Anatomic Study Of The Sphenoidal Sinus And Its Application In Pituitary Adenoma Resection By Trans-single Nostril And Transsphenoidal Approach

Accompanied the development of neuroimaging technology, the detective rate of pituitary adenoma raised year by year. Schloffer(1907)was the first doctor who resected pituitary adenoma by transsphenoidal approach. But having no antibiotic drug and microsurgical technique, this method was not applied widespread in clinic for high complication and death rate. Through Cushing, Guioty especially Hardy's improvement in the transsphenoidal microsurgical technique, the transsphenoidal approach has became one of the most widespread applied methods to resecte pituitary adenomas. Accompanied the establish of microinvasive concept and the skillness of the transsphenoidal microsurgical technique day by day. To decrease complications and shorten the operation time, doctors improved the modus of the transsphenoidal approach unceasingly. The trans-single nostril and transsphenoidal approach has advantages of no skin or mucous membrane incision, few complications and save time. It had become very popularous in neurosurgeons.To resecte pituitary adenomas by the transsphenoidal approach, we must fit-into the sphenoidal sinus according to the anatomic midline strictly and the speculummust aim at the bottom of the sella turcica all along. Fit-into the latero-side could injure the internal carotid artery and the cavernous sinus. Fit-into the front side could enter the anterior cranial fossa then injure the optical nerve and brain tissue. Fit-into the back side could exceed the clivus and injure the brain stem. All these might cause serious consequence. Using C-arm in operation might hint the direction of the speculum, but it always took more than one photograph and added the radioactive ray pollution. Neuronavigation could provid realtime localization with three-dimensional information in operation, accurately localize anatomic midline, the anterior wall of the spheniodal sinus, the floor of sella, the internal carotid artery, the optical nerve and other important structures, but only few hospital had this expensive equipment and this added the cost of hospitalization.We observed and measured the sphenoid sinus on 8 fresh adult cadavers and 50 imaginations of adult MRI, studied the anatomic characters of the sphenoid sinus. In order to provid essential anatomic characters for the trans-single nostril and transsphetnoidal approach by took full use of information from MRI. All samples had no abnormalities and external injury, had no foreign substance and inflammation in nasal cavities. All MRI had complete face on its anteroposterior axes imaginations and well gasified sphenoid sinus. All cadavers was sawed from center anteroposterior axes. Under the condiction of anteroposterior axes, the root of columella nasi was defined as point O, the inferior border of the spheniodal sinus's anterior wall was defined as point B, the superior border of the spheniodal sinus's anterior wall was defined as point C, the midpoint of the sella floor was defined as point D. Marked each point on the anteroposterior axes imaginations of MRI accordingly. Line OA paralleled processus alveolaris maxillae and passed point O. ZAOB \ ZAOC' and ZAOD' was the supplementary angle of ZAOB> ZAOC and ZAOD respectively. Line OE was the bisector of ZB' OD' . Observed the gasification of the spheniodal sinus, the appearance of the super sphenoid-eth moid cell, the deviation of the middle septum of sphenoid, the appearance of the concomitant and the horizontal septum ofsphenoid. Measured ZAOB\ ZAOC\ ZAOD\ ZAOE , OB, BC.In 8 fresh adult cadavers: Each processus alveolaris maxillae had a level facies ossea. ZAOB' (43.2±4.3)°, ZAOC' (22.9±3.0)°, ZAOD' (35.4±4.1)°, ZAOE (39.3±3.9)°, OB(66.3±3.6)mm, BC(20.9±1.5)mm. 2 cases had super sphenoid-ethmoid cell. 1 cases did the spetums locate in the median sagittal section, 4 cases deviated to the left, 3 cases deviated to the right, hi 50 imaginations of adult MRI: ZAOB' (44.1±5.5)°, ZAOC' (25.7±6.4)°, ZAOD' (34.2±5.9)°, ZAOE (39.1±5.6)°, OB(68.7±4.9)mm, BC(23.3±3.1)mm. 15 cases had super sphenoid-ethmoid cell. 14 cases did the spetums locate in the median sagittal section, 19 cases deviated to the left, 17 cases deviated to the right. Towards two-sample t-test and Chi-Square test. P>0.05.There were no obvious difference in two groups.The speculum angle was