Functional Endoscopic Sinus Surgery (FESS) is a minimally invasive procedure used to treat certain conditions affecting the nose and sinuses, particularly chronic sinus disease that has not responded adequately to medical treatment.
Unlike traditional sinus surgery, FESS is performed through the nostrils using a small endoscope, allowing the surgeon to see and treat the affected sinus areas without making an external facial incision.
If you have been advised to undergo FESS, understanding what happens during the procedure can make the process easier to understand. The surgery is tailored to your sinus anatomy and the areas affected by disease, so the exact steps can differ from one person to another.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
For a broader overview of FESS and the conditions it may be used to treat, you can visit the Sinus Surgery (FESS) parent page.
What Happens Before FESS?
FESS begins with careful assessment and surgical planning rather than immediately proceeding to the operating room. Your ENT specialist reviews your symptoms, previous treatments, nasal examination and endoscopy findings, and imaging when appropriate.
A CT scan of the sinuses is commonly used when surgery is being planned. It provides detailed information about the sinus anatomy and helps the surgeon identify the areas affected by disease and plan the appropriate surgical approach. The goal is to determine which areas actually need treatment and avoid unnecessary removal of healthy tissue.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
How Is FESS Performed?
FESS is performed through the nasal passages. A thin endoscope with a light and camera is introduced through the nostril, allowing the surgeon to view the nasal cavity and sinus openings on a monitor.
Specialized instruments are then introduced through the nostril alongside the endoscope. The surgeon uses these instruments to treat the specific areas causing the sinus problem.
1. Anesthesia Is Given
FESS is commonly performed under general anesthesia, although the choice of anesthesia depends on the planned procedure and individual circumstances.
Once anesthesia has taken effect, you will not be awake or aware of the surgical procedure when general anesthesia is used.
2. The Endoscope Is Inserted Through the Nose
The surgeon carefully passes the endoscope through the nostril into the nasal cavity. The camera provides a magnified view of the structures inside the nose and the openings leading to the sinuses.
Because the surgical approach is through the natural nasal passages, FESS generally does not require an external incision on the face.
3. The Affected Sinus Areas Are Identified
The surgeon examines the areas affected by inflammation, obstruction, polyps, or other sinus disease. The preoperative CT scan and endoscopic findings help guide the procedure.
The sinuses are not all treated automatically. The extent of surgery depends on which sinuses are affected and the specific pattern of disease.
4. Obstructing or Diseased Tissue Is Removed
Small surgical instruments are used to remove tissue that is contributing to blockage or preventing normal sinus drainage.
Depending on the condition, this may include nasal polyps, inflamed tissue, or other obstructing material. The purpose is to treat the diseased areas while preserving healthy structures as much as possible.
5. Natural Sinus Openings Are Enlarged When Needed
Inflammation, polyps, and other changes can narrow or block the natural openings through which the sinuses drain. During FESS, the surgeon may carefully enlarge these openings to improve access, ventilation, and drainage.
The exact openings addressed depend on the sinuses involved. Surgery may therefore be limited to a small number of sinus compartments or involve several sinuses when disease is more extensive.
6. The Sinuses Are Cleared and the Surgical Area Is Checked
After the necessary tissue has been removed and the affected sinus pathways have been opened, the surgeon checks the treated areas using the endoscope.
The aim is to leave the sinus passages in a condition that allows them to drain more effectively and makes postoperative medical treatment easier to deliver.
Which Sinuses Can Be Treated During FESS?
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
The sinuses are air-filled spaces located around the nose and eyes. Depending on the disease pattern, FESS may involve one or more of the following:
- Maxillary sinuses: Located beneath the cheeks
- Ethmoid sinuses: Located between the eyes
- Frontal sinuses: Located above the eyes and forehead
- Sphenoid sinuses: Located deeper behind the nasal cavity
Does FESS Involve Cutting the Face?
Usually, no. FESS is performed through the nostrils using an endoscope and specialized instruments. Because the surgeon works through the nasal passages, there is generally no external facial incision.
This endoscopic approach allows the surgeon to directly visualize the relevant sinus structures while treating the areas responsible for the disease.
What Happens to Nasal Polyps During FESS?
If nasal polyps are contributing to the sinus disease, they may be removed during FESS. However, the procedure is not simply a matter of removing every visible polyp.
The surgeon also addresses the sinus pathways affected by the underlying disease. This can help improve sinus drainage and create better access for postoperative topical treatments.
Because nasal polyps are associated with chronic inflammation, removing them does not necessarily prevent them from returning. Long-term medical treatment may still be necessary after surgery.
What Is the Role of the Endoscope During Surgery?
The endoscope is central to FESS. It provides direct visualization of structures inside the nasal cavity and around the sinus openings that cannot be adequately seen from outside.
The surgeon can view the surgical field on a monitor while using small instruments through the nostril. This allows the procedure to be targeted to the areas that need treatment rather than relying on a larger external surgical approach.
How Long Does FESS Take?
The duration of FESS varies considerably. It depends on the number of sinuses being treated, the severity of disease, the presence of nasal polyps or other abnormalities, and whether additional procedures are being performed at the same time.
For this reason, there is no single operating time that applies to every FESS procedure. Your surgeon can give you a more specific estimate after reviewing your imaging and treatment plan.
What Happens Immediately After FESS?
After the procedure, you are taken to a recovery area where your condition is monitored as the effects of anesthesia wear off.
You may experience some nasal congestion, mild discomfort, drainage, or a feeling of pressure during the early recovery period. The exact postoperative experience varies according to the extent of surgery and individual healing.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Your doctor may recommend saline nasal irrigation and other topical treatments during recovery. Follow-up visits are also important because the nasal and sinus passages need to be monitored as they heal.
Why Is Follow-Up Important After FESS?
FESS is not necessarily the end of treatment for chronic sinus disease. The underlying inflammatory condition may continue even after obstructing tissue has been removed and sinus pathways have been opened.
Follow-up allows your ENT specialist to assess healing, manage inflammation, remove postoperative debris when necessary, and adjust medications according to your recovery.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
For patients with nasal polyps or chronic inflammatory sinus disease, ongoing medical treatment can be particularly important because surgery does not guarantee that the disease will never return.
Is FESS the Same for Every Patient?
No. One of the important features of functional endoscopic sinus surgery is that it is tailored to the individual patient's disease.
Two people may both be diagnosed with chronic sinusitis but require different procedures. One person may have disease affecting only one sinus, while another may have more extensive inflammation involving several sinuses and nasal polyps.
Your symptoms, endoscopic findings, CT scan, anatomy, previous treatment, and underlying condition all help determine the appropriate surgical approach.
The Bottom Line
Functional Endoscopic Sinus Surgery is performed through the nostrils using an endoscope and specialized instruments to treat diseased or obstructing tissue and improve the natural drainage pathways of the sinuses. The surgeon uses preoperative evaluation, endoscopic findings, and imaging to determine which areas require treatment.
Because FESS is tailored to the individual, the procedure can range from treatment of a limited number of sinus areas to more extensive surgery involving multiple sinuses. The goal is to improve sinus function while preserving healthy tissue as much as possible.
Recovery and long-term treatment also form an important part of the process. For chronic inflammatory sinus conditions, surgery may improve access for ongoing medical treatment rather than replacing medical management completely.
