*9.1.1 Nasal stage*

Using 0-degree endoscopy, inferior, middle and superior turbinates are identified. Middle turbinate usually obstructs the access to sphenoidal sinus. To have unobstructed route, middle turbinate is typically displaced laterally, or resected if a wider view is needed, using a blunt dissector to create enough working space. After that, the choana is found on the inferomedial aspect of the view. Sphenoethmoidal

#### **Figure 10.**

*Patient positioned supine, with head slightly extended, monitors are placed to left of the patient (A). The surgeon standing on the right of the patient and the assistant on the surgeon's left side (B).*

recess is identified and sphenoid ostium is seen on the roof of the recess and the choana. Nasal septum the best landmark for midline identification.

## *9.1.2 Sphenoidal stage*

It starts with enlarging the sphenoidal ostium lateral and inferiorly. This step is usually undertaken by using chisel or high-speed drill. Care is taken to avoid injury to sphenopalatine artery the lies in the inferolateral direction. Posterior nasal septum is coagulated and detached from the sphenoidal rostrum. Anterior wall of the sphenoidal sinus now is exposed, circumferentially with bony removal using high-speed drill and sphenoidal rostrum is removed in fragments. It is important to perform a wide removal of anterior wall of sphenoidal sinus to avoid a narrow working space. Multiple sphenoidal septa can be seen inside the sinus and may need to be drilled. Care is taken septa drilling as one or more of the septa may be attached to carotid prominences.
