The sphenoids are a pair of unequal air sinuses, separated by a bony septum which is rarely in the midline. Each has a small, round hole that opens into the posterosuperior part of the nasal cavity.
The pituitary gland is located inside the sella turcica, a round bony cavity that is separated from the sphenoid sinuses by a thin bone, the floor of the sella which forms part of the roof of the sphenoid sinuses.
On either side of the sphenoid sinus, are located a pair of intercommunicating venous channels (caverns) called the cavernous sinus.
Several important structures pass through the cavernous sinus between the venous channels:
-The internal carotid artery.
-The ophthalmic division of the trigeminal nerve (V1)
-The maxillary division of the trigeminal nerve (V2)
-The oculomotor nerve (III)
-The trochlear nerve (IV)
-The abducens nerve (VI)
Occasionally, the bony wall separating the internal carotid artery from the sphenoid sinus is very thin or absent. In such instances, the carotid is seen pulsating in the lateral aspect of the sphenoid sinus.
Through a sublabial approach, the muco-
perichondrium and mucoperiosteum of the nasal septum are elevated. The perpendicular plate of the ethmoid and septal cartilage are moved aside, to expose the rostrum (keel) of the sphenoid.
The intersphenoid septum is removed. The floor of the sella turcica is opened to expose the pituitary gland (P) and remove the tumor.
A chip of bone (or a piece of septal cartilage) is used to reconstruct the floor of the sella turcica. The perpendicular plate of the ethmoid and the mucoperichondrial / periosteal flaps are replaced in the midline. Nasal splints / packs are also placed in the nose.