Crystal's MCW Coder Hub👩🏾⚕️ CPT Code 31237 — Nasal/Sinus Endoscopy, Surgical; with Biopsy, Polypectomy or Debridement (Separate Procedure)
🏥 Code Description
CPT 31237 describes a surgical nasal/sinus endoscopy performed with one or more of the following: biopsy, polypectomy, or debridement. This procedure is performed using a rigid or flexible nasal endoscope introduced into the nasal cavity and/or sinus passages. The surgeon directly visualizes the nasal mucosa, turbinates, sinus ostia, and adjacent structures to obtain tissue samples, remove polyps, or debride necrotic or inflammatory tissue.
This is designated as a separate procedure, meaning it is considered a component of more extensive nasal/sinus endoscopic procedures when performed at the same session. It may be reported independently only when it is the sole endoscopic service performed, or when performed at a distinctly separate site not addressed by the primary endoscopy code.
Anatomical Considerations
The procedure involves endoscopic access to:
- Nasal cavity — including the inferior, middle, and superior turbinates, nasal septum, and mucosal lining
- Middle meatus — the key drainage pathway for the maxillary, anterior ethmoid, and frontal sinuses
- Sinus ostia — natural openings of the paranasal sinuses
- Nasopharynx (if scope is advanced posteriorly)
Tip
Biopsies are typically taken from suspicious mucosal lesions, granulomatous tissue, masses, or ulcerative lesions. Polypectomy targets inflammatory nasal polyps arising most commonly from the middle meatus or ethmoid region. debridement removes crusting, fibrin, necrotic tissue, or post-operative debris.
Procedure Details
The patient is typically placed supine with the head in a neutral or slightly extended position. After administration of topical vasoconstrictors and anesthesia (either topical/local or general anesthesia), a nasal endoscope (commonly 0° or 30° rigid scope) is introduced transnasally. The surgeon systematically examines the nasal cavity, inspecting mucosal surfaces, turbinate architecture, and septal integrity. Under direct endoscopic visualization:
- Biopsy — Forceps are passed alongside the endoscope to grasp and excise tissue from the targeted lesion. Hemostasis is achieved with cautery or packing as needed.
- Polypectomy — A microdebrider, suction, or forceps is used to remove polypoid tissue. Care is taken to avoid injury to the lateral nasal wall, orbit, or skull base.
- Debridement — Necrotic, crusted, or infected tissue is mechanically removed to promote healing and improve drainage, commonly performed post-operatively following functional endoscopic sinus surgery (FESS).
wRVU
| Component | Value |
|---|---|
| Work RVU | 3.59 |
| Practice Expense RVU (Facility) | 1.72 |
| Practice Expense RVU (Non-Facility) | 8.43 |
| Malpractice RVU | 0.26 |
| Total RVU (Facility) | 5.57 |
| Total RVU (Non-Facility) | 12.28 |
Assistant Payable
No. An assistant surgeon is not eligible for reimbursement under CPT 31237. This is a unilateral endoscopic procedure performed by the primary surgeon without need for an assistant. Medicare and most commercial payers do not allow assistant surgeon billing for this code.
Bilateral Indicator
Indicator 1 — This procedure can be performed bilaterally. When performed bilaterally in the same operative session, append modifier -50 (Bilateral Procedure). Medicare pays 150% of the unilateral fee when billed with modifier -50 on a single line, or 100% + 50% when billed on two separate lines.
Global Period
010 days — Minor surgery with a 10-day global period. Pre-operative care on the day of and day before the procedure, intraoperative services, and routine post-operative follow-up for 10 days are included in the global package. Separate billing for related E/M services during the global period is not permitted unless a separately identifiable, unrelated problem is addressed (append modifier -24 or -25 as appropriate).
