The anatomical study on precise localization of microsurgery via single-nostril transsphenoidal approach

Objective To anatomically study the transsphenoidal approach via single nostril, providing anatomical data for precise localization of secure microsurgical resection of pituitary adenomas via single-nostril transsphenoidal approach.Methods The significant anatomical marks for precise localization of microsurgery via single-nostril transsphenoidal approach,such as the superior extremity of posterior margin in nasal septum,ostium of sphenoidal sinus,sphenoidal crest,vomer,sphenoid sinus interval and sellar floor etc were observed anatomically and measured on 20 adult wet cadaveric heads. Results(1)The average distances from anterior nasal spine to sellar floor,ostium of sphenoid sinus, internal carotid artery(ICA)and the optic nerve were respectively(70.20±0.98)mm,(57.29±0.68)mm, (69.66±0.74)mm and(70.95±1.03)mm.(2)The average distances from the ostium of sphenoid sinus to sellar floor,optic nerve,ICA,midpoint oftuberculum sellae and dorsum sellae,and the inferior margin of vomer dissociative surface(interface between posterula and pharyngeal portion)were respectively (14.62±0.80)mm,(13.25±0.99)mm,(14.38±0.82)mm,(15.03±1.21)mm,(25.24±1.08)mm and(17.21±0.59)mm.(3)Among the 20 cases,bony plates of sellar floor in 17 cases developed protuberances inside sphenoid sinus,which could be regarded as the sign determining intrasphenoidal sellar floor.(4)The relationships between the superior extremity of posterior margin in nasal septum,sphenoidal crest, posterior margin ofvomer and the central portion ofsellar floor were vertical.Conclusion The ostium of sphenoid sinus is an anatomical mark of great importance for localizing the anterior wall of sphenoidal sinus.The superior extremity of posterior margin in nasal septum,sphenoidal crest and posterior margin of vomer can be regarded as the marks for localizing the midline of sellar floor.