Code Functional Endoscopic Sinus Surgery (FESS) With a Clear Head

FESS Coding

Consider anatomy and coding guidance to put things into perspective.

Functional endoscopic sinus surgery (FESS) is a surgical procedure performed endoscopically on the nasal/sinus cavities. The purpose of the surgery is to reduce the symptoms of chronic sinusitis such as congestion, drainage, post-nasal drip, headaches, and facial pain. FESS Coding  can be unnerving because there are multiple codes associated with the surgery. Reviewing sinus anatomy and coding guidance for FESS Coding  will help you keep a clear head when coding these claims.

Sinus Anatomy

There are four separate sinus cavities (jointly, the paranasal sinuses) on each side of the face. They are:

  • Maxillary (antrum). These air-filled sinuses are located below the eye, behind the cheek.
  • Ethmoid. The ethmoid sinuses are between the eye and the nasal cavity. The concha bullosa is an extension of the ethmoid sinus located in the middle turbinate.
  • Sphenoid. The sphenoid is a wedge-shaped bone in the middle of the skull that contains the sphenoid sinuses. It is located between the back of the nasal space and the cranial cavity. Just lateral or beside the sphenoid sinus are the optic nerves and the intracranial portion of the carotid arteries.
  • Frontal. These sinus cavities are located above the eye in the forehead region.

Diagnoses That May Require FESS Coding

The most common indications for endoscopic nasal/sinus surgery are rhinosinusitis (sinusitis), polyp, cyst, neoplasm, and polypoid sinus degeneration. Common diagnoses and associated ICD-10-CM codes include:

  • Chronic pansinusitis (J32.4) — when all four sinus cavities have chronic sinusitis. If coded individually: maxillary (J32.0), frontal (J32.1), ethmoid (J32.2), and sphenoid (J32.3).
  • Other chronic sinusitis (J32.8) — when more than one sinus cavity has chronic sinusitis.
  • Acute, recurrent pansinusitis (J01.41) — when all four sinus cavities have acute, recurrent sinusitis. (Per ICD-10-CM, as it relates to sinusitis, the term “recurrent” is associated with acute, not chronic.)
  • Other acute, recurrent sinusitis (J01.81)
  • Polyps (J33.8)
  • Cyst and mucocele of nose and nasal sinus (J34.1)
  • Polypoid sinus degeneration (J33.1)
  • Other specified disorders of nose and nasal sinuses (J34.89)

Coding FESS Procedures

During surgery, the surgeon will perform diagnostics on the internal anatomy of the nasal/sinus cavities with the assistance of an endoscope for increased visualization and magnification. The surgeon inspects the interior nasal cavity, the middle and superior meatuses, the turbinates, and the sphenoethmoid recess. This diagnostic portion of the surgery is reported using the appropriate code from CPT® code range 31231-31235.

According to the CPT® code book, diagnostic endoscopy and sinusotomy (the incising of a sinus) are included in the surgical sinus endoscopy codes 31237-31298. Diagnostic codes 31231-31235 are not reported separately with surgical codes 31237-31298. Additionally, according to the CPT® code book, “To report these services when all of the elements are not fully examined (eg, judged not clinically pertinent), or because the clinical situation precludes such exam (eg, technically unable, altered anatomy), append modifier 52 if repeat examination is not planned, or modifier 53 if repeat examination is planned.”

Procedure codes 31233-31294 are unilateral. When performed on both the right and left sinus cavity, append modifier 50 Bilateral procedure to the procedure code. CPT® code 31231 is listed as unilateral or bilateral, making it inappropriate to append modifier 50 to this code.

FESS Coding Guidance

To select the correct code, read the body of the operative report to ensure that documentation supports the procedure listed under the Procedures heading. Specific terminology or a sufficient description of the procedure must be documented. Here are examples of the work involved in specific procedure codes:

Endoscopic Maxillary Antrostomy — Vignette for Code 31256 (CPT® Assistant, January 1997)

The maxillary sinus ostium is palpated and visually identified. Residual inferior bony uncinate remnants are removed, and the ostium enlarged posteriorly, inferiorly, and anteriorly as indicated. Bony partitions, as between the natural maxillary sinus ostium and a Haller cell above, may require removal to relieve the obstruction. Hemostasis with topical agents or sponge insertion may be required.

If the description in the body of the operative report does not indicate that the ostium was violated, it may not be appropriate to code the procedure. Best practice is to query the provider when in doubt.

Endoscopic Maxillary Antrostomy with Tissue Removal for Code 31267 (Coders’ Desk Reference for Procedures 2019)

Code 31267 has all the elements of 31256. In 31267, the maxillary sinus may be opened, and the mucosa removed.

Endoscopic Total Ethmoidectomy — Vignette for Code 31255 (CPT® Assistant, January 1997)

The surgery begins with complete uncinate process removal. The anterior ethmoid cells are removed, and the medial orbital wall identified and skeletonized under endoscopic visualization. The middle turbinate ground lamella is penetrated and removed, and the posterior ethmoid cells are removed back to the anterior sphenoid wall, which is followed up to the skull base. The skull base is then skeletonized and followed forward to the frontal recess at the anterior ethmoid artery.

Endoscopic Frontal Sinus Exploration for Code 31276 (Coders’ Desk Reference for Procedures 2019)

A sinusotomy of the frontal sinus ostium is performed. If diseased or abnormal tissue is present within the frontal sinus, a scalpel or biting forceps is introduced parallel to the endoscope and is used to remove the tissue. This procedure includes polypectomy, debridement, or biopsy of the frontal sinus tissue when performed. Electrocautery may be used for hemostasis. The nasal cavity may be packed with Telfa or gauze.

