During a four-hour interview at his home, Mattis--a restless, intense livewire of a man--doesn't sit down even once (nor does he offer his visitor a chair).
They ended up producing a flexible catheter tube that goes a bit of the way up the nostrils, then a guide wire is inserted into the targeted sinus. (In live patients this is done via an endoscope and fluoroscope.) A balloon catheter is advanced over the guide wire and positioned against the blocked ostium.