Reappraisal of the dimensions of the diaphragma sellae

Abstract

Morphometric dimensions of diaghragma sellae influence the extent of instrumentation and tumour exposure in the hypophyseal fossa, and the degree of compression of visual fibres from an expanding pituitary tumor. The dimensions show inter-population variations but data from Africans is scarcely available in literature. We aimed to investigate the morphometric dimensions of diaghragma sellae in an adult Kenyan population. One hundred and forty wet open crania (96 males, 44 females) obtained from the Department of Human Anatomy, University of Nairobi were studied. The shape of diaphragma sellae was classified as round or elliptical (elliptical was further classified as coronal elliptical or sagittal elliptical). The sagittal and coronal dimensions of the sellae were also determined. The diaphragma sellae was round in 60% of cases, coronal elliptical in 34% and sagittal elliptical in 6%. It was significantly wider in females than males (10.26+2.61mm vs 8.37+1.82mm respectively), p= <0.05. It was also wider in the coronal than sagittal dimension (20.01+2.00mm vs 18.45+2.97mm) and this difference was statistically significant. The significantly wider diaphragma sellae in females may provide better tumor exposure during surgery and may protect the visual fibres from a suprasellar extension of an expanding pituitary tumour. On the other hand, the larger coronal than sagittal sellae dimension should be considered during instrumentation in the hypophyseal fossa to avoid inadvertent neurovascular injury.

Key words: Diaphragma sellae, Morphology, Morphometry