Anatomical variation of the pneumatized superior turbinate and its impact on endoscopic sinus surgery in chronic rhinosinusitis.

PURPOSE

The posterior ethmoid sinus is adjacent to important structures, such as the orbit, optic nerve, skull base, and ostium of the sphenoid sinus. The purpose of this study was to examine the effect of pneumatization of the superior turbinate (ST) and its basal lamella, and of the position of the anterior wall of the sphenoid sinus, on opening of the posterior ethmoid and sphenoid sinuses.

METHODS

On axial, coronal, and sagittal computed tomography images, 394 sinuses of 197 patients who underwent endoscopic sinus surgery at Toho University Omori Medical Center in Tokyo, Japan, were classified according to the presence or absence of pneumatization of the ST and its basal lamella. The basal lamella of the ST was classified separately into the vertical and horizontal portions. We examined whether the classification of the anterior wall of the sphenoid sinus was associated with the structure of the ST.

RESULTS

Pneumatization was observed in the ST in 28 sinuses (7.1%), in the vertical portion of the basal lamella in 127 (32.2%), and in the horizontal portion of the basal lamella in 90 (22.8%). Pneumatization in the horizontal portion of the basal lamella was significantly more common in the anterior sphenoidal wall classified as optic-canal type.

CONCLUSION

Consideration should be given to the pneumatization of the ST and its basal lamella and optic-canal-type anterior sphenoidal wall, because these reduce the volume of the posterior-most ethmoid cell and may increase the risk of damaging the skull base and optic nerve.