Approach to frontal sinus via five frontal sinus drainage pathways.

Abstract

Purpose: This study aimed to validate a method for successful frontal sinus surgery. The method classifies the frontal sinus drainage pathway (FSDP) into five categories based on three bony walls of the anterior ethmoid sinus, including the uncinate process (UP), accessory uncinate process (UPa), and basal lamella of the ethmoid bulla (BLEB), which was tested in actual surgical procedures.

Methods: This study analyzed 53 sides of 48 patients who underwent frontal sinus surgery between October 2022 and March 2023. We classified the FSDPs using preoperative computed tomography (CT) and multiplanar reconstruction (MPR). During surgeries for FSDPs located anterior to the BLEB, we used a two-step method involving resection of the turbinal UP, followed by upward resection from the lower edge of the ethmoidal UP. For FSDPs located posterior to the BLEB, we resected the BLEB at the superior semilunar recess.

Results: We confirmed the origin of each of the five types of FSDP during surgery. These origins, which were located at the lowest part of the anterior ethmoid, could be identified in the early stages of ethmoid sinus surgery before proceeding to the frontal recess area.

Conclusion: The origins of the five types of FSDP, classified based on the bony walls, can be clearly and accurately identified during surgery. This provides a reliable method for preoperatively predicting and locating the inferior end of the FSDP (origin), without extensive manipulation of the cells formed in the frontal fossa.