Functional Endoscopic Sinus Surgery: Everything You Need to Know

Functional endoscopic sinus surgery (FESS), also known simply as endoscopic sinus surgery, is a minimally invasive procedure used to clear blockages in the sinuses and make breathing easier. The surgery may be necessary for people with recurrent sinusitis (sinus infection), sinus deformity, or abnormal growths in the sinuses for whom non-surgical treatments have failed.

FESS can be also be used to remove foreign objects from the sinuses, treat injuries to the optic nerve or eye socket, or unblock tear ducts.

What Is Functional Endoscopic Sinus Surgery?

Functional endoscopic sinus surgery is a form of surgery that uses a flexible endoscope to view inside the sinus cavities without opening the skin. The endoscope contains a tiny camera that transmits live images to a video monitor, the visuals of which help direct the placement of surgical instruments by the surgeon.

The sinuses are an interconnected system of hollow cavities in the skull comprised of the:

  • Maxillary sinuses in the cheeks
  • Ethmoid sinuses between the eyes
  • Splenoid sinuses between the eyebrows and upper bridge of the nose
  • Frontal sinuses in the forehead

FESS may involve one or more of these, depending on the concern being addressed.

FESS can be used on both children and adults. It is most commonly performed using local anesthesia, often with the addition of an intravenous sedative.


FESS can be extremely effective in treating refractory (treatment-resistant) sinusitis, but there are instances where the procedure may be inappropriate.

FESS is generally contraindicated in people with the following two conditions:

  • Orbital abscess: A serious infection of the eye socket resulting in a pocket of pus and fluids
  • Pott's puffy tumor: A rare abscess caused by a type of bone infection called osteomyelitis

For conditions like these, open surgery may be more appropriate.

FESS should be also be used with caution in people with serious bleeding disorders, such as hemophilia.

Potential Risks

While effective in many cases, sinus surgery does pose certain risks and requires a prolonged period of recovery.

In addition to the general risk of surgery and anesthesia, FESS may on rare occasion lead to the following post-operative complications:

  • Severe nasal bleeding that may require the termination of the surgery and, in some cases, hospitalization
  • Cerebral spinal fluid leak, which can occur if the ethmoid sinus in the center of the face is accidentally ruptured
  • Septal perforation, the accidental rupture of the cartilage separating the nostrils
  • Vision loss caused by injury to the optic nerve
  • Double vision caused by injury to the optic nerve or the eye itself
  • Permanent loss of smell or taste (mild to severe)

Purpose of Sinus Surgery

There are a variety of conditions that impair the flow of air through the sinuses, including allergies, sinus infections, structural deformities, and abnormal tissue masses. FESS is indicated when conservative treatments fail to provide relief of a sinus condition that is diminishing a person's quality of life.

More specifically, FESS can be used to treat the following conditions or perform the following procedures:

Pre-Operative Evaluation

If sinus surgery is indicated, the doctor may perform pre-operative tests to map out the surgical plan. Imaging is especially important as the sinus cavities are situated close to the eyes, brain, and several major arteries. Imaging allows the surgeon to map these structures in order to avoid them during the procedure.

Pre-operative tests may include:

A physical exam and review of your medical history may also be needed to ensure that you are candidate for surgery and anesthesia.

How to Prepare

If endoscopic sinus surgery is indicated, you will meet in advance with an ear, nose, and throat specialist known as an otolaryngologist who is qualified to perform the procedure. The doctor will review pre-operative results with you and discuss the surgery in detail, including what you need to do before and after.


FESS is typically performed as an outpatient procedure in a hospital or specialized surgical center. The operating room will be equipped with standard equipment used for surgery, including an electrocardiogram (ECG) machine to monitor your heart rate, a pulse oximeter to monitor your blood oxygen, and a mechanical ventilator to deliver supplemental oxygen if needed.

Nasal endoscopic surgery is performed with either a flexible or rigid endoscope connected to a live-feed video monitor. There are also specially designed surgical tools able to circumnavigate the sinus passages, including knives, forceps, retractors, and electrocautery devices.

What to Wear

You will need to change into a hospital gown for endoscopic sinus surgery, so wear something you are able to get into and out of easily. Avoid bringing any valuables with you, including jewelry and watches.

Also, be advised that you will need to remove contacts, dentures, hearing aids, and any mouth or nose piercings before surgery.

