Dimensions of the medial wall of the prelacrimal recess

Background: Addressing anterior maxillary sinus pathology endoscopically that is inaccessible with an endoscopic modified medial maxillectomy requires either a prelacrimal approach (PLA) or an endoscopic Denker's approach (EDA). The PLA involves removing the medial wall of the prelacrimal recess (PLR), which is the bone between the pyriform aperture (PA) and nasolacrimal duct (NLD), from nasal floor to orbital floor. The PLA preserves the inferior turbinate and NLD, whereas both are sacrificed during an EDA. The purpose of this computed tomography (CT)-based study was to determine the anteroposterior and superoinferior dimensions of the medial wall of the PLR. Methods: One hundred thirty-one triplanar sinus CT scans of patients with various rhinologic diseases, but with intact bony PLR walls, were reviewed to assess dimensions of the medial wall of the PLR. The anteroposterior distances from the PA to the inferior-most, middle, and superior-most aspects of the NLD were measured. The height from the nasal floor to orbital floor was also measured. Combining left and right sides, there were 262 measurements. Results: The anteroposterior distances between the PA and the NLD were as follows: inferior: mean, 8.4 mm (standard error [SE], 0.2; range, 1.9-14.2); middle: mean, 7.6 mm (SE, 0.2; range, 0-13.6); and superior: mean, 5.5 mm (SE, 2.5; range, 0-11.9). The mean height of the medial wall of the PLR was 26.5 mm (SE, 0.2; range, 18.5-39.9). Conclusion: The anteroposterior and superoinferior dimensions of the medial wall of the PLR are variable, with the anteroposterior dimension being widest inferiorly. Its dimensions should be evaluated preoperatively when considering endoscopic approaches to or through the anterior maxillary sinus. (C) 2018 ARS-AAOA, LLC.