Otolaryngology Coding Alert

Question: A patient presents to the department for a functional endoscopic sinus surgery (FESS) procedure. The surgeon performs a bilateral anterior and posterior ethmoidectomy. The surgeon then performs a left frontal endoscopy including the removal of polypoid tissue. Additionally, a bilateral maxillary antrostomy is performed. The indicating diagnoses include recurrent acute ethmoid sinusitis and a frontal sinus polyp. What are the correct CPT® and ICD-10 codes?

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Answer: The correct ICD-10 codes are J01.21 (Acute recurrent ethmoid sinusitis) for the sinusitis and J33.8 (Other polyp of sinus) for the polyp.

Beware: In this example, there is no diagnosis supporting the bilateral maxillary antrostomy. Our response hinges on the assumption that there was, in fact, a medically necessary reason for performing the antrostomy. While the other two sinusitis codes can be linked with the maxillary sinustomy code, there is a chance that the payer will deny the procedure due to lack of medical necessity. It is recommended that you ask the surgeon to amend the operative note with an appropriate maxillary sinus diagnostic code.

In the case of a frontal sinus endoscopy, the surgeon generally performs an ethmoidectomy as a means of gaining access to the frontal sinus ostium. In this case, a complete ethmoidectomy is performed as expressed by the terms “anterior” and “posterior.” The correct code to apply for this procedure is 31255 (Nasal/sinus endoscopy, surgical; with ethmoidectomy, total [anterior and posterior]) with modifier 50 (Bilateral procedure).

Next, the physician documents frontal sinus endoscopic exploration with removal of polypoid tissue. The correct code for this procedure is 31276 (Nasal/sinus endoscopy, surgical with frontal sinus exploration, with or without removal of tissue from frontal sinus) with an LT (Left side) modifier, since the procedure is performed unilaterally.

Finally, the physician documents a bilateral maxillary antrostomy. Since there are no codes that include any of these three procedures together, the maxillary antrostomy codes separately as 31256 (Nasal/sinus endoscopy, surgical, with maxillary antrostomy) with modifier 50 appended.

A common mistake is to think that coding two sinus endoscopies together is incorrect. However, as long as the endoscopic work involves separate sinuses, you can code them together assuming you can provide medically necessary reasoning.