Please remember that the endoscopic sinus surgery codes have zero global, 31276, 31255, 31254, 31267, 31256, 31288, 31287; so, nasal endoscopy (31231) done post-operatively would be billable......if your surgeon performed any other procedures in conjunction with the sinus surgery, such as, septoplasty (30520) and/or turbinectomies (30130, 30140), then you add a 90 global to the surgery; if your surgeon does a nasal endoscopy post-operatively with that scenario, then you need know if the scope was done to check the healing of sinuses or done to remove splints from the septoplasty, etc... It's a gray area and one you need to have good documentation on, the scope is still billable in this scenario using modifier 79 if applicable.
Jennifer
CT ENT