Frontal sinus cranialization is an established procedure utilized in instances wherein the posterior table has been irreversibly compromised. A known complication of this procedure is pneumocephalus, which may develop if the frontal recess has not been fully separated from the cranialized sinus. We report 3 cases wherein massive pneumocephalus developed after cranialization of the frontal sinus. In each case, a novel endoscopic repair was undertaken utilizing a middle turbinate hinge flap to obliterate the frontal recess. In each instance, obliteration of the frontal recess resulted in durable resolution of pneumocephalus.