Documentation of variations in sinonasal anatomy by intraoperative nasal endoscopy

Functional endoscopic sinus surgery (FESS) requires a thorough understanding of the variability in sinonasal anatomy. Previous reports have relied primarily on anatomic studies of cadaveric specimens or skulls, or on radiographic analysis. Relatively few comparative anatomic data have been accumulated with endoscopic examination of living patients.

Retrospective review of video recordings of 119 consecutive patients undergoing intraoperative nasal endoscopy at the time of sinonasal surgery.

At the beginning of each surgical procedure, endoscopic examination of the nasal cavities was performed with 0 degrees and 30 degrees telescopes and recorded with a three-chip video camera on 3/4-inch U-matic videotape. These video records were then reviewed with attention to variations in anatomical configuration of different sinonasal structures.

Data demonstrating variations in the anatomical configuration of the following structures of the lateral nasal wall are presented. Middle turbinate: typical (63%), concha bullosa (15%), sagittal cleft (6%), laterally displaced (4%), "L" shaped (3%), medially bent (3%), laterally bent (3%), medially displaced (2%), and transverse cleft (0.5%). Uncinate process: typical (85%) and medially rotated (15%). Ethmoid bulla: typical or balloon (45%), sausage-shaped (34%), and flat (21%). Accessory ostium: round (50%), oval (46%), and kidney-shaped (4%). Sphenoid sinus ostium: oval (42%), slit (32%), and round (26%). The classification system for the anatomical categories is illustrated with digitized images.

This study attempts to provide statistical data regarding variations in sinonasal anatomy in living subjects. Familiarity with such anatomy is important in differentiating normal variants from pathological conditions to optimize surgical treatment of sinus disease, while avoiding complications.