Includes
The following services are bundled into 31237 and may not be separately reported when performed as part of this procedure:
- Diagnostic nasal endoscopy (31231) — the diagnostic scope examination is always included when a surgical endoscopy is performed
- Introduction of the endoscope into the nasal cavity
- Routine hemostasis (cautery, packing) at the biopsy/polypectomy site
- Topical application of vasoconstrictor agents during the procedure
- Nasal endoscopic photography or video documentation
- Standard specimen preparation and handling
Excludes / Unbundling Considerations
When more extensive surgical endoscopy is performed at the same session, 31237 is generally not separately reportable as it is considered a component (“separate procedure” designation). More comprehensive codes that subsume 31237 include:
- 31240 — Nasal/sinus endoscopy, surgical, with concha bullosa resection
- 31253 — Total ethmoidectomy with maxillary antrostomy
- 31254 / 31255 — Ethmoidectomy (partial/total)
- 31256 / 31267 — Maxillary antrostomy with/without tissue removal
- 31276 — Frontal sinus exploration/trephination
- 31287 / 31288 — Sphenoid sinusotomy
- 31290 / 31291 — Frontal sinus surgery (Draf procedures)
Coding Pearl:
If the surgeon performs a 31237 for biopsy at one site and a separate, more extensive sinus procedure (e.g., 31255 ethmoidectomy) at a different, distinct site in the same session, modifier -59 (Distinct Procedural Service) or an -XS modifier (Separate Structure) may be appended to 31237 to bypass NCCI bundling edits — but only if documentation clearly supports the distinct nature of each service.
NCCI Edits (National Correct Coding Initiative)
CPT 31237 is subject to significant bundling under NCCI. The code is bundled with all higher-level sinus endoscopy codes. Key column 1/column 2 relationships:
- 31237 is the column 2 (component) code when paired with most surgical sinus endoscopy codes
- Modifier allowed in most pairings when documentation supports distinct service
- Always query your NCCI edit table prior to billing 31237 alongside other 312xx codes
Common ICD-10-CM Diagnoses Paired with 31237
Nasal Polyps
| Code | Description |
|---|---|
| J33.0 | Polyp of nasal cavity |
| J33.1 | Polypoid sinus degeneration (Woakes’ syndrome) |
| J33.8 | Other polyps of sinus |
| J33.9 | Nasal polyp, unspecified |
Chronic Sinusitis
| Code | Description |
|---|---|
| J32.0 | Chronic maxillary sinusitis |
| J32.1 | Chronic frontal sinusitis |
| J32.2 | Chronic ethmoidal sinusitis |
| J32.3 | Chronic sphenoidal sinusitis |
| J32.4 | Chronic pansinusitis |
| J32.8 | Other chronic sinusitis |
| J32.9 | Chronic sinusitis, unspecified |
Neoplasm (Biopsy Indication)
| Code | Description |
|---|---|
| D14.0 | Benign neoplasm of middle ear, nasal cavity, and accessory sinuses |
| D38.5 | Neoplasm of uncertain behavior of other respiratory organs |
| C30.0 | Malignant neoplasm of nasal cavity |
| C31.0 | Malignant neoplasm of maxillary sinus |
| C31.9 | Malignant neoplasm of accessory sinus, unspecified |
Granulomatous / Inflammatory Conditions
| Code | Description |
|---|---|
| J34.3 | Hypertrophy of nasal turbinates |
| J34.81 | Nasal mucositis (ulcerative) |
| M31.30 | Wegener’s granulomatosis without renal involvement |
| M31.31 | Wegener’s granulomatosis with renal involvement |
| D86.0 | sarcoidosis of lung |
| D86.83 | Sarcoidosis of skin |
Post-Operative Debridement
| Code | Description |
|---|---|
| J95.89 | Other intraoperative and postprocedural complications of respiratory system |
| Z48.89 | Encounter for other specified surgical aftercare |
| Z09 | Encounter for follow-up exam after completed treatment |
HCC (Hierarchical Condition Category)
CPT 31237 itself does not carry an HCC value — HCC is an ICD-10-CM diagnosis-based risk adjustment model used in Medicare Advantage. However, the diagnoses driving the procedure may have HCC relevance:
| Diagnosis | HCC Relevance |
|---|---|
| Nasal polyps (J33.x) | No HCC mapping |
| Chronic sinusitis (J32.x) | No HCC mapping |
| Malignant neoplasm nasal cavity (C30.0) | HCC 12 — Lung and Other Severe Cancers |
| Malignant neoplasm accessory sinus (C31.x) | HCC 12 — Lung and Other Severe Cancers |
| Wegener’s granulomatosis (M31.3x) | HCC 57 — Immune Disorders |
| Sarcoidosis (D86.x) | HCC 112 — Fibrosis of Lung or Other Chronic Lung Disorders |
Coder Note:
Capture all relevant diagnoses driving the procedure to support accurate RAF scoring in Medicare Advantage patients. A biopsy performed for a suspected malignancy with confirmed pathology should be updated to the confirmed malignancy diagnosis once pathology returns.
