Abstract
• Revision sinus surgery depends on knowing constant bony anatomical landmarks that are unaltered by prior surgery or advanced pathology.
• A wide maxillary antrostomy exposes the posterior lamellae and the medial orbital floor (MOF).
• The superior margin of the maxillary sinusotomy (junction of the inferior aspect of the lamina papyracea and MOF) forms a “bony ridge,” which delineates the anterior ethmoid cells (medially) from the orbital floor (laterally).
• The posterior margin of the maxillary sinusotomy (posterior fontanelle remnant), delineates the middle turbinate/sphenopalatine foramen (medially) from the posterior wall of the maxillary sinus (laterally).
• The relationship between the MOF and adjacent structures can help guide the surgeon.
• The posterior ethmoid cells lie superior to the posterior orbital floor adjacent and medial to the ridge of the antrostomy.
• The sphenoid sinus lies inferior to the MOF, adjacent to the nasal septum, approximately 7 cm from the columella.
• The nasolacrimal duct runs anterior, but parallel to the direction of the frontal recess and infundibulum.