OBJECTIVE: The objective of this study was to investigate the radiologic and endoscopic anatomy of the anterior ethmoidal canal (AEC) and feasibility of endoscopic ligation of the anterior ethmoidal artery (AEA). STUDY DESIGN: The authors conducted a prospective analysis of computed tomography (CT) of the paranasal sinuses and endoscopic cadaver dissection. METHODS: Twenty-two cadaver heads had CT scans of the paranasal sinuses. The height of the lateral lamella of the cribriform plate was calculated and staged according to the Keros staging system. The presence of a bony mesentery, distance from AEC to the skull base, and dehiscence of the AEC were documented. Forty-four dissections were performed, the AECs identified, and AEA ligation attempted. RESULTS: The mean height of the lateral lamella was 5.4 mm on the right and 4.7 mm on the left. In all cadaver heads with asymmetry, the right lateral lamella was longer (P<.005). A Keros type 1 pattern was seen in 23%, type 2 in 50%, and type 3 in 27%. Thirty-six percent of AECs were in a bony mesentery. AEC distance from the skull base was greater on the right (P<.009). A longer lateral lamella was correlated with the artery being in a mesentery. Sixteen percent of the AECs were dehiscent. Sixty-six percent of AEAs were unable to be clipped. Twenty percent were clipped effectively, all in a mesentery. In 14%, the AEA was not effectively clipped. CONCLUSIONS: Endoscopic AEA ligation may be possible in some patients. The AEA should be in a mesentery for an effective clip to be placed and be associated with a dehiscence of the AEC. If the lateral lamella is classified as Keros grade 2 or 3, it is likely the AEC will be found in a mesentery.
OBJECTIVE: The objective of this study was to investigate the radiologic and endoscopic anatomy of the anterior ethmoidal canal (AEC) and feasibility of endoscopic ligation of the anterior ethmoidal artery (AEA). STUDY DESIGN: The authors conducted a prospective analysis of computed tomography (CT) of the paranasal sinuses and endoscopic cadaver dissection. METHODS: Twenty-two cadaver heads had CT scans of the paranasal sinuses. The height of the lateral lamella of the cribriform plate was calculated and staged according to the Keros staging system. The presence of a bony mesentery, distance from AEC to the skull base, and dehiscence of the AEC were documented. Forty-four dissections were performed, the AECs identified, and AEA ligation attempted. RESULTS: The mean height of the lateral lamella was 5.4 mm on the right and 4.7 mm on the left. In all cadaver heads with asymmetry, the right lateral lamella was longer (P<.005). A Keros type 1 pattern was seen in 23%, type 2 in 50%, and type 3 in 27%. Thirty-six percent of AECs were in a bony mesentery. AEC distance from the skull base was greater on the right (P<.009). A longer lateral lamella was correlated with the artery being in a mesentery. Sixteen percent of the AECs were dehiscent. Sixty-six percent of AEAs were unable to be clipped. Twenty percent were clipped effectively, all in a mesentery. In 14%, the AEA was not effectively clipped. CONCLUSIONS: Endoscopic AEA ligation may be possible in some patients. The AEA should be in a mesentery for an effective clip to be placed and be associated with a dehiscence of the AEC. If the lateral lamella is classified as Keros grade 2 or 3, it is likely the AEC will be found in a mesentery.