MS-DRG Relevance
CPT 31237 is primarily an outpatient/ambulatory surgery procedure and does not directly map to an MS-DRG. However, when this procedure is performed in the inpatient setting (uncommon but possible in immunocompromised patients, complex debridement cases, or patients with significant comorbidities), ICD-10-PCS coding applies rather than CPT.
Relevant ICD-10-PCS Roots for Inpatient:
| PCS Root Operation | Code Example | Description |
|---|---|---|
| Excision (biopsy) | 09BK3ZX | Excision of nasal mucosa, percutaneous endoscopic, diagnostic |
| Excision (polypectomy) | 09BK8ZZ | Excision of nasal mucosa, via natural or artificial opening endoscopic |
| Extraction | 09DK8ZZ | Extraction, nasal turbinate, endoscopic |
| Repair/Debridement | 09QK8ZZ | Repair nasal structure, endoscopic |
Associated MS-DRGs (Inpatient, ICD-10-PCS driven):
| MS-DRG | Description | GMLOS |
|---|---|---|
| 153 | Other Ear, Nose, Mouth and Throat O.R. Procedures with MCC | 5.4 |
| 154 | Other Ear, Nose, Mouth and Throat O.R. Procedures with CC | 3.2 |
| 155 | Other Ear, Nose, Mouth and Throat O.R. Procedures without CC/MCC | 1.8 |
| 149 | Dysequilibrium | — |
Important
For inpatient stays involving nasal/sinus endoscopy with concurrent malignancy workup or significant infection (e.g., invasive fungal sinusitis), MCC/CC diagnoses (e.g., sepsis, immunodeficiency, malignancy) will significantly impact DRG assignment and geometric mean LOS.
Code Tree / Nasal Endoscopy Hierarchy
The nasal endoscopy CPT family follows a ladder structure — each code builds upon the previous, and the lesser procedures are bundled into the greater:
31231 — Diagnostic nasal endoscopy (BASE; always included in all surgical endoscopies)
│
├── 31237 — Surgical; with biopsy, polypectomy, or debridement ← YOU ARE HERE
│
├── 31238 — Surgical; with control of nasal hemorrhage
│
├── 31239 — Surgical; with dacryocystorhinostomy
│
├── 31240 — Surgical; with concha bullosa resection
│
├── 31253 — Surgical; total ethmoidectomy with maxillary antrostomy, bilateral
│
├── 31254 — Surgical; with ethmoidectomy, partial (anterior)
│
├── 31255 — Surgical; with ethmoidectomy, total (anterior and posterior)
│
├── 31256 — Surgical; with maxillary antrostomy
│
├── 31257 — Surgical; with maxillary antrostomy and removal of tissue
│
├── 31259 — Surgical; with total ethmoidectomy, maxillary antrostomy and removal of tissue from maxillary sinus
│
├── 31267 — Surgical; with maxillary antrostomy and removal of tissue
│
├── 31276 — Surgical; with frontal sinus exploration
│
├── 31287 — Surgical; with sphenoid sinusotomy
│
├── 31288 — Surgical; with sphenoid sinusotomy and removal of tissue
│
└── 31290-31294 — Frontal sinus procedures (Draf II/III)
Coding Examples
Example 1 — Nasal Polyp Removal, Outpatient, Unilateral
Operative Note Summary: A 52-year-old male with chronic bilateral nasal obstruction and known nasal polyposis presents for endoscopic nasal polypectomy. Under general anesthesia, a 0° rigid nasal endoscope was introduced into the right nasal cavity. Multiple inflammatory polyps were identified in the right middle meatus and removed using a microdebrider. No sinus surgery was performed. Left side not entered.
