Minimally invasive medial maxillectomy and the position of nasolacrimal duct: the CT study.

Several minimally invasive modifications of endoscopic medial maxillectomy have been proposed recently, with the least traumatic techniques utilizing the lacrimal recess as a route to enter the sinus. The aim of the study was to analyze the anatomy of medial maxillary wall in the region of nasolacrimal canal and, thus, to determine the capability of performing minimally invasive approach to the maxillary sinus leading through the lacrimal recess. The course of nasolacrimal canal and the distance between the anterior maxillary wall and the nasolacrimal canal (the width of lacrimal recess) were evaluated in 125 randomly selected computed tomography (CT) head examinations. The proportion of cases with unfavorable anatomical conditions (lacrimal recess too narrow to accept a 4 mm optic) to perform minimally invasive middle maxillectomy was assessed. The width of lacrimal recess, measured at the level of the inferior turbinate attachment, varied between 0 and 15.2 mm and was related to slanted course of nasolacrimal canal. The more perpendicular the axis of the canal to the nasal flor, the narrower the lacrimal recess. In about 16% of cases, lacrimal recess width was less than 4 mm and in 14.4% it was missing. The endoscopic approach to maxillary sinus leading through lacrimal recess is possible in about 70% of patients. In the remaining group of patients when the lacrimal recess is too narrow, this type of approach may be difficult to perform without damaging the piriform aperture rim or bony framework of nasolacrimal duct, or it may be impracticable when lacrimal recess is missing.