Food and Drink

FESS is typically performed with monitored anesthesia care (MAC), a form of intravenous sedation that relaxes you and induces "twilight sleep."

Because of this, you need to take the same dietary precautions as with any other type of anesthesia. That is, you will need to stop eating at midnight the night before the surgery. The next morning, you can take any medications approved by your doctor with a few sips of water. Within four hours of the surgery, nothing should be taken by mouth, including food, water, gum, or breath mints.


The doctor will advise you to temporarily stop using certain medications that promote bleeding. This is especially important with sinus surgery as the passages are lined with hundreds of capillaries that are vulnerable to rupture.

Medications like anticoagulants (blood thinners) and nonsteroidal anti-inflammatory drugs (NSAIDs) can impair blood clotting and lead to excessive and sometimes severe bleeding. Among the medications you may need to stop before and after endoscopic sinus surgery are:

NSAIDs and anticoagulants are typically stopped five days before and after FESS. Aspirin generally needs to be stopped 10 days before the surgery and up to two weeks after.

What to Bring

On the day of your surgery, you will need to bring ID (such as a driver's license), your insurance card, and a form of payment if copay or coinsurance costs are required upfront.

You will also need to bring someone with you to drive you home. Even if only local anesthesia is used, you will likely experience pain, discomfort, tearing, and blurring after the procedure. These can impair your ability to drive safely.

Other Preparations

Your otolaryngologist will advise you to buy a nasal spray decongestant that contains oxymetazoline, such as Afrin. This is to be used on the day of the surgery to help shrink tissues in the nasal passages.

If your sinus condition is related to allergic rhinitis (hay fever), you may also be advised to take an oral antihistamine to reduce tissue swelling. Similarly, if you are prone to recurrent sinus infections, a short course of oral antibiotics may be prescribed to reduce the risk of post-operative infection.

You will also be advised to stop smoking prior to and after sinus surgery. Not only does smoking exacerbate sinus problems, but it impairs healing by shrinking blood vessels and reducing the amount of oxygen that reaches the surgical wound.

Do not hesitate to ask your doctor for a prescription for smoking cessation aids that can help you overcome nicotine cravings. Aids like these are classified as Essential Health Benefits (EHBs) under the Affordable Care Act and may be fully covered by insurance.

What to Expect on the Day of Surgery

On the morning of your surgery, shower thoroughly but avoid putting any lotion, moisturizer, or makeup on your face.

An hour or two before the surgery, you will need to spray your nasal spray in each nostril as per the instructions on the product label. Each dose lasts for around 12 hours.

Once you are checked-in to the hospital or surgical center and have signed the consent forms, you are led to the back to undress and change into a hospital gown.

Before the Surgery

After you have changed, the nurse will take your height, weight, temperature, blood pressure, and heart rate. Your height and weight are important as they help calculate the correct dose of the sedative used for MAC.

You are placed on the operating table in a supine (upward-facing) position with your head tilted slightly back with a neck bolster.

In most cases, MAC will be used. This requires the placement of an intravenous (IV) line into a vein in your arm to not only deliver sedation but also pre-operative antibiotics that reduce the risk of infection.

To complete the preparations, adhesive electrodes are placed on your chest to connect to the ECG machine, while a pulse oximeter is clamped to a finger to monitor your blood oxygen saturation.

During the Surgery

Once the IV sedation has been delivered, the inside of your nostril is injected with a solution comprised of lidocaine (to numb the nasal passages) and epinephrine (to relax and widen the sinus cavities).

The endoscope is then fed into the nostril and sinus cavity, guided by live images on the video monitor. Depending on the aim of the surgery, tissues may be resected (removed), curetted (scraped), or cauterized (burned) to widen the sinus cavity or repair damaged structures.

If a polyp or tumor is resected, it is typically sent to a pathology lab to ascertain if there is any evidence of cancer. In some cases, bone or skin grafts will be used to fill in gaps caused by the removal of masses.

Upon the completion of the surgery, the treated site is packed with a dissolvable patch infused with antibiotics and/or oxymetazoline. A dissolvable spacer may also be placed within the passage to keep it open in the intended shape as you heal.

External nasal tubes or splints may also be placed along with cotton wadding to absorb any blood.

Depending on the complexity of the obstruction, endoscopic sinus surgery can take anywhere from one to four hours to perform.

