31573

🗣️ CPT 31573 — Laryngoscopy, Flexible; With Therapeutic Injection(s), Unilateral

Quick Reference

wRVU: Verify current MPFS¹ | Global Period: 000 (same day) | Assistant Payable: ❌ No | Bilateral Indicator: 1

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📋 Clinical Description

CPT 31573 describes a flexible endoscopic evaluation of the larynx accompanied by a therapeutic injection. The provider inserts a flexible laryngoscope through the nasal cavity to visualize the larynx and vocal cords, then administers an injection—such as a chemodenervation agent (e.g., Botox) or corticosteroid. The injection may be delivered percutaneously through the neck, transorally, or directly through the endoscope’s working channel. This code is distinct from 31574, which is strictly for augmentation (medialization) injections rather than therapeutic medical injections, and distinct from rigid direct laryngoscopy codes.

Spasmodic Dysphonia is a focal neurological movement disorder characterized by involuntary spasms of the laryngeal muscles, leading to voice breaks and strained speech. Without therapeutic chemodenervation (Botox), the patient experiences significant communication impairment. Corticosteroids may similarly be injected for inflammatory lesions like Vocal Cord Polyps or granulomas.

This procedure may be performed in the following clinical contexts:

• Spasmodic dysphonia — Chemodenervation agents are injected into specific laryngeal muscles to block nerve signals and reduce vocal spasms.
• Vocal Cord Granulomas — Corticosteroids are injected directly into the lesion to reduce severe inflammation and promote healing.
• Refractory Chronic Cough — Botox may occasionally be injected to treat severe laryngeal sensory neuropathy or vocal fold motion impairment.
• Paradoxical Vocal Fold Motion (PVFM) — Botox may be used off-label in severe cases to prevent airway compromise during episodic spasms.

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🔬 Anatomical & Procedural Considerations

Modality	Mechanism / Steps	Key Notes
Percutaneous Injection	Needle is inserted through the anterior neck (cricothyroid membrane) into the target laryngeal muscle while visualized internally via the flexible endoscope passed nasally.	Most common approach for Botox injections. Requires precise coordination between the external needle placement and internal scope view.
Transoral Injection	Needle is passed through the mouth using a curved injector while the scope is passed nasally to visualize the target.	Useful when anterior neck anatomy is challenging or obscured.
Via Endoscope Channel	A long, flexible needle is passed directly through the working channel of the therapeutic flexible endoscope.	Requires a specialized therapeutic endoscope with a channel wide enough for the injection apparatus.

Clinical Pearl

The most critical coding distinction for this family of codes is the substance injected and its purpose. If the provider injects Botox or steroids, bill 31573. If the provider injects a bulk-enhancing agent (like Radiesse or Prolaryn) to plump up a paralyzed vocal cord, you must bill 31574 (Laryngoscopy, flexible; with injection(s) for augmentation). Do not mix these up, as their reimbursement rates and medical necessity policies differ significantly.²

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✅ Procedure Includes

• Topical anesthesia of the nasal cavity and/or pharynx
• Insertion of the flexible laryngoscope and full diagnostic evaluation of the larynx
• Preparation of the therapeutic injection
• Administration of the injection (e.g., percutaneous, transoral, or via scope) under direct internal visualization
• Withdrawal of the scope and routine post-procedure observation
• Documentation of laterality and agent used

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❌ Excludes / Do Not Report Together

Code	Description	Relationship to 31573
31575	Laryngoscopy, flexible; diagnostic	Mutually exclusive. A diagnostic flexible laryngoscopy is inherently bundled into the surgical/therapeutic flexible laryngoscopy.
31570	Laryngoscopy, direct, with injection into vocal cord(s), therapeutic	Mutually exclusive. Use 31570 if a rigid direct laryngoscope is used (typically in the OR) rather than a flexible scope.
31574	Laryngoscopy, flexible; with injection(s) for augmentation	Mutually exclusive for the same lesion. 31574 is specifically for vocal fold medialization/augmentation, whereas 31573 is for therapeutic medication administration.
HCPCS J-Codes	Drug supply (e.g., J0585 for Botox)	The supply of the injected drug is separately reportable. Do not bundle the drug supply into the procedure code; bill it on a separate line with the exact units administered.
E/M codes (992xx)	Office visit, any level	Separately reportable only when modifier -25 is appended to the E/M code, documenting a significant, separately identifiable E/M service beyond the routine pre-procedure assessment.

Bundling Alert — Global Period is 000, Not 010

The global period for 31573 is 000 (same day). This means follow-up visits to check voice quality or manage minor side effects on subsequent days are not bundled and can be billed as established patient E/M visits without a global modifier.

