| Objective: The endonasal transsphenoidal approach to the sellar region was simulated on the head of adult cadavers,and the related structures involved in the surgical approach were microdissected,so as to grasp the anatomical characteristics of the nasal cavity,sphenoid sinus and sellar region.The purpose of this study was to provide anatomical basis for the clinical treatment of pituitary adenoma and other sellar region lesions by endonasal transsphenoidal approach.Methods: In this study,5 dry skull specimens were used to observe and familiarize themselves with the related bony structures and their anatomical relationships.Frozen fresh Chinese wet cadaver heads were used in 6 cases(12 sides).After vascular perfusion and embalming,one specimen was cut along the median sagittal plane and dissected layer by layer from medial to lateral under the microscope,and the other 5 cases simulated the endonasal transsphenoidal approach to the sellar region.The related structures involved in the surgical path were dissected,and the relevant data were analyzed and sorted out after accurate measurement.Results: 1.The distance between the anterior edge of the sphenopalatine foramen and the anterior nasal spine was 54.2 ±2.9 mm(48.6-57.8 mm),the angle between the anterior edge of the sphenopalatine foramen and the bottom of the nasal cavity was 27.1 ±1.8°(24.5-30.2°).The distance between the superior edge of sphenopalatine foramen and the lower end of sphenoid sinus ostium was 10.3 ±1.8 mm(7.2-13.1 mm).The distance from the superior branch of the posterior nasal septal artery to the lower end of the sphenoid sinus ostium was 4.1 ±1.0 mm(2.9-6.1 mm),and the distance from the inferior branch of the posterior nasal septal artery to the lower end of the sphenoid sinus ostium was 7.9±1.9 mm(5.4-10.6 mm).2.The sphenoid sinus ostium was located in the sphenoethmoidal recess above the superior turbinate.The bilateral sphenoid ostiums were "eight" shaped on the anterior wall of the sphenoid crest,the upper edge was close to the midline,and the lower edge was far away from the midline.The ostium of the bony sphenoid sinus was oval in 10cases(83.3%),round in 2 cases(16.7%),the longitudinal diameter of the sphenoid ostium was 5.8 ±1.2 mm(3.8-7.5 mm),the transverse diameter of the sphenoid ostium was 3.7 ±0.7 mm(2.2-4.6 mm).The distance between the upper end of the sphenoid ostium and the midline was 2.9 ±1.0 mm(1.0-4.0 mm),and the lower end of the sphenoid ostium was 5.0 ±1.0 mm(3.7-6.7 mm).The distance between the upper end of the sphenoid sinus ostium and the top of the nasal cavity was 6.3 ±1.1 mm(4.4-8.3 mm),the distance between the lower end of the sphenoid sinus ostium and the anterior nasal spine was 57.8 ±3.1 mm(52.7-62.2 mm),the distance from the posterior nostril was 14.2 ±1.9mm(11.7-18.1 mm),and the angle between the sphenoid sinus ostium and the bottom of the nasal cavity was 30.8 ±1.3°(28.5-33.1°).3.The sphenoid septum was often partial to one side,3 to the left,2 to the center and 1 to the right,in which the left sphenoid septum was connected with the carotid prominence.4.There were 5 cases of sellar sphenoid sinus,1 case of presellar sphenoid sinus.The bone thickness of sellar floor was 0.9 ±0.8 mm(0.3-2.5 mm),and the distance between sphenoid sinus ostium and sellar floor was 15.3 ±1.3 mm(12.7-17.3 mm).There were 8sides(66.7%)of optic prominences,9 sides(75%)of carotid prominences,6(50%)sides of medial optic carotid recesses,8 sides(66.7%)of lateral optic carotid recesses.No bone fissures were found on optic prominences and carotid prominences,and 3 sides(25%)of Onodi cell were observed.5.This study revealed 83.3%(5/6)of the anterior intercavernous sinus,33.3%(2/6)of the posterior intercavernous sinus,50%(3/6)of the inferior intercavernous sinus,and 100%(6/6)of the basilar sinus.6.The width of the pituitary measured from the sphenoid sinus at the sellar floor level was 13.4 ±1.1 mm(11.9-14.7 mm)and the height was 6.2 ±0.8 mm(4.8-7.2 mm).7.In this study,no direct contact between internal carotid artery and pituitary gland was found,and the distance between them was 2.7 ±1.2 mm(1.1-4.7 mm).The distance between the two sides of the internal carotid artery was the closest at the level of tubercle sella,followed by that at the level of sellar floor and farther at the level of clivus,with distances of 12.8 ±1.2 mm(11.3-14.5 mm),16.6 ±1.6 mm(14.7-18.6 mm)and 19.7 ±1.9mm(16.8-22.2 mm),respectively.Conclusion: 1.The sphenoid sinus ostium was an important anatomic sign of endonasal transsphenoidal approach to the sellar region.The sphenoid sinus ostium can be found at about 14.2 mm above the posterior nostril,the medial part of the superior turbinate and the 5 mm near the midline,or according to the insertion of the nasal speculum in the direction 30.8° between the nasal septum and the bottom of the nasal cavity,entering 57.8mm along the nasal septum,and then deviating from the midline about 5 mm was the lower end of the sphenoid sinus ostium.2.The sphenopalatine artery and its branches of the posterior nasal septum artery were closely related to nasal bleeding during endonasal transsphenoidal surgery.It was easy to damage and cause bleeding when opening the anterior wall of the sphenoid sinus.3.The sphenoid sinus septum was often partial to one side and can not be used as the midline sign of the operation like the root of the vomer,but the position relationship between the septum and the sellar floor can be judged according to the preoperative imaging data,so as to locate the sellar floor.4.For sphenoid sinus with good pneumatization,clivus depression,optic prominence and carotid prominence can be used as reliable anatomical markers to judge the location of Sellar floor.For sphenoid sinus with poor pneumatization,neuronavigation can provide accurate location for surgery.5.The shortest distance between the bilateral internal carotid arteries was at the level oftubercle sella(about 12.8 mm).When endonasal transsphenoidal approach was used to remove tumors in the sellar region,it should be operated within its range to avoid damage to the internal carotid artery. |
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