Computer-assisted Imaging Anatomical Study Of The Nasofrontal Region

Objective:(1) Discuss the value of Advantage Windows 3.1 (AW 3.1) imaging software for anatomical study of nasofrontal region.(2) Investigate the imaging characteristics of nasofrontal regionwhich related to the frontal sinus surgery.Methods:80 adults [ 50 patients (100 sides) with chronic sinusitis and 30 healthy adults (60 sides) ] underwent axial consecutive computed tomography scans and then were studied with AW 3.1 imaging software that provides reconstructional imaging of continuous coronal, sagittal, axial sections. Some structures of nasofrontal region were studied and measured.Results:AW 3.1 imaging sofeware can identify and measure the following structures accurately. (1) The diameter of frontal sinus: (22.5 ?8.6) mm in height, (16.3 ?6.8) mm in depth, (23.8 ?9.8 )mm in breadth. (2) The diameter of frontal sinus ostium: the anterior-posterior diameter was (7.3 ?1.7) mm, the transverse diameter was (8.5 ?1 .9 ) mm. (3) The width of nasal beak of frontal (5.9 ?.4) mm. (4) The frontal sinus ostium and anterior ethmoid artery distance to the floor of columella nasi and the corresponding angle to the nasal floor(60.8 mm ?4.2 mm , 64.3 mm ?4.6 mm, 70.1??4.7? 57.6??4.5?. (5) The uppermost attachment sites of the uncinate process (lamina papyracea 41%, posteromedial wall of agger nasi cell 11%, middle turbinate 19%, anterior skull base 16%, superior bifurcation 13%). (6) The cells can impinge on the frontal recess to cause obstruction (terminal cells 38.8%, anterior ethmoid cells 27.6%, agger nasi cells 24.5%). (7) The accessory cells can impinge on the frontal sinus (perifrontal cells 32.7%, superaorbital cells 38.8%, intersinus septal cells 32%). (8)There is significant difference of characteristics of some air cells development surrounding the nasofrontal region between patients with frontal sinusitis and healthy adults. Conclusions:(1) AW 3.1 imaging software is a helpful and powerful new tool for anatomical study of nasofrontal region and for preoperative(2004)evaluation. These results of anatomical study of nasofrontal region are helpful in directing the functional endoscopic surgery of frontal sinus.(2) The natural ostium of frontal sinus in most patients with frontal sinusitis is big enough to support normal draining. It is needless to enlarge the natural ostium of frontal sinus, but to remove the cells surrounding the natural ostium of frontal sinus which narrow the outflow tract of itself.(3) The structures of nasofrontal region are complex and various.Frontal sinusitis may result from the obstruction and narrowing of frontal sinus outflow tract, which caused by some excessive aerification cells surrounding the nasofrontal region ( for example terminal cells, anterior ethmoid cells, agger nasi cells, perifrontal cells ).