A method is provided for accessing and treating at least one of a maxillary sinusitis, sphenoid sinusitis and frontal sinusitis. A perforation is created in an uncinate via an anterior keyhole. A position of an MSO is verified using a probe. The probe is used to verify dimensions of the MSO. A verification is made that an anteroposterior length of the ostium is sufficient. A targeted medial displacement of a medial wall of the maxillary sinus and uncinate is made using an uncinate medializing device.