There does not have to be tissue removed from the frontal sinus cavity to code for this procedure. The surgeon may explore the cavity. Also, the Coders’ Desk Reference for Procedures states, “If diseased or abnormal tissue is present ….” This implies there may not be diseased or abnormal tissue within the frontal sinuses.

Endoscopic Sphenoid Sinus for Code 31287-31288 (Coders’ Desk Reference for Procedures 2019)

The sphenoid can be explored with direct access or through the posterior ethmoid sinus. The isolated access to the sphenoid sinus is through dilation of the sphenoid ostium. The middle turbinate may be fractured or partially removed for access. The ostium is cannulated and dilated. The physician uses forceps or a sphenoid punch to open the sinus cavity. Additionally, diseased mucosa or tissue is removed in 31288.

Combination codes 31253, 31257, 31259 (Total Ethmoidectomy with Frontal Sinus Exploration or Total Ethmoidectomy with a Sphenoid Sinusotomy, or with a Sphenoidotomy and Removal of Tissue) – CPT® Assistant, April 2018

Code 31253 includes the work of codes 31255 and 31276. Code 31253 is reported when a complete/total ethmoidectomy is performed with frontal sinus exploration. If only a partial ethmoidectomy is performed in conjunction with a frontal sinus exploration, report codes 31254 and 31276.

Code 31257 includes the work of both codes 31255 and 31287. Code 31257 is reported when a complete/total ethmoidectomy is performed with a sphenoidotomy (sphenoid sinusotomy). If only a partial ethmoidectomy is performed in conjunction with a sphenoidotomy, report codes 31254 and 31287.

Code 31259 includes the work of codes 31255 and 31288. Code 31259 is reported when a complete/total ethmoidectomy is performed with a sphenoidotomy and removal of tissue from the sphenoid sinus. If only a partial ethmoidectomy is performed in conjunction with a sphenoidotomy and removal of tissue from the sphenoid sinus, report codes 31254 and 31288.

There are four separate sinus cavities on each side of the face.

Coding Separate Procedures

Within the endoscopic sinus surgery codes, there are two separate procedure designated codes: 31231 Nasal endoscopy, diagnostic, unilateral or bilateral (separate procedure) and 31237 Nasal/sinus endoscopy, surgical; with biopsy, polypectomy or debridement (separate procedure).

According to National Correct Coding Initiative (NCCI): “A procedure designated by the CPT code descriptor as a ‘separate procedure’ is not separately reportable if performed in a region anatomically related to the other procedure(s) through the same skin incision, orifice, or surgical approach.”

In other words, when performed on the same side (ipsilateral), it would be incorrect to bill 31231 or 31237 with the endoscopic surgical codes (31238-31294). However, because there are two orifices (right and left nasal cavities), when performing a diagnostic procedure on the right side and a surgical procedure on the left side, both procedures may be reported. Modifier 59 Distinct procedural service may be required with 31231 and 31237.

Coding the Stereotactic Computer-Assisted Navigation System

According to CPT® code book, the Brainlab navigation system may be used to facilitate the performance of endoscopic sinus surgery, and is reported with 61782 Stereotactic computer-assisted (navigational) procedure; cranial, extradural (List separately in addition to code for primary procedure) when the procedure is performed in conjunction with endoscopic sinus surgery.

One explanation for use of this system is that the paranasal sinuses share a common thin wall with the eye socket (or orbit) and cranial cavity. When performing surgery in a highly delicate region, the surgeon relies on the system to navigate the area through the identification of anatomical landmarks. The ethmoid, for example, is a facial bone located between the eyes whose upper portion lies just below the cranial cavity. According to the Cleveland Clinic, “All operations on the ethmoid sinus carry a rare chance of creating a leak of cerebral sinus fluid (CSF).” The risk of CSF leak is potentially reduced because the endoscope allows for improved visualization. Nevertheless, a CSF leak could lead to an infection, potentially resulting in meningitis.

When coding the navigation system, the surgeon’s documentation should describe the setup. Examples include:

  • “The surgical navigation system was set up and found to be accurate after registration.”
  • “The registration sticker for the Medtronic image guidance system was placed on the forehead. The face was registered with good correlation. Landmarks were checked with the probe, which showed satisfactory accuracy.”
  • “Image guidance was placed on the patient and calibrated.”

The surgeon’s documentation should also describe the area in which the system was used. For example:

  • “Surgical navigation was used to confirm the position of the lamina papyracea (i.e., medial orbital wall), skull base, and frontal recess cells.”

When an otolaryngology surgeon performs the approach of a procedure, and a neurosurgeon performs the resection on that same patient for a cranial mass or tumor, both surgeons may require the use of the navigation system. However, only one MUE is allowed per day for the navigation system, and the CPT® code does not allow for co-surgery (modifier 62). The CPT® code does, however, allow for an assistant surgeon (modifier 82) (see the Medicare Physician Fee Schedule); therefore, if the documentation supports its use, the neurosurgeon may bill for the navigation system appending modifier 82 to the CPT® code.

Additionally, when a neurosurgeon is involved, the CPT® code may be 61781 Stereotactic computer-assisted (navigational) procedure; cranial, intradural (List separately in addition to code for primary procedure) for an intradural cranial procedure, rather than 61782 (extradural). Why 61781 instead of 61782? If a neurosurgeon is involved, the surgical target may be intradural. Therefore, regardless of whether the otolaryngology surgeon’s work is performed extradural (outside the dura), the code is driven by the location of the surgical target.

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