FESS differs from traditional sinus surgery is that a thin rigid optical telescope, called an endoscope, is used in the nose to view the nasal cavity and sinuses. FESS generally eliminates the need for an external incision. The endoscope allows for better visualization and magnification of diseased or problem areas. This endoscopic exam, along with CT scans, may reveal a problem that was not evident before.
Another difference is that FESS focuses on treating the underlying cause of the problem. The ethmoid sinuses are usually opened. This permits direct visualization of the maxillary, frontal, and sphenoid sinuses and diseased or obstructive tissue can be removed if necessary. There is often less removal of normal tissue and surgery can frequently be performed on an outpatient basis without the need for painful packing that was used in the past. Generally, there are not external scars, little swelling, and only mild discomfort.
The goal of FESS is to open the sinuses more widely. Normally the openings to the sinuses are long narrow bony channels covered with mucosa or the lining of the sinuses. If this lining swells from inflammation, the sinuses can become blocked and an infection can develop. FESS removes some of these thin bony partitions and creates larger openings into the sinuses. After FESS, patients can still develop inflammation from allergies or viruses, but hopefully when the sinus lining swells, the sinus will still remain open. This will permit easier treatment of subsequent exacerbations with more rapid resolution and less severe infections.