We have a patient that the doctor did a myringotomy and also a nasal endoscopy. She did the endoscopy to check to see if there were any nasal masses because the patient had a long history of right adhesive middle ear disease and history of right mastoid effusion. The diagnosis codes used were 381.3 and 389.00. Would the diagnoses prevent us from billing for the nasal endoscopy? And if billed for both, would we used modifier 51 or 59 on the nasal endoscopy?