Computed tomography in the evaluation of postoperative maxillary cysts.

Twenty-two cases (34 sides) of postoperative maxillary cysts evaluated with axial and coronal computed tomograms were reviewed. Precise characteristics pertaining to the extent of maxillary sinus involvement, loculation, presence of septae, bony perforation, and associated cystic projection or extension into adjacent structures were determined. Of the 34 sides, 13 cysts involved the sinus completely. Twelve were multilocular. Thirteen exhibited incomplete septae. Perforations were most frequent in the anterolateral and medial bony walls (28 and 27, respectively); however, the 14 posterolateral wall perforations showed a higher percentage of cystic projection into adjacent structures. Ethmoid extension was seen on two sides, orbital extension on one. Nine sides showed tooth roots communicating with the cyst. The routine use of computed tomography in the evaluation of this type of cyst is proposed.