RESUMO
Objective To define the exposure extent of the ventral part of the clivus under the extended endoscopic endonasal approach,important anatomical landmarks and the distance between each other via this approach.Methods Twenty formalin-fixed intact adult human head-neck specimens,in which only the arteries was injected with red latex,were longitudinally and coronally dissected to evaluate the surgical key steps and the advantages and limitations via extended endoscopic endonasal approach and selected measurements were obtained.Five fresh and intact head-neck specimens were used to perform analogical operation via the extended endoscopic endonasai approach to the ventral part of the clivus.The surgical exposure of main landmarks in the clivus was extended under endoscope and microscope,and the interactions and distances between the landmarks were studied.ResultsAnatomic landmarks of the approach included the middle turbinate,the choana narium,the Eustachian tube ostium,and the nasopharynx mucosa,the aperture of sphenoidal sinus,the longus capitis,the longus colli,the basion,the internal carotid artery and the sphenopalatine artery.The distances between the anterior nasal spine and both the pharyngeal tubercle and the basion were (78.23±2.58) mm and (89.60±2.52) mm,respectively.The shortest distance exposuring ventral region of clivus completely should be (89.60+2.52) mm.The exposure in the inferior wall of sphenoid sinus and the lower clivus was limited by pterygoid canal and foramen lacerum,and the average distances from the median line to them were (9.22±0.52) mm and (9.70±0.70) mm,respectively; no significant difference between the left and right was found (P>0.05).Conclusion knowing the anatomical structure,understanding its connection with the brain tissue and its exposure extent of the ventral part of the clivus are the major problems that need to be solved in the extended endoscopic endonasal approach.
