The Study Of Development And Variations Of Sphenoid Sinus By Helical Computed Tomography

Objective To investigate the age-related development and variations of human sphenoid sinus and its relationship with surrounding neurovascular structures, which willfacilitate to transsphenoid sinus operations.Methods Paranasal sinus was analyzed by helical computer tomographic scan incoronal and axial position and three-dimensional reconstruction in 148 cases of patients.The extent of aeration in the body of each patient was assessed on reformatted sagittal and coronal images. The measurements of the length of sphenoid sinus anterioposterior axis and horizontal transverse axis and height were obtained. The differences among groups of age, sex were analyzed; The correlations between the pneumatization of sphenoid sinus and protrusion of surrounding neurovascular structures protrusion was analyzed by SPSS 11.5 software.Results Sphenoid sinus pneumatization stars in the third year of life, the volume reaches mean level at 15 years old .Sphenoid sinus is 22.93±8.32 long, 33.09±l 1.83mm wide,19.75±6.12mm high on average. The volume of sphenoid sinus is 0-28ml. the mean volume is 7.97±3.12ml. There is a significant statistical relationship between different patterns and different age groups, but there is not a significant statistical relationship between different genders. There are 20 cases (13.51%,) undeveloped, 5 cases (3.38%) conceals, 16 cases (10.81%) presellar, 18 cases (12.16%) semisellar, 46 cases (31.08%) sellar, 27 cases (18.24%)sellaroccipital; lesser wing 18 cases (31.58%), greater wing 6 cases (10.53%), pterygoid process 8 cases (14.04%) and dorsum sellar5 cases (8.77%). The position and protrusion of vessels and nerves related to sphenoid sinus are different in various extent and shape of the pneumatization of it. There is a significant statistical relationship between the pneumatization of anterior clinoid process and little wing of sphenoid bone and the protrusion of the optic nerve into the sphenoid sinus ( x~2=60.640 P <0.001). A significant relationship between the clivus of occipital bone and the protrusion of the internal carotid artery 'is found (x~2=81.036, P <0.001). There is also a significant relationship between the pneumatization of pterygoid process and the pterygoid ( x 2=9.317,P=0.002).Conclusion There is a significant statistical relationship between different patterns and different age groups of sphenoid sinus, but there is not a significant statistical relationship between different genders. The volume and dimensions of sphenoid sinus can be estimated before transsphenoid sinus surgery by its pneumatization pattern. The variation of sphenoid sinus is obvious and the position and protrusion of surrounding neurovascularstructures is closely related to it.