Interdisciplinary Neurosurgery (Sep 2022)
Diaphragma sellae orifice ratio, is it an applicable anatomical index to determine the direction of the growth of pituitary macroadenomas?
Abstract
Objective: This study aimed to assess the morphology of the diaphragma sellae, its orifice, and calculation of an anatomical index: the diaphragma sellae orifice surface area to the diaphragma sellae surface area ratio (SAO/SAD) as a hypothetical measure that may affect the direction of the growth of pituitary macroadenomas. Methods:: In this anatomical study, fresh cadavers (age > 26 years) with intact skull base, in whom craniotomy was mandatory for identifying the reason of their death were included. After craniotomy, a photograph at the level of the diaphragma sellae was taken, and anatomical landmarks of the diaphragma sellae and its orifice were measured by Osiris software (Version 2.2; Digital Imaging Unit, University Hospital of Geneva, Switzerland). Descriptive statistics were expressed for anatomical parameters using the Statistical Package for the Social Sciences (SPSS, Version 11.5. Chicago, SPSS Inc.). Results: Of the 210 cadavers, 153 met the inclusion criteria (130 males, 23 females) and were dissected. The average anteroposterior diameter of the orifice was 4.75 ± 1.92 mm, the average lateral-to-lateral diameter was 5.26 ± 2.33 mm, and the average surface area of the orifice was 20.82 ± 15.70 mm2. The average anteroposterior diameter of the diaphragma was 8.26 ± 1.59 mm, the average lateral-to-lateral diameter was 11.07 ± 2.65 mm, and the average area of diaphragma sellae was 72.11 ± 23.54 mm2. Findings were categorized into four groups according to the SAO/SAD, and group A with the ratio of (SAO/SAD ≤ 0.25) was the most frequent ratio comprising 56% of the specimens. Conclusion: Diaphragma sellae with small openings was the most frequent type of diaphragma sellae. Among a wide range of factors affecting the direction of adenoma transgression, diaphragma sellae with small openings (SAO/SAD ratio ≤ 0.25) might have a contributing role on the deviation of the pituitary macroadenomas caudally and laterally; however, this is a hypothesis based on anatomical measurements of subjects who did not harbor pituitary adenoma, hence further complementary evaluations are necessary to assess the validity and applicability of this anatomical index.
