structures lie within the transsphenoidal surgical field?
The sella turcica, within the body of the
sphenoid, pro-vides bony protection for the pituitary gland. The diaphragma
sella is a roof of dura pierced by the pituitary stalk with its arachnoid,
which extends to the hypothala-mus. The cavernous sinus surrounds the walls of
the sella and contains the cavernous portion of the internal carotid artery as
well as cranial nerves III, IV, and VI. The optic nerves converge above the
diaphragm to form the chiasm. Arterial bleeding during transsphenoidal
hypophysectomy may be from the carotid artery or its branches and venous
bleeding arises from the cavernous sinus. If excessive bleed-ing from the
cavernous sinus occurs, it may be difficult to control. Temporary or permanent
packing of the sinus may be necessary.