Functional Endoscopic Sinus Surgery (FESS) & Polypectomy

What the Operation Is

Functional Endoscopic Sinus Surgery (FESS) is an operation performed entirely through the nostrils using small endoscopes and instruments. The goal is to widen the natural drainage pathways of the paranasal sinuses (the air-filled cavities in the bones of the face) so that mucus can clear normally and steroid sprays and washouts can reach the sinus linings. In patients with nasal polyps, the polyps are also removed during the same operation — a polypectomy.

The sinuses sit very close to important structures: the eye, the brain, the carotid artery and the olfactory nerve fibres at the top of the nose. FESS therefore carries a small number of important additional risks not present with septoplasty alone. This is why I insist on a CT scan of the sinuses before this operation — an MRI scan does not give the bone detail needed to plan the operation safely.

Risks & Complications

The risks below are additional to the standard nasal surgery risks of bleeding, crusting, swelling, post-operative congestion, and infection — all of which are described in detail in the septoplasty consent page. Please read that page as well.

1. Damage to the bone separating the eye from the nose (lamina papyracea)

Each ethmoid sinus sits next to the eye, separated only by a paper-thin bone called the lamina papyracea. Inadvertent breach of this bone is uncommon (national risk approximately 0.6%) and usually causes only a black eye after surgery. In rare cases, deeper dissection into the orbit can damage the muscles that move the eye, cause double vision, or — in the worst case — affect the optic nerve and threaten sight. This is why a pre-operative CT scan is mandatory and not optional. Damage to the eye has not happened in my surgical career, but I include this risk because you have a right to know it exists.

2. Damage to the bone separating the nose from the brain (skull base)

The roof of the ethmoid sinuses and the cribriform plate separate the nose from the front of the brain. Inadvertent breach of this bone causes a leak of cerebrospinal fluid (CSF) from the nose. This may need to be repaired surgically. If a CSF leak develops and becomes infected, there is an additional risk of meningitis. A CSF leak or meningitis has not happened in my surgical career.

3. Numbness of the cheek

A nerve (the infraorbital nerve) sometimes runs through the maxillary sinus and could theoretically be irritated during operations on this sinus, producing numbness of the cheek. I have never seen this happen, but it is a theoretical risk.

4. Polyp recurrence

Removing polyps surgically opens the space and allows steroid sprays to work more effectively. Without nasal steroid sprays after surgery, there is approximately a 50% chance that polyps will grow back. Even with diligent use of steroid sprays, a smaller proportion of patients have recurrence, and repeated polypectomy may be required over the years. Biological therapies (such as dupilumab) are now available for patients with severe recurrent polyps, and may be considered alongside surgery.

5. Permanent loss of sense of smell

There is a risk of a permanent inability to detect any smells after this operation, related to disturbance of the olfactory nerve fibres at the top of the nose. This is very unlikely and has not happened in my surgical career. Many patients with chronic sinusitis already have impaired smell before surgery, which typically improves after FESS — but there is no guarantee, and complete loss is a small possibility.

6. Standard nasal surgery risks

All the standard risks described in the septoplasty consent page apply here too — bleeding (with the occasional need for nasal packing), infection, crusting and post-operative congestion for six to twelve weeks, adhesions, and the rare risks of nasal infection spreading to the brain or causing septal perforation. Saline washouts, steroid sprays, and prevention of infection are just as important after FESS as after septoplasty.

7. Anaesthetic risks

As with any operation under general anaesthetic, there are standard risks. The anaesthetist will discuss these separately.

Aftercare

Aftercare is essentially the same as for septoplasty — please read the septoplasty aftercare section. The most important elements are:

• NeilMed Sinus Rinse four times daily — the single most useful intervention.
• Sterimar Hypertonic spray every few hours between rinses.
• Steroid spray as prescribed — usually continued long-term in polyp patients.
• Two weeks off work.
• No flying for two weeks (medical advice); check travel insurance for the exclusion period.
• No straining-type exercise for two weeks.

When to Call the Hospital or Attend A&E

• Persistent clear watery fluid from one nostril, especially when bending forward — possible CSF leak.
• Severe headache, neck stiffness, photophobia — possible meningitis.
• Black eye, double vision, or any visual disturbance — needs urgent ophthalmic assessment.
• Heavy nosebleed that does not settle.
• Worsening pain or tenderness over the cheek or forehead, fever, or foul discharge — possible infection.

Booking, Consent and Next Steps

If you are considering FESS or polypectomy, the secretarial team can arrange a consultation. A pre-operative CT scan of the sinuses is essential before this operation can be planned. See also Sinusitis and Blocked Nose.