Anatomic Dissection of Arachnoid Membranes Encircling the Pituitary Stalk on Fresh, Non–Formalin-Fixed Specimens: Anatomoradiologic Correlations and Clinical Applications in Craniopharyngioma Surgery

Publication date: December 2017
Source:World Neurosurgery, Volume 108
Author(s): Pasqualino Ciappetta, Lorenzo Pescatori
BackgroundThe anatomy of the arachnoid membranes and cisternal spaces around the pituitary stalk has not been yet exhaustively described and understood. In this study, we performed a detailed anatomic study on fresh, non–formalin-fixed cadavers of the arachnoid membranes encircling the pituitary stalk and correlate our anatomic findings with magnetic resonance imaging (MRI).MethodsTen fresh, non–formalin-fixed, non–silicon-injected adult cadaveric heads were analyzed in this study. The membrane and cisterns that were studied for our study were as follows: 1) the diaphragma sellae and its dural components; 2) the basal arachnoid membrane; 3) the Liliequist membrane with its diencephalic and mesencephalic portion; 4) the medial carotid membrane; 5) the chiasmatic cistern; and 6) the pituitary stalk. MRI examinations of the sellar region were performed in 15 healthy volunteers (9 men, mean age 40 years; and 6 women mean age, 37 years) to visualize the arachnoid membrane encircling the pituitary stalk. MRI examinations were performed with a 3-T unit. A 3-dimensional constructive interference in steady state pulse magnetic resonance sequence was used.ResultsAll the membranes examined were visualized clearly in all the dissections performed. Their 3-dimensional organization around the pituitary stalk was clarified and confirmed by MRI.ConclusionsOur study gives a detailed description of the pituitary stalk arachnoid sheets on fresh, non–formalin-fixed cadavers. This technique allowed us to clearly identify a funnel-shaped arachnoid collar encircling the pituitary stalk and delimiting a distinct cisternal space belonging to the stalk itself.



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