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🌳 Code Tree — Surgery: Respiratory System

CPT 31300-31599 Larynx

│
├── 31572-31579 Endoscopy (Flexible)
│ ├── 31572 Laryngoscopy, flexible; with ablation or destruction of lesion(s)... (Global: 000)
│ ├── ▶▶ 31573 ◀◀ Laryngoscopy, flexible; with therapeutic injection(s)... ← YOU ARE HERE (Global: 000)
│ ├── 31574 Laryngoscopy, flexible; with injection(s) for augmentation... (Global: 000)
│ └── 31575 Laryngoscopy, flexible; diagnostic (Global: 000)

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💰 RVU & Reimbursement Profile

Component	Value
Work RVU (wRVU)	Verify against current CMS MPFS
Global Period	000 (same day)
Bilateral Indicator	1 — 150% payment adjustment applies. Bilateral billing is permitted.
Assistant Surgeon	❌ Not payable
Co-Surgeon	❌ Not applicable
Team Surgery	❌ Not applicable
PC/TC Split	❌ No — procedure code only (Indicator 0)
Modifier -51 Exempt	No
Anesthesia	Topical or local infiltration; no separate anesthesia billing expected in the office setting.

Bilateral Billing Rules

31573 has a bilateral indicator of 1. The code description explicitly states it is a unilateral procedure. Therefore, if the provider injects both the left and right vocal cords during the same session, you should append modifier -50 to a single line item (e.g., 31573-50) and double the fee. Medicare will apply the standard 150% bilateral payment reduction.

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🏷️ Modifier Reference

Modifier	Name	When to Apply
-RT	Right Side	Procedure performed on the right vocal cord or right laryngeal structure.
-LT	Left Side	Procedure performed on the left vocal cord or left laryngeal structure.
-50	Bilateral Procedure	Injections performed on both the right and left sides during the same session.
-25	Significant, Separately Identifiable E/M	Applied to the E/M code — not 31573 — when an office visit is performed on the same date; documentation must support a separate evaluation (e.g., assessing a new upper respiratory symptom unrelated to the scheduled Botox).
-51	Multiple Procedures	When 31573 is performed alongside other surgical procedures at the same session; apply to the lower-valued code.
-59	Distinct Procedural Service	When payers inappropriately bundle 31573 with another procedure; documents distinct anatomic site or independent service.
-52	Reduced Services	Procedure partially completed — e.g., scope inserted but injection aborted due to patient intolerance.
-53	Discontinued Procedure	Procedure stopped due to patient safety concern (e.g., severe laryngospasm).

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🩺 Common ICD-10-CM Pairings

Spasmodic Dysphonia & Voice Disorders

ICD-10 Code	Description	HCC?	Clinical Notes
G24.8	Other dystonia	❌ No	The primary ICD-10 code for Spasmodic Dysphonia.
J38.01	Paralysis of vocal cords and larynx, unilateral	❌ No	Used if injecting for unilateral paralysis issues, though augmentation (31574) is more common for this diagnosis.
J38.02	Paralysis of vocal cords and larynx, bilateral	❌ No	Use with modifier -50 if treating both sides.
R49.0	Dysphonia	❌ No	Primary symptom code; use if the specific etiology (like dystonia) is not yet definitively documented.

Vocal Cord Lesions

ICD-10 Code	Description	HCC?	Clinical Notes
J38.1	Vocal cord and false vocal cord polyp	❌ No	Common diagnosis when injecting corticosteroids.
J38.2	Nodules of vocal cords	❌ No	Used when injecting anti-inflammatories.
J38.3	Other diseases of vocal cords	❌ No	Catch-all for granulomas or other unlisted benign lesions of the vocal cords requiring steroid injection.

Coding Specificity Reminder

Laterality is paramount. While G24.8 does not require laterality, codes under the J38.0 family (Paralysis) do. Furthermore, the procedural code itself is strictly unilateral. Ensure the operative note specifically dictates which vocal cord (Left, Right, or Bilateral) was injected to support your -RT, -LT, or -50 modifiers.

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🏥 MS-DRG Considerations (Inpatient)

Inpatient Coding Reminder

CPT 31573 is performed primarily in the outpatient / office / ASC setting. There are no routine MS-DRG assignments for this procedure — inpatient admission for isolated flexible laryngoscopy with injection would not be supported by any payer or utilization review body. If a patient undergoing an inpatient admission for an unrelated diagnosis also has this procedure performed, an ICD-10-PCS code may be assigned for completeness, but it will have no meaningful impact on DRG grouping.

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🔧 ICD-10-PCS Equivalents (Inpatient Facility Coding)

Note

PCS codes for this procedure belong to the Administration section (3). The root operation is always Introduction (0). The coding path depends on the approach (percutaneous vs. via natural opening) and the substance injected.

