Anterior maxillary wall and lacrimal duct relationship - CT analysis for prelacrimal access to the maxillary sinus

The distance between the anterior wall of the maxillary sinus and the nasolacrimal duct shows a large individual variation.

To evaluate the feasibility of accessing the maxillary sinus through a prelacrimal window access (PLWA), a series of 100 paranasal CT scans from adult patients was analysed retrospectively. The distance between the anterior maxillary wall and the anterior border of the lacrimal duct (= prelacrimal window) were measured in 200 sides.

A distance of more the 7 mm was found in 12.5% maxillary sinuses and would enable straight forward PLWA. A distance between smaller than 7mm and larger than 3mm was present in 56.5% of sinuses, and would make surgical access more demanding. In 31.5% of maxillary sinuses the distance was smaller than or equal to 3mm and in these patients this approach would be difficult without transecting the nasolacrimal duct.

Only in 12.5% of sinuses a prelacrimal endoscopic access is readily feasible, while in 56.5% temporary tear sac dislocation is required and in 31.5% lacrimal sac dislocation is always needed along with a significant amount of bone removal to enable PLWA.