Allergy, Nose & Sinus

All you need to know about Functional Endoscopic Sinus Surgery (FESS)

February 10, 2020
Normal Sinusitis sinuses

FESS stands for Functional Endoscopic Sinus Surgery. It is a minimally invasive surgery of the nose and paranasal sinuses. The aim of the surgery is to relieve sinus obstruction and restore the physiological function of the nose and sinuses (Fig 1a & b)






Fess Figure

Fig 1a&b – How FESS is performed



When (or Why) do I need FEES?


Your ENT surgeon may recommend FESS if you have:


  1. Rhinosinusitis (infection of the sinuses) that has not responded to medical management
  2. Recurrent rhinosinusitis
  3. Complications from rhinosinusitis
  4. Nasal polyps (benign inflammatory outgrowths from the lining of the nose or sinuses)
  5. Mucoceles (bag of mucous in the sinuses that may expand and erode surrounding structures)



What is the difference between ESS and FESS?


ESS or Endoscopic Sinus Surgery is a broader term which covers any endoscopic surgery of the nose and sinuses, including FESS. ESS may not be functional (e.g preservation of mucosa) and some indications for ESS include resection of sinonasal tumour, resection of skull base or brain tumour through the nose and sinuses, surgery of the eye through the nose and sinuses and surgery on the nasal septum.



How is FESS done?


The operation is done with the patient completely asleep (under general anaesthesia). It is performed through the nose, using an endoscope, which is a special lighted tube that enables the surgeon to view the nose and sinus cavities as surgery is performed. There are no external cuts on the face. During surgery, blocked sinuses are opened with cutting instruments to facilitate drainage of the mucous from the sinuses. Quite often, a septoplasty (procedure to straighten the septum (bony-cartilaginous partition between the left and right nasal cavities)) may also be performed to allow access to the sinus cavities.



What are the possible risks and complications from FESS?


FESS in general is a safe procedure. As with all surgeries, there are some risks involved. The sinuses are close to the eyes and brain. Hence, injuries to these areas can theoretically occur during sinus surgery (but is rare). The risks of FESS can be divided into major and minor complications as follows:



Major complications (<1% risk) include:


1. Injuries to brain – Resulting in Cerebrospinal fluid (CSF) leak. This is a rare complication in which brain fluid leaks into the nasal cavity and may result in a brain infection (resulting in headache, neck stiffness, fever and sensitivity to light). Most CSF leak caused during sinus surgery can be repaired or heals spontaneously.


2. Injuries to eyes – This is rare and may result in double vision, blurred vision and in severe cases, loss of vision


3. Injuries to large blood vessels – This is very rare but may result in life-threatening bleeding



Minor complications include:


  1. Infection
  2. Scar bands in the sinuses
  3. Minor bleeding
  4. Recurrent infections
  5. Reduced or loss of sense of smell
  6. Bruising or swelling around the eyes
  7. Tearing of eyes
  8. Change in the quality of voice



Patients with nasal polyps have a higher risk of recurrence of the disease. However, an appropriate combination of FESS and long term medical treatment can reduce the risk of recurrence of polyps after surgery. Hence, it is important for such patients to be followed up regularly by their surgeon.


With the availability of image guidance system (IGS) during sinus surgery, the risks of major complications may be significantly reduced. Using IGS, the surgeon is able to confirm the position of the operating instruments in relation to critical structures such as the eye, brain or major blood vessels. This is particularly important in revision FESS (re-do sinus operation) whereby there may be a lot of scarring and distortion of important surgical landmarks from the previous surgery/ies or in cases where the sinus anatomy is complex.


*The risks and complications referred to in this form are not intended to be exhaustive. There may be uncommon risks of the procedure not referred to in this form, or those that are applicable to you specifically due to individual patient risk factors. Please ask your doctor for more information.



What is the recovery after FESS?


