Patient presented to the OP Surgery Department for a FESS under general anesthesia. Procedures included: Left frontal sinus endoscopy including exploration and removal of diseased tissue; Bilateral anterior & posterior ethmoidectomy; and, Bilateral maxillary antrostomy. Pathologic diagnosis: Chronic sinusitis involving the ethmoid sinus.

I billed 31255,31276,31265-50 but I got a denial stating missing a modifier