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Functional Endoscopic Sinus Surgery (FESS)



This is a procedure that aims to widen the passages between the sinuses and the nose so that the lining of the sinuses do not become congested, and nasal mucous cannot get trapped. Nasal polyps are also removed at the same time during FESS.


Sinuses are air filled spaces located within the bones at the front of our head and skull and connected to our nose.  The sinuses play a vital role in how we breathe, as they allow the flow of mucus from their lining, or mucous membranes, into our nose and throat.



Sinusitis is a condition where the lining of your sinuses becomes inflamed, swollen, blocked, or infected. This blockage traps air and mucous within the sinuses that can become uncomfortable and/or painful, associated with the constant feeling of a blocked nose. Other symptoms include persistent nasal irritation, post nasal drip, and a reduced sense of smell and taste.


Sinusitis can be sub-divided into:

  • Acute Sinusitis

Sinusitis which resolves within two to three weeks on average but can last up to twelve weeks and may be triggered by an infection. It is often brought on after a head cold.

  • Chronic (Rhino) Sinusitis

Sinus symptoms which lasts longer than twelve weeks.



  • Frontal headaches,

  • Blocked or stuffy nose,

  • facial tenderness,

  • pressure or pain in the sinuses, the ears, behind your eyes and/or teeth/jaws

  • fever,

  • cloudy, green or yellow nasal discharge

  • feeling of nasal stuffiness,

  • sore throat,

  • cough,

  • loss of sense of smell and taste,

  • bad breath.



Chronic Rhinosinusitis can sometimes be difficult to differentiate from allergic or chronic rhinitis, but your ear nose and throat consultant will take a detailed history from you and examine your nose with a small camera (nasoendoscope) to observe the lining of the nose and sinus as well as looking for blockages. Other investigations may also be performed such as allergy tests, and a CT scan of the sinuses to determine the extent of sinus disease and identify relevant sinus anatomy necessary for surgical planning.


Acute Sinusitis is self-limiting and usually resolves within 2 to 3 weeks. The symptoms can be managed with analgesia, antibiotics, nasal or oral steroids. 


In a small number of patients with disabling symptoms, an operation called Functional Endoscopic Sinus Surgery (FESS) may be required. It is important to recognise that FESS is not a ‘cure’ for chronic rhinosinusitis, but instead a useful treatment after the failure of ‘maximum’ medical therapy. FESS relieves most of the symptoms outlined above and facilitates the delivery of medication to the nose and sinuses that still needs to be used on a regular basis after surgery.


In some rare cases, if left untreated acute or chronic sinusitis may cause complications such as infection spreading to the eye socket (facial or orbital cellulitis) or brain (meningitis).


The term functional means that the surgery aims to return the sinuses back to working order, whilst endoscopic means that it is minimally invasive sinus surgery, all performed through the nostril, with no external cuts to the nose or face. FESS is routinely performed under a general anaesthesia as a day case procedure.  The sinus passages are widened by removing small amounts of bone or swollen sinus lining, to relieve the sinus blockage. Other reasons why your sinuses may be blocked include a deviated (bent) nasal septum, or nasal polyps, and these can be addressed at the same time during FESS.



Most patients do not require a nasal pack immediately after surgery, because any bleeding spots are dealt with during the operation. You will be advised not to blow your nose for at least a week following your procedure. Your surgeon will also prescribe saline salt water rinses for your nose that needs to be used on a regular basis at least twice a day, in addition to nasal steroid drops. Depending on the severity of sinus disease, a short course of oral steroids and antibiotics may be required. You will be advised to rest for up to two weeks following your operation and will need to be off work during that time.



FESS is usually a safe operation, but as with any surgery, complications can arise. These include pain, minor bleeding, infection at the site of surgery, or bleeding that requires a return to hospital +/- emergency surgery. Complications related specifically to sinus surgery are very rare and these could include:


  • Damage to the eye socket +/- blindness (less than 1 in 500 risk) – the sinus is very close to the wall of the eye socket (or orbit) which could accidentally be opened, causing bleeding within the orbit, or damage to muscles of the eye. Symptoms may include minor bruising or swelling around the eye that is usually self-limiting and does not require any specific treatment, however it is important not to blow your nose. In rarer, more severe situations, visual disturbance or blindness may occur, and it is important that you report any double vision or loss of sight as a matter of urgency.


  • Cerebrospinal fluid (CSF) leak (less than 1 in 200 risk) - The sinuses are very close to a thin bone at the base of the brain, and this may be accidentally injured during FESS, exposing the lining of the brain within the nose. If a CSF leak is identified during surgery an attempt will be made to repair it, if possible, at the same time. Occasionally a CSF leak may not be obvious during surgery, but instead patients may complain of a persistent, clear, watery nasal discharge, especially when bending the head forward.  This should be brought to the attention of your ENT surgeon. On very rare occasions (less than 1 in 1500 risk) an infection can spread from the nose or sinuses into the lining of the brain causing meningitis, and although uncommon, will require urgent attention and treatment.

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