Endoscopic sinus surgery (FESS)
Sinus surgery can bring real relief in chronic sinus disease — but it is a considered step that comes after medical treatment, not a first move. This guide explains what FESS is, who it helps, and what to expect.
Medically reviewed by Dr. Marwan Alhalalmeh, ENT Specialist · Last reviewed: 2026-06-17
What FESS is
Functional endoscopic sinus surgery (FESS) is the standard operation for sinus disease that has not responded to medical treatment. Working through the nostrils with a thin endoscope and fine instruments, the surgeon gently opens the natural drainage pathways of the sinuses and clears blockage or diseased tissue. There are no external cuts and no change to the shape of the nose.
The aim is “functional”: to restore the sinuses’ own ventilation and drainage so they can clear normally and respond better to ongoing treatment — not simply to remove tissue.
Medical treatment comes first
Surgery is considered only after appropriate medical treatment has been given a fair trial and has not controlled the symptoms. A CT scan of the sinuses is usually used to map the anatomy and confirm the extent of disease before any decision about surgery. Depending on the cause, medical treatment usually includes:
- Saline rinses to clear and soothe the nasal lining
- Steroid nasal sprays to reduce inflammation
- Treating underlying allergy where it contributes
- A course of medication for infection in selected cases
Who it may help
FESS is most often considered in the situations below. Where a deviated septum is also contributing to the blockage, septoplasty is often carried out at the same time to improve access and airflow:
- Chronic rhinosinusitis — sinus inflammation lasting twelve weeks or more — that persists despite medical treatment, with or without nasal polyps
- Recurrent acute sinus infections in selected cases
- A structural blockage, or a complication, that needs to be addressed surgically
What the procedure involves
FESS is usually carried out under general anaesthetic as a day case or with a short hospital stay. Because the work is done entirely through the nostrils with an endoscope, there is no external wound and no facial bruising. The length of the operation depends on how many sinuses are involved and whether a septoplasty or polyp removal is done at the same time. Your surgeon will explain exactly what is planned for your case beforehand.
Recovery, in general terms
In the first week or two it is normal to have a blocked, congested nose, some crusting, and a little blood-tinged discharge as the lining heals. Saline rinses are usually recommended to keep the area clean, and a follow-up visit may be used to gently clear crusts. Most people are advised to avoid forceful nose-blowing and strenuous activity for a short period. Specific aftercare varies, so follow the instructions you are given.
Surgery is part of ongoing care
It is important to have realistic expectations. FESS improves drainage and makes the sinuses easier to manage, but it is not a one-off cure that removes the need for any further care — particularly with nasal polyps or allergy, where the underlying tendency to inflammation remains. In these cases, medical treatment such as steroid sprays and rinses usually continues after surgery to keep symptoms controlled and reduce the chance of problems returning. Surgery and ongoing medical care work together.
When to seek urgent care
After sinus surgery, seek medical help straight away if you have:
- Heavy or persistent bleeding from the nose
- Changes in vision, double vision, or swelling and bruising around an eye
- A severe headache with a stiff neck, or a high fever
- Persistent clear, watery fluid dripping from the nose
Common questions
Will sinus surgery cure my sinusitis for good?
It is best seen as a major improvement rather than a permanent cure. FESS restores the sinuses’ drainage and makes them easier to control, but where allergy or polyps are involved the underlying tendency remains, so ongoing medical treatment usually continues afterwards to keep symptoms in check.
Why do I need to try sprays and rinses before surgery?
Because for many people medical treatment controls the problem without an operation. Surgery is reserved for sinus disease that persists despite a fair trial of appropriate medical treatment, which is why sprays, rinses and treating any allergy come first.
Is FESS painful, and will there be scars?
The surgery is done entirely through the nostrils, so there are no external cuts or facial scars. Afterwards the nose feels blocked and congested for a week or two rather than sharply painful, and this is managed with simple measures and saline rinses.
Will I be asleep during the operation?
FESS is usually carried out under general anaesthetic, so you are asleep and feel nothing during the procedure. It is commonly done as a day case or with a short stay, and your surgeon and anaesthetist will discuss the details with you beforehand.
Further reading
General information about this topic from an independent health authority:
NHSHave questions about treatment?
Book a consultation with Dr. Marwan to discuss your symptoms and the options that are right for you.
Book a consultationThis guide is general information, not medical advice. Symptoms and the right treatment vary between individuals; only an in-person assessment can determine what is right for you or your child.