Indications for the surgical treatment of osteomas of the frontal and ethmoid sinuses. Sixty-one patients with an osteoma of the frontal or ethmoid sinuses have been studied. The following indications for surgical removal of these osteomas are suggested: osteomas extending beyond the boundaries of the frontal sinus, if enlarging, if localized in the region adjacent to the nasofrontal duct, if signs of chronic sinusitis are present, osteomas of the ethmoid sinuses, irrespective of their size and if patients with osteomas complain of headache and other causes of headache have been excluded. The operation of choice is the osteoplastic flap operation. 