Figure 6: Frontal sinus drainage type I according to Draf = complete resection of the uncinate process and resection of parts of the medial lamella of the agger nasi cell and the anterior wall of the ethmoid bulla if needed [242, 246, 248, 359]. A different postoperative situation results depending on the individual anatomy: on the right isolated agger nasi cell, on the left side additional posterior frontoethmoidal cell (frontal bulla), intersinus septal cell; 1 = agger nasi cell, 2 = posterior frontoethmoidal cell (frontal bulla), 3 = interfrontal sinus septal cell, 4 = ethmoid bulla; a) coronal CT scan, b) axial CT scan, c) sagittal CT scan.