Evaluating the safety of frontal sinus trephination

Objectives/Hypothesis: The depth of the frontal sinus was measured using axial computed tomography (CT) images to examine the safety of frontal sinus trephination at selected distances from the midline. Study Design: Review of 200 sinus CT scans. Methods: Two hundred sinus CT scans (400 frontal sinuses) were reviewed to measure the frontal sinus depth at 5 mm, 10 mm, and 15 mm from midline. Results: Males had a significantly deeper frontal sinus than females at all measurements points (P < .001). The measurements revealed a considerable number of small but nonhypoplastic frontal sinuses, which were shallower than the length of standard frontal trephine instruments (7 mm) and would risk penetration of the posterior table of the sinus. Of all frontal sinuses studied, 9.54% were