 requires total ethmoidectomy (anterior and posterior) plus sphenoidotomy with tissue removal. If only partial ethmoidectomy is performed, you do not have the required total ethmoid component for 31259.¹

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Documentation checklist (for coders)

When reviewing op notes for potential 31259 assignment, ensure:

• Surgeon explicitly documents:

  • “Total ethmoidectomy (anterior and posterior)” on the treated side(s).¹

  • “Sphenoidotomy” with clear description of opening or enlarging the sphenoid ostium.¹

  • “Removal of tissue from the sphenoid sinus” (e.g., mucosa, polypoid tissue, tumor), not just inspection or simple opening.¹

• Laterality is specified (left/right/bilateral) and consistent with any imaging and diagnoses.³

• Linked ICD-10 CM diagnoses are fully supported in pre‑op and post‑op documentation (chronicity, location, failure of medical therapy, neoplasm details if applicable).³⁵

• Any additional procedures (septoplasty, turbinate reduction, frontal sinusotomy, image guidance, neurosurgical skull base work) are distinctly described with their own indications so payer edits and bundling rules can be correctly addressed.²⁵⁸

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Post-Operative Care Considerations

Aspect	Considerations
ICU Stay	Typically 1-3 days minimum for monitoring
Flap Monitoring	Hourly checks for first 24-48 hours
Doppler Signals	Document arterial and venous flow
Drain Care	Monitor output, remove when <30cc/day
Nutrition	NPO initially, advance per protocol
Pain Management	Multimodal analgesia
DVT Prophylaxis	Essential due to cancer + immobility
Wound Care	Keep flap moist, avoid pressure
Follow-up	Within 1 week, then per protocol
Speech Therapy	If oral cavity/pharynx involved
Swallow Study	Before oral intake (typically day 7-14)

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Complications to Monitor

Complication	Signs/Symptoms	Coding (if treated)
Flap Failure	Color change, no Doppler signal, cool flap	T81.89, T83.89
Hematoma	Swelling, pain, discoloration	T81.0
Infection	Redness, drainage, fever	T81.4XXA
Dehiscence	Wound separation	T81.3
Necrosis	Tissue death, black eschar	T81.89
Fistula	Saliva leak, drainage	M95.8, K11.4
Stricture	Dysphagia, narrowing	K22.2
Donor Site Complications	Pain, infection, hernia	T81.89

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HCC (Hierarchical Condition Category) Considerations

Note: CPT codes do not determine HCC status. Diagnosis codes determine HCC risk adjustment.

Head and Neck Diagnoses That May Impact HCC:

HCC Category	ICD-10-CM Examples	Risk Score Impact
Head/Neck Cancer	C00-C14, C32, C73	High
Skin Cancer	C44.0, C44.3	Moderate
Carcinoma in Situ	D00.00-D00.02	Moderate
Chronic Conditions	K11.0-K11.9 (Salivary gland)	Low-Moderate
Diabetes with Complications	E11.4x (with neuropathy affecting head/neck)	High
Metastatic Cancer	C77-C79 (to head/neck)	Very High
Trauma	S00-S09 (Head injuries)	Low-Moderate
Burns	T20-T25 (Head/neck burns)	Moderate

Documentation Tips:

• Document cancer stage and status (active, in remission, history of)
• Document chronic conditions that affect flap healing (diabetes, vascular disease)
• Document nutritional status (malnutrition affects flap viability)
• Document smoking status (affects wound healing)
• Document prior radiation therapy (increases complication risk)

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Sources

¹ AAPC Codify - 31259 endoscopy procedures on the accessory sinuses (description and context).
² PubMed Central - Coding and reimbursement for endoscopic endonasal skull base surgery discussions (use of 31299 and sinus codes).
³ AAPC ICD‑10‑CM listing for C31 and J32/J33 sinus codes (official descriptors).
⁴ PayerPrice - Fee schedule and contextual information for 31259.
⁵ Aetna Clinical Policy Bulletin - Sinus surgeries medical necessity overview.
⁶ WHO ICD‑10 browser - C31 malignant neoplasm of accessory sinuses hierarchy.
⁷ MDClarity - 31259 usage, modifiers, and reimbursement discussion.
⁸ AAPC ENT/skull base coding forum threads discussing 31255/31259/31288/30520 versus 62165‑62 usage.
⁹ CMS NCD and MS‑DRG/general ICD‑10 coding guidance documents for grouping and coverage context.
¹⁰ American College of Surgeons - Physicians as Assistants at Surgery (procedure assistant indicators).