Onodi cellの同定と内視鏡下鼻副鼻腔手術のための新しい蝶形骨洞の分類法

Abstract

There is no effective classification method for the opening of the sphenoid sinus. The objective of this study was to examine the effectiveness of identification of the Onodi cell and classification of the sphenoid sinus using sagittal computed tomography (CT) for sphenoidotomy. CT images of the sinuses of surgical patients (n=261, 522 sides) were studied. Using sagittal CT images, the relationships between the lateral side of the anterior wall of the sphenoid sinus and the optic nerve, and between the middle of the anterior wall of the sphenoid sinus and the skull base or pituitary gland were studied. Images were classified as the Skull base- (without the Onodi cell), Optic canal-, Sella-, or Infra-Sella- (all with the Onodi cell) type. Two hundred fifty-seven sides (49.2%) were of the Skull base-type, 181 (34.7%) were of the Optic canal-type, 58 (11.1%) were of the Sella-type, and 26 (5.0%) were of the Infra-Sella-type; i.e., the Onodi cell was present in 50.8% of the sides. The width of the anterior wall of the sphenoid sinus became narrower as it shifted from the Skull base-type to the Infra-Sella-type. Classification of the anterior wall of the sphenoid sinus based on the Onodi cell allows three-dimensional assessment of the shape of the sphenoid sinus. We believe that the sphenoid sinus can be opened safely by full preoperative assessment of the anterior wall type, position of the superior turbinate and ostium of the sphenoid sinus, respectively.