Surgical techniques
All patients underwent ESS under general anesthesia and video recorded by either a blinded
rhinologist staff or a fellowship-trained rhinologist supervised by rhinologist staff. The sinuses were sequentially opened into the common cavity fashion: uncinectomy and middle meatal antrostomy, anterior and posterior ethmoidectomy, sphenoidotomy and frontal sinusotomy (Draf IIa). The blue-light filter system with 0, 45, and 70-degree nasal endoscopes (Karl Storz, Tuttlingen, Germany) were applied during video record at each interesting anatomical area, including the OMU, maxillary sinus, anterior and posterior ethmoid air cells, sphenoid sinus and frontal sinus, respectively aiming to examine the degree of fluorescein stain. The normal saline irrigation and the application of cotton pledget were not allowed to be used during the procedure. Patients with significant intraoperative bleeding must be excluded from the data analysis due to fluorescein obscuring.