After the Surgery

After surgery, you are wheeled into a recovery room and monitored for an hour or two to ensure that you are not experiencing excessive pain or bleeding and that you are able to eat and drink.

The nurse will continue to monitor your vital signs until they are normalized and you are steady enough to change into your clothes. A friend or family member can then take you home.

If you feel nauseous from the sedation, let the nurse or doctor know so that an anti-emetic drug can be prescribed. The doctor may also prescribe pain medication if needed.


Overview of Sinus Surgery
 Verywell / Madelyn Goodnight

Your doctor will provide you with detailed instructions on how to take care of yourself at home. Even so, someone should stay with you for at least 24 hours to help you out and monitor for any adverse symptoms.

To reduce pain and inflammation, keep your body in an upright position for the first couple of days. When sleeping, bolster yourself with two or three pillows.

You can expect to see some blood during this early healing phase, but the bleeding will usually stop within 24 to 72 hours. There may also be signs of bruising (usually mild) and eye redness.

Depending on the procedure used, your doctor may recommend over-the-counter Tylenol (acetaminophen) to help manage pain or prescribe an opioid painkiller like Percocet (oxycodone plus acetaminophen) for no more than three to five days.

You can also alleviate pain and inflammation by placing a cold compress atop the treated area for no more than 10 to 15 minutes, several times a day.


In most cases, people who undergo FESS can return to normal activity within one to two weeks. A full recovery with the complete resolution of symptoms may take between one to six months, depending on the procedure.

By adhering to your doctor's care instructions and following a few simple tips, you can ensure a faster recovery and reduce the risks of complications.

  • Protect your nose: Do not blow your nose for one week after surgery. Do not clean your nose with swabs or remove any packing, splints, or tubes until your doctor tells you to.
  • Use a saline nasal rinse: Once the external packing and tubes are removed, irrigate your sinuses twice daily with a commercial saline rinse kit recommended by your doctor. Many saline rinses come in a pre-filled squirt bottle, but you can also use a neti pot with sterile saline solution purchased at the drugstore.
  • Treat a nosebleed: If a nosebleed occurs, tilt your head back and breathe gently through your nose until it stops. A decongestant nasal spray like Afrin can also help stop nosebleeds, but avoid using it for more than three days as it can lead to rebound congestion.
  • Avoid other nasal sprays and use of CPAP: In addition to NSAIDs and anticoagulants, you should also avoid steroid nasal sprays and antihistamine sprays until your doctor gives you the OK. The same applies to continuous positive airway pressure (CPAP) machines used to treat sleep apnea.
  • Use a humidifier: Many surgeons recommend a cool-mist humidifier after sinus surgery to help keep the mucosal tissues moist as they heal. This is particularly helpful in arid environments or when using an air conditioner (which can draw moisture out of the air).
  • Check your nasal discharge: If you see brown discharge from your nostril, do not worry. This is dried blood mixed with nasal mucus. A thick, whitish or yellow nasal discharge is also common and more likely to be mucus than pus. Discharge only becomes concerning when accompanied by symptoms of infection.

When to Call a Doctor

Call your doctor if you experience any of the following after endoscopic sinus surgery:

  • Excessive nasal bleeding you cannot control
  • Increase pain, redness, and swelling around the surgical site
  • High fever (over 100.5 degrees F) with chills
  • Greenish-yellow discharge from the nose, particularly if it is foul-smelling
  • Changes in vision

Follow-Up Care

Your surgeon will want to see you a week or two after your surgery to make sure that you are healing properly. After a period of a month or two, another appointment may be scheduled to assess your response to treatment.

This follow-up appointment may involve a CT scan to compare to the initial studies. A repeat olfactory test may also be performed to check for any loss of smell.

Always let the doctor know about any symptoms you experience, however minor or insignificant you may think they are.

While 80% to 90% of people who undergo FESS for chronic sinusitis experience complete relief, there are some who may require additional treatment (including revision surgery).

A Word From Verywell

A functional endoscopic sinus surgery can be extremely effective in certain cases, but it is only indicated when all other options have been exhausted. Before moving ahead with a procedure, ask your otolaryngologist if other options for your condition are available, such as balloon sinuplasty—a newer technique in which a flexible bladder is inflated in the nose to enlarge the sinus cavity.

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