The sinuses or paranasal sinuses are air filled cavities inside the facial bones of the skull. There are four more or less symmetrical pairs of sinuses, all in close relation to the nose, eye socket and brain and they all have small openings connecting them to the nasal cavity. The following video may help to picture it:

The anatomy

The inside anatomy of the sinuses are extremely intricate and complex and varies from person to person. The maxillary sinuses are located in the cheek bones between the upper teeth and the eye sockets. The frontal sinuses are in the forehead, above the eyes and in front of the brain; they vary a lot in size from being almost non-existent to filling the whole of the forehead. The ethmoidal sinuses consist of a cluster of air cells, each contained within a thin bony layer lined with mucosa – think of a honeycomb or the inside of an Aero chocolate bar to picture what they look like. They are located all along the nasal side of the eye sockets and directly underneath the brain and are separated from both these structures only by a very thin layer of bone. The sphenoidal sinuses are located next to the apex of the eye sockets, where the eye’s nerve exists the eye socket to the brain, and also just beneath the brain right in the centre of the head.

Acute, sub-acute and chronic

Being the larger cavities, the maxillary and frontal sinuses tend to cause more symptoms when obstructed or infected. Acute infection of the sinuses, known as acute sinusitis, often following on to a cold or flu, can usually be recognized by pain (in the cheeks, forehead or around the eye), fever and a yellow nasal discharge. Flu-symptoms carrying on for longer than 7-10 days can also indicate sinusitis. The majority of these acute infections will resolve on its own or with the help of a course of antibiotics within 10-14 days.

If sinusitis continues beyond 14 days, it is called sub-acute sinusitis and once it extends beyond 6 weeks it becomes chronic sinusitis. These infections can either be a low grade, continuous infection or reoccurring flare-ups of acute infections, typically feeling like a cold returning every 2-3 weeks. It can be associated with pain in the face, a yellow nasal discharge, a thick postnasal discharge, a blocked nose, sore throat, hoarseness and/or a chronic cough. The symptoms, however, tend to become vague and can be very difficult to distinguish from that of chronic rhinitis. Eventually a good physical examination by your ENT specialist and a CT scan of the sinuses will be needed to make the diagnosis (plain X-rays of the sinuses are of very little value).

What is the cause and how do we deal with it?

Sub-acute and chronic infection of the sinuses are most often caused by anatomical anomalies and variations which cause obstruction of the sinus openings (or ostia). When these sinus ostia are too small, the sinuses cannot drain and ventilate sufficiently and the sinus infection cannot resolve. Due to the location of the sinuses and their close relation to the brain, eye sockets and optic nerve, any stage of sinusitis can easily be complicated by spread of infection to any of these areas – complications which can be very serious, leading to blindness and even death. A CT scan will not only confirm the diagnosis of sinusitis, but will also reveal the abnormal anatomy involved and the extent of complications if present.

Treatment of sub-acute and chronic sinusitis will often involve surgery aimed at correcting the abnormal anatomy, permanently opening the blocked or narrow sinus ostia. Nowadays this surgery is done almost exclusively with an endoscopic approach, which means that the operation is done through the nostrils with the aid of a small telescope which enables the surgeon to view the intricate anatomy. This operation is called Functional Endoscopic Sinus Surgery (FESS) and is a very delicate and, in the right hands, a highly successful operation. Due to the delicate nature of the nasal mucosa, the small space in which the operation is done and the complexities and variations of the anatomy the outcome of the operation is highly dependent on the amount of care taken by the surgeon during the operation and the experience and dedication of the surgeon.

Is the operation safe? Is it successful?

As mentioned already, the sinuses are situated in very close relation to the floor of the brain, the eye socket (orbit), some of the eye muscles and the optic nerve. During endoscopic surgery, the surgeon can only see the inside of the sinuses and it can become very difficult to correctly judge the confines and borders of the sinuses. Damage to the surrounding structures becomes a real possibility, especially when operating on the sinuses which are deeper inside the head (the middle and posterior ethmoidal and the sphenoidal sinuses) and those with difficult access (in particular the frontal sinuses). Fortunately we have additional technology available to enable the surgeon to follow his instruments inside the sinuses and view, on a computer containing the patient’s pre-loaded CT scan, the location and surrounding relation of the instrument and the progress of the operation. This adds a tremendous advantage to the safety and thoroughness of the operation. This technology is called surgical navigation or stereotactic surgery. Personally I insist on using surgical navigation, which I have readily available at Netcare Vaalpark Hospital, whenever I have to operate on the abovementioned sinuses.