Transnasal Endoscopic Surgery Of The Sellar Region, The Pterygopalatine Fossa And Related Structures: Anatomy And Surgical Technique Study

Transnasal endoscopic surgery is a new technique for the diseases of skull base and has developed rapidly in the past decades.However,the development of the technique is limited by lacking convenient,practical anatomical study and suitable surgical instruments.The three-dimensional anatomy of the sellar region,the pterygopalatine fossa and related structures were studied,and a noval surgical technique-the assistant technique of the transnasal endoscopic surgery named by our reaseach team was explored.The first part:Transnasal endoscopic surgery of the sellar region,the pterygopalatine fossa and related structures:anatomical study1.Designing a new tool,which can measure angle and distance simultaneously based on the MicronTracker binocular visual navigation system.The tool's accuracy had no statistical difference as compared with vernier caliper and turntable.The frontal bone plane and sagittal plane are used as datum plane,the lateral margin point of nasal spine and middle point of anterior border of basis nasi are used as datum point,then the distance and angle are used as the anatomical structure's localization parameter,the method was proved logically by math principle. In order to test the new tool,we measure some angles and distances on dry adult cranium specimens with it.We can get the pitching angle,direction angle and distance from the tool conveniently.The relationship between the landmarks of the skull base, the nasal cavity and the frontal bone plane,the sagittal plane is stable,then the planes may be used as the datum plane to look for the landmarks in the anatomic study,even in transnasal endoscopic skull base surgery in the future.2.Studying the anatomical characteristics and three-dimensional relation of the sellar region.The basis nasi plane and median sagittal plane are used as datum plane,S point (the lateral margin point of nasal spine) and M point(maxillary line midpoint) are used as datum point to orientate the structures,inferior limbus of aperture of sphenoidal sinus,vertex of sphenoidal sinus anterior ridge,medial point of the common tendinous ring medial wall,Optic—carotid recess,medial point of sellar turcica anterior limbus,medial point of sphenoidal sinus posterior wall superior limbus,lateral point of sphenoidal sinus posterior wall superior limbus,medial vertex of clivus posterior limbus,lateral vertex of clivus posterior limbus are useful landmarks or anchor point.We used 3D-max9.0 and AutoCAD2008 to set up three-dimensional anatomical model of the anatomical structures,which can rotate and move randomly,be easy to observe,display and study the moving trajectory of surgical instruments.We found that,gasification degree of sphenoidal sinus is varied, which is an important factor on transnasal endoscopic surgery;being familiar with the basic triangle of posterior wall of sphenoidal sinus is helpful in the transnasal sphenoidal surgery.The three-dimensional anatomical model of sphenoidal sinus enriched the content of the"#"shape subdivision and made it guide surgery more conveniently.Knowing the three-dimensional anatomical relationship of C5 and C4 of internal carotid artery is helpful to reduce complications.3.Studying the anatomical characteristics and three-dimensional relation of the pterygopalatine fossa and related structures.The basis nasi plane and median sagittal plane are used as datum plane,S point and AM point(anteroinferior wall midpoint of maxillary sinus) are used as datum point to orientate the structures,the A point(a concave of the maxillary sinus posterior-medial wall),superior limbus of sphenopalatine foramen anterior wall,the first branch root of internal maxillary artery,superior border of greater palatine canal, middle point of the vadian canal anterior limbus,middle point of the foramen rotundum,lateral point of the pterygoid root anterior limbus,anterior limbus of foramen ovale,anterior limbus of foramen lacerum,anterior limbus of the internal carotid artery posterior bend,anterior limbus of the internal carotid artery anterior bend are useful landmarks or anchor points.We used 3D-max9.0 and AutoCAD2008 to set up three-dimensional anatomical model of the anatomical structures,which can display the 3D—relationships about the structures.We find a rule of the branches and course of maxillary artery.It has a good application prospect for endoscopic transnasal/maxillary-peterygopalatine fossa approach to cavernous sinus,which deserves further study.The second part:The assistant technique of the transnasal endoscopic surgery stt1.Designing an assistant system of the transnasal endoscopic surgery.The symtem are including endoscope holder,electricity-controlled irrigation and suction system,nasopharynx blocking aerocyst and soft linear bipolar coagulator. With the system,we can solve the problems such as singlehanded operation,lens stained by blood and electric coagulation in the deep operation region in the transnasal endoscopic surgery.We manufactured all the instruments successfully.2.Performing a mimic transnasal endoscopic surgery in the nasal cavity of a mongrel dog using the instruments.We have set up a reasonable and efficient operation mode with the instruments, namely one hand operates and moves the endoscope,the other hand keeps the operation field and the endoscope clear with the electricity-controlled irrigation and suction system.The mimic surgery proved the system could help us to operate conveniently by two hands and keep the endoscope clear,to improve the accuracy and efficiency in transnasal endoscopic surgery.