Question: Should we append modifier -50 (Bilateral procedure) to 31237 (Nasal/sinus endoscopy, surgical; with biopsy, polypectomy or debridement [separate procedure])? Florida Subscriber Answer: Yes. With the exception of 31231 (Nasal endoscopy, diagnostic, unilateral or bilateral [separate procedure]), functional endoscopic sinus surgeries (FESS) are unilateral procedures that may be appended with modifier -50 if the surgery is performed on both sides of the nose. Depending on the carrier, the bilateral procedure is reported on either one line or two. Most private carriers prefer two lines: The majority of Medicare carriers, meanwhile, require a one-line submission: Note: Some carriers require modifiers -LT (Left side) and -RT (Right side) instead of modifier -50. You Be the Coder and Reader Questions answered by Randa Blackwell, financial specialist with the otolaryngology division of the department of surgery at the University of Maryland in Baltimore; Barbara Cobuzzi, MBA, CPC, CPC-H, an otolaryngology coding and reimbursement specialist and president of Cash Flow Solutions, a medical billing firm in Lakewood, N.J.; Lee Eisenberg, MD, an otolaryngologist in private practice in Englewood, N.J.; Tara Kaye, appeals coordinator with Atlanta ENT, a large otolaryngology practice with offices throughout metropolitan Atlanta; Melissa Pointer, CPC, billing manager with the otolaryngology division at the University of Arkansas for Medical Sciences in Little Rock; and Teresa Thompson, CPC, an otolaryngology coding and reimbursement specialist in Sequim, Wash.