defined as included angle of its inferior border and line OA. If the angle exceeded ZAOB' , you would exceed the clivus then injure the brain stem. If the angle was less than ZAOD' (especially ZAOC' ), you would fit-into the super sphenoid-eth moid cell or the anterior cranial fossa then injure the optical nerve and brain tissue. Therefore, the speculum angle must be less than ZAOB' and exceed ZAOD' . Thus would ensure you to aim at the bottom of the sella turcica all along. The depth that the speculum enter the nasal cavity could not exceed the length of line OB. Too deep would fit-into the sphenoid then coused unnecessary injury. The height which the anterior wall of the spheniodal sinus was opened could not exceed the length of line BC.The following was our methods: According to average value of ZAOE, made a standard angle of 39° using a conimeter. Measured ZAOB' > ZAOC' , ZAOD' > ZAOE >. OB, BC according to the anteroposterior axes imaginations of MRI preoperation. Marked the depth that the speculum would enter the nasal cavity according to line OB. All cases were trans-right nostril approach. Rejoinined the speculum, when it entered the nasal cavity at the mark, Adjusted the direction of the speculum by standard angle of 39°, readjusted by ZAOE. Then opened the speculum,fracted the nasal septum from its root in front of the gab of the sphenoid sinus and pushed it to the opposite side. Pushed away the mucosa in front of the sphenoid sinus. Opened the anterior sphenoidal wall below the gab of the sphenoid sinus. The range was about 1.5cmx 1.5cm. Be careful not too supravergence. Remained 2mm sclerotin of the sphenoidal crest to notate of anatomic midline. Eliminated the separation and the mucosa of the sphenoid sinus. Then the sellar floor was exposed. Used C-arm to localize before opening the sellar floor. We localized 11 cases using standard angle of 39° in 2004. All cases were localized accurately at one time confirmed by C-arm. Opened the sellar floor. The range was about l.Ocmx 1.5cm. Puncted into the sella to evacuate aneurysm and internal carotid artery. Cut the dura mater membrane of the sellar floor with the shape of "+". Then the grey adenoma was exposed. Erased the intrasellar adenoma bit by bit with cricocurette. Then resected the intrasellar adenoma from its latero and anodic side. For the suprasellar adenoma, increased the intracranial pressure by added the thoracic cavity pressure using anaeshetic machine or compressed both jugular vein, thus the suprasellar adenoma would fall into the intrasella, then erased it bit by bit. Acted lightly and softly when erased, snuffed or resected the adenoma intrasellar. Be careful not to breakthrough the sellae diaphragma and cause the leakage of cerebrospinal fluid. Avoided injuring the cavernous sinus, the sellae diaphragma, the optic nerve, the internal carotid artery. Cleared the tumor bed. Stopped bleeding thoroughly. Sealed the sellar floor with gelatin sponge and EC ear-brain gelatin. Pulled out the speculum. Reseted the nasal septum with the shaft of the gun-form pliers from the opposite nasal cavity. Plugged the operative nasal cavity with iodoform gauze.It was an effective, less trauma surgery for pituitary adenoma resection by trans-single nostril and transsphenoidal approach without or with less complications. Made full use of MRI preoperation . Measured ZAOB\ ZAOC'> ZAOD\ ZAOE % OBn BC. Observed the gasification of the spheniodal sinus, the appearance of the super sphenoid-eth moid cell, the deviation of the middle septum of sphenoid,the appearance of the concomitant and the horizontal septum of sphenoid. Analyzed and measured individually preoperation. Adjusted the direction of the speculum by standard angle of 39°, readjusted by Z^AOE. Would make it more safely to open the anterior wall of the spheniodal sinus and the sellar floor in operation. The depth which the speculum entered the nasal cavity could not exceed the length of OB. The height which the anterior wall of the spheniodal sinus was opened could not exceed the length of BC. The middle septum of sphenoid could not be regarded as the only bone mark directing the transsphenoidal approach to the hypophysis. The sphenoidal crest and the vomer bone was the notation of anatomic midline. As C-arm localization was the gold standard, We suggested that you had better use C-arm to localize before opening the sellar floor. Thus could avoid causing unnecessary injury.