After sinus surgery, the surgeon will usually place dressings in the sinus cavities to prevent post-operative adhesions and to minimise bleeding. These dressings may be absorbable (which do not require removal) or non-absorbable (which will usually be removed between 5 – 10 days after surgery). In some conditions, “nasal packs” may be inserted in the nasal cavities to minimise bleeding after surgery. These “nasal packs” are non absorbable and are usually removed in 1 – 2 days. Depending on the extent of the sinus operation, the patient may be allowed to go home on the same day (as a Day Surgery Procedure) or may be admitted to the ward and observed overnight. It is common for patients to feel blocked in the nose from the packing material and blood clots. A nasal gauze (“bolster”) will be placed under the nose to collect any blood that drips out (Fig 2). This is usually removed before the patient goes home. There may be mild pain after the surgery but this is usually well-controlled with pain relievers.



Fess Figure



Patients are instructed to wash his / her nose with specially prepared salt solution (nasal irrigation or “douche”) 2 – 3 times a day. This is very important in keeping the sinuses clean and moist, thereby helping to speed up healing and recovery of sinus function. Nasal irrigation is continued for at least several weeks after surgery and patients will be advised on how long to continue on this by their surgeon.


In the first clinic visit (usually between 5 – 10 days after surgery), the packing materials will be removed (if non-absorbable) or suctioned out (if absorbable). The surgeon will clean up the sinus cavities with the aid of an endoscope and suction. Following this, most patients will feel much better. The patient should be able to return to work 1 – 2 weeks after sinus surgery. The full recovery of the sinuses may take up to 6-12 weeks although most patients will feel well enough to conduct their normal daily activities after 1 – 2 weeks.



Are there any food restrictions after FESS?


Once the anaesthetic medications have worn off, you should be able to resume a normal healthy diet. There is no evidence that any particular food will worsen your recovery or outcome of your surgery. However, it is advisable to avoid very hot and spicy food or take excessive alcohol, in the 1st week after surgery. The increased blood flow associated with facial flushing can theoretically increase the risk of bleeding from the incompletely-healed tissues of the nose and sinuses at this time.



When can I resume heavy physical activity?


The healing process of the nose and sinuses varies from person to person. It is generally advised that patients should avoid any heavy physical activity (e.g. weight lifting, intense aerobic exercises) and swimming for at least a month after the surgery.



Are there alternatives to FESS?


The alternative to FESS depends on the reasons (indications) for the surgery. Most commonly, FESS is recommended when medical treatment has failed or if the patient experiences frequent episodes of rhinosinusitis. If these were the reasons, the alternative to FESS would be continuation of medical treatment or observation. The patient should understand that once his or her condition reached the stage that surgery is recommended, it is unlikely that the patient’s symptoms will get very much better with medical treatment alone.


It is best that you discuss with your doctor on the alternatives to FESS that is specific to your condition.



Best wishes,


Dr Gan Eng Cern
ENT Specialist Singapore

    When Should You See an ENT Specialist in Singapore?

    • Any ear, nose or throat symptoms that you are troubled with or concerned about
    • Persistent blocked nose with mouth breathing or snoring

    Dr Gan Eng Cern

    Dr Gan Eng Cern is a distinguished ENT doctor with fellowship training. In addition to his clinical practice as an ear, nose and throat specialist in Singapore, Dr. Gan has contributed to the academic field as a Senior Clinical Lecturer at the Yong Loo Lin School of Medicine, National University of Singapore. He is recognised for his extensive research work, with numerous contributions to reputable international ENT journals. Dr Gan is also highly sought after as a speaker and has shared his surgical knowledge as a surgical dissection teacher at various prominent ENT conferences and courses.


    • 2020 – Reader’s Choice Gold Award for Best ENT Specialist (Expat Living Singapore)
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    • 2014 – 19th Yahya Cohen Memorial Lectureship (awarded by the College of Surgeons, Academy of Medicine Singapore for best scientific surgical paper)
    • 2012 – Human Manpower Development Award (Ministry of Health, Singapore)
    • 2007 – Singhealth Best Doctor Award


    • MBBS – Bachelor of Science, Bachelor of Medicine, Bachelor of Surgery (University of New South Wales, Sydney, Australia)
    • MRCS (Edin) – Member of the Royal College of Surgeons Edinburgh, United Kingdom
    • MMed (ORL) – Master of Medicine in ENT (National University of Singapore)
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