[Anatomy and imaging study of a new upper-agger nasi pathway of frontal sinus surgery]

To investigate the new surgical pathway of endoscopic frontal sinus surgery for frontal sinus lesions through the upper-agger nasi approach.

The computed tomography (CT) scans from 32 patients were collected and subjected to three-dimensional reconstruction by Mimics. The distance in sagittal planes from anterior ethmoid artery to midpoint of axilla and to skull base attachment at anterior middle turbinate was measured. The distance in coronal planes between the perpendicular plate of middle turbinate and the orbital lamina was also detected as well as the height of agger nasi. Three-dimensional structures of the frontal sinus and its surrounding cells was reconstructed by Sinuses Trachea I software. We integrated the CT scans and the above data for simulating surgical operation on cadaveric heads.

(1) Skull base attachment at anterior middle turbinate located at the anterior or posterior of aperture of frontal sinus. (2) The mean distance between anterior ethmoid artery and midpoint of axilla was (22.23 ± 2.78) mm on the left side and (22.30 ± 2.80) mm on right. The mean distance between anterior ethmoid artery and skull base attachment at anterior middle turbinate was (15.31 ± 2.82) mm on left and (15.39 ± 3.53) mm on right. The distance between perpendicular plate of middle turbinate and orbital lamina was (7.61 ± 1.34) mm on left and (7.80 ± 1.40) mm on right side. The height of the agger nasi was (8.33 ± 2.14) mm on left and (8.00 ± 2.57) mm on right. There was no statistical difference in the above data between left and right side (P > 0.05). (3) The visible three-dimensional structure showed that skull base attachment at the anterior middle turbinate was closely adjoined the aperture of frontal sinus, the space between sub-outer side of the attachment and orbital lamina, above the agger nasi cell or the upper area of the agger nasi cell was solely cell structures.

Endoscopic frontal sinus surgery for frontal sinus lesions through the upper-agger nasi approach was practicable to solitary frontal sinus lesions and to solve the complex frontal sinus or frontal recess lesions by flexible operation according to the feature of the lesions.