Functional Endoscopic Sinus Surgery (FESS)

The para-nasal sinuses are air filled spaces in the bones of the skull, which connect to the nasal cavity. They are lined by specialized cells called mucosa. Sometimes the pathways that connect the sinuses to the nose become blocked and the mucosa becomes unhealthy. Pressure abnormalities can occur which cause pain. Sometimes these blocked sinuses become infected causing “acute” sinusitis with fever, severe facial pain and unpleasant mucous from the nose.

FESS stands for Functional Endoscopic Sinus Surgery. It is the modern approach to sinus surgery using endoscopes and minimally invasive techniques. The basic concept behind this surgery is to try and re-establish the natural ventilation pathways between the nasal cavity and the sinuses, and so improve the “function” of the nose. It also allows drugs in the form of nasal sprays, to penetrate further into the sinuses, which are opened to the inside of the nose.


The surgery usually consists of removing very small amounts of tissue from the nose, but from critical areas, through which the sinuses drain. Some patients with sinusitis also develop nasal polyps and these are also removed during FESS. In some cases it is also necessary for the surgeon to straighten the nasal septum (the midline partition between the two nasal cavities) in order to gain access to the sinuses.

After suitable vasoconstriction using ephedrine, the middle turbinate is identified. This is the most important landmark for the procedure. On the lateral wall of the nose at the level of the anterior end of the middle turbinate lies the uncinate process. This is removed, exposing the ethmoid bulla and the opening called the hiatus semilunaris, into which the frontal and maxillary sinuses drain.

The anterior ethmoid air cells are then opened, allowing better ventilation but leaving the bone covered with mucosa. Following this, the maxillary ostium is inspected and, if obstructed, opened by means of a middle meatal antrostomy. This minimal surgery will often be sufficient to greatly improve the function of the osteomeatal complex and therefore provide better ventilation of the maxillary, ethmoid and frontal sinuses.