PCS Code	Full Description	Applicable Modality
3E0F7GC	Introduction of Other Therapeutic Substance into Respiratory Tract, Via Natural or Artificial Opening	Chemodenervation (Botox) delivered transorally or via endoscope channel
3E0F3GC	Introduction of Other Therapeutic Substance into Respiratory Tract, Percutaneous Approach	Chemodenervation (Botox) delivered percutaneously through the neck
3E0F73Z	Introduction of Anti-inflammatory into Respiratory Tract, Via Natural or Artificial Opening	Corticosteroids delivered transorally or via endoscope channel
3E0F33Z	Introduction of Anti-inflammatory into Respiratory Tract, Percutaneous Approach	Corticosteroids delivered percutaneously

PCS Character Analysis — 3E0F7GC

Position	Character	Value	Definition
1	Section	3	Administration
2	Body System	E	Physiological Systems and Anatomical Regions
3	Root Operation	0	Introduction (Putting in or on a therapeutic, diagnostic, nutritional, physiological, or prophylactic substance)
4	Body Part	F	Respiratory Tract
5	Approach	7	Via Natural or Artificial Opening (Transoral / Transnasal)
6	Substance	G	Other Therapeutic Substance (Used for Botulinum Toxin)
7	Qualifier	C	Other Therapeutic Substance

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📝 Coding Examples

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Example 1 — Office: Unilateral Percutaneous Botox Injection for Spasmodic Dysphonia

Clinical Scenario: A 45-year-old female presents to the otolaryngology clinic for her scheduled Botox injection to treat spasmodic dysphonia. The provider applies topical lidocaine to the nasal passages and inserts the flexible laryngoscope. The true vocal cords are visualized. While observing internally, the provider inserts a needle percutaneously through the cricothyroid membrane and injects 2.5 units of Botulinum Toxin Type A (Botox) into the right thyroarytenoid muscle. The patient tolerated the procedure well. No separate E/M was documented.

Field	Code	Rationale
CPT 1	31573-RT	Laryngoscopy, flexible, with therapeutic injection. -RT indicates the right vocal cord was treated.
HCPCS	J0585 x 3	Injection, onabotulinumtoxinA, 1 unit. Billed for the specific units utilized (round up to the nearest unit, plus any appropriately documented discarded waste if applicable using the JW/JZ modifiers).
PDx	G24.8	Other dystonia (Spasmodic dysphonia) supports the medical necessity of the chemodenervation.

Note

The diagnostic portion of the flexible laryngoscopy is bundled into 31573 and cannot be billed separately. The drug (J0585) is billed separately on the claim.

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Example 2 — Office: Bilateral Steroid Injection with Same-Day E/M

Clinical Scenario: A 55-year-old male with a history of vocal cord nodules presents for a scheduled flexible laryngoscopy and steroid injection. Prior to the procedure, the patient complains of new, acute left ear pain and hearing loss that began two days ago. The provider performs a separate, detailed exam of the ears, diagnosing acute left otitis media and prescribing antibiotics. The provider then proceeds with the flexible laryngoscopy, injecting Kenalog (corticosteroid) bilaterally into the vocal cord nodules transorally.

Field	Code	Rationale
CPT 1	99213-25	A significant, separately identifiable evaluation was performed for the new ear pain.
CPT 2	31573-50	Flexible laryngoscopy with therapeutic injection. Modifier -50 is applied because the injections were bilateral.
HCPCS	J3301	Injection, triamcinolone acetonide (Kenalog), per 10 mg.
PDx	H66.92	Otitis media, unspecified, left ear. Linked to the E/M visit.
SDx	J38.2	Nodules of vocal cords. Linked to the surgical procedure (31573) and drug.

Warning

The -25 modifier must go on the E/M code. The documentation clearly separates the work done for the acute ear infection from the routine pre-procedure assessment for the vocal cord injections.

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⚠️ Common Coding Pitfalls

• Missing documentation of laterality: The code descriptor explicitly states “unilateral.” If the operative note fails to specify whether the right, left, or both vocal cords were injected, the claim will likely be denied or processed incorrectly. Always append -RT, -LT, or -50.
• Confusing 31573 with 31574: This is a major compliance risk. 31573 is for therapeutic medical injections (Botox, steroids). 31574 is strictly for augmentation injections (bulk-enhancing agents to treat paralysis). Applying the wrong code misrepresents the service and can result in significant overpayments or denials.
• Failing to bill the injected medication: CPT 31573 covers the physician’s work in performing the procedure. It does not include the cost of the drug. If you fail to add the appropriate J-code (e.g., J0585 for Botox) to the claim, the practice loses the reimbursement for the expensive medication.
• Billing a diagnostic scope (31575) alongside 31573: NCCI edits strictly prohibit billing a diagnostic flexible laryngoscopy on the same day as a therapeutic flexible laryngoscopy by the same provider. The diagnostic look is considered the first step of the therapeutic procedure.
• Reporting 31573 for rigid endoscopy: If the patient is taken to the operating room and a direct, rigid laryngoscope is used to suspend the airway and perform the injection, you must bill 31570 (or 31571 if an operating microscope is used), not 31573.

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📎 Sources

¹ CMS MPFS Relative Value Files
² AMA CPT Professional Edition
³ ICD-10-CM Official Guidelines for Coding and Reporting
⁴ ICD-10-PCS Official Guidelines for Coding and Reporting
⁵ NCCI Policy Manual for Medicare Services