CPT: 31237
ICD-10-CM: J33.0
Modifier: None (unilateral)
Example 2 — Bilateral Nasal Polypectomy
Operative Note Summary: Same patient as above, but polyps were addressed bilaterally in the same session — right and left middle meatal polyps removed endoscopically without sinus surgery.
CPT: 31237-50
ICD-10-CM: J33.0
Modifier: -50 (Bilateral)
Billing Note: Report on a single line with modifier -50 for Medicare; some commercial payers require two lines (31237-RT and 31237-LT).
Example 3 — Biopsy of Suspicious Nasal Mass
Operative Note Summary: A 67-year-old female referred for evaluation of a right nasal cavity mass noted on MRI. Endoscopic exam revealed a firm, vascular mass arising from the right nasal septum. Multiple biopsies were obtained using cupped forceps. Final pathology: squamous cell carcinoma.
CPT: 31237
ICD-10-CM: C30.0 (update from D38.5 or R09.89 once pathology confirmed)
HCC Impact: HCC 12 — capture this for RAF in Medicare Advantage patients
Modifier: None
Example 4 — Post-Operative Debridement After FESS
Operative Note Summary: A 44-year-old female returns 10 days after bilateral FESS (31254-50, 31256-50) for post-operative endoscopic debridement. Under topical anesthesia, the endoscope was introduced bilaterally and crusting, fibrinous debris, and synechia were debrided from both ethmoid cavities and maxillary antrostomy sites.
CPT: 31237-50
ICD-10-CM: Z48.89 (post-op aftercare), J32.4 (chronic pansinusitis, underlying condition)
Global Period Note: If within the global period of the prior FESS codes, this debridement may be bundled unless it meets the threshold for a separately reportable service. Append modifier -78 (Unplanned Return to OR During Global Period) if performed in the OR setting, or modifier -79 (Unrelated Procedure During Global Period) if clinically justified as unrelated. Many payers consider routine post-FESS debridement as included in the FESS global — check payer policy.
Example 5 — Biopsy with Concurrent Ethmoidectomy (Unbundling Scenario)
Operative Note Summary: A 58-year-old male with chronic pansinusitis and a right nasal cavity lesion. Surgeon performed a right total ethmoidectomy (31255-RT) and separately biopsied a distinct lesion on the left nasal septum (31237-LT).
CPT: 31255-RT and 31237-59-LT (or 31237-XS-LT)
ICD-10-CM: J32.4, D14.0 (or appropriate code for lesion)
NCCI Note: 31237 is bundled with 31255; modifier -59 or -XS is required to bypass the edit. Documentation must clearly support that the biopsy was performed at a separate and distinct anatomical site from the ethmoidectomy. If the biopsy was taken from within the ethmoid cavity being operated on, it is not separately reportable.
Documentation Requirements
To support billing of 31237, the operative report must clearly document:
- Indication for the procedure (symptoms, clinical findings, prior imaging)
- Type of anesthesia (topical, local, monitored anesthesia care, or general)
- Scope used (rigid vs. flexible, degree)
- Site(s) visualized — all structures examined should be described
- Specific procedure performed — biopsy (site, method, number of specimens), polypectomy (side, location, method), or debridement (location, extent, type of material removed)
- Laterality — right, left, or bilateral
- Pathology submission — specimen labeled and sent if biopsy obtained
- Hemostasis method
- Findings — description of mucosa, polyps, lesions, patency of ostia
Reimbursement Notes
- Medicare 2025 national average payment (facility): approximately 210
- Medicare 2025 national average payment (non-facility/office): approximately 480
- Anesthesia: Generally MAC or general anesthesia is supported; topical-only cases may face scrutiny for facility fee billing
- Prior authorization is frequently required by commercial payers for elective polypectomy
- Some payers require failed medical management documentation (e.g., intranasal corticosteroids, nasal saline irrigation) prior to authorizing surgical polypectomy