Endoscopic Nasosinusal Surgery: Minimally Invasive Surgical Technique

Functional endoscopic nasosinus surgery (FENS) is a minimally invasive technique used for the surgical treatment of the nose, paranasal sinuses and skull base.

The term “functional” was introduced to distinguish this type of endoscopic surgery from “conventional” non-endoscopic procedures. It is used for:

  • Endoscopic treatment of infectious and inflammatory diseases of the sinuses, restoring normal sinus ventilation and function.
  • Perform endoscopic septoplasty in some cases of mild to moderate severity.
  • Treatment of epistaxis (nosebleeds), avoiding in many cases repetitive tamponades and treatment of lacrimal duct diseases.
  • Treatment of pituitary adenomas.
  • Treatment of benign and malignant tumors of the anterior and middle skull base.
  • Its most frequent use is in patients with acute or chronic recurrent infectious sinusitis, in whom pharmacological medical treatment has failed, achieving positive results in 90 percent of the cases.

Fiber optic endoscopes have revolutionized the exploration and surgical treatment of these diseases. The use of computed axial tomography (CT) and navigation systems allows the anatomy to be evaluated and diseased areas to be identified, and more precise surgery to be performed. The procedure can be performed under general or local anesthesia on an outpatient basis.

CENS is a minimally invasive technique in which the air cells and sinus ostia are opened under direct visualization. The objective of this procedure is to restore mucociliary drainage of the sinuses by ventilation through the sinus ostium by a mucociliary transport mechanism that maintains a continuous protective layer of mucus leaving the sinuses.


Candidate selection involves a thorough history and physical examination before and after oral and local pharmacologic treatment. If the patient does not respond adequately to this, a CT scan should be performed to decide the type of surgery appropriate for each case.

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Postoperative care

In the postoperative follow-up it is important to keep the nose as free as possible of crusts. The techniques used to achieve this combine cleaning at the doctor’s office by the physician and nasal lavage with saline at home by the patient himself.

Normal function of the nasosinusal mucosa usually recovers in about two months. In patients with severe inflammation or polyps, a short course of oral steroids combined with antibiotics may speed postoperative recovery.


Outcomes after CENS are good, with most studies reporting a success rate of 80 to 90 percent. The procedure is considered a success if most symptoms resolve. Nasal obstruction and facial pain will most likely be relieved, although postnasal drip often persists. Recurrent acute infections should disappear. Regarding the recovery of the sense of smell, it depends on the degree of deterioration of the olfactory mucosa, so it does not always occur.


Among the important complications, cerebrospinal fluid leakage is the most common occurring in approximately 0.2 percent of cases. The leak is usually recognized at the time of surgery and can be easily repaired; it should be suspected if there is a clear nasal discharge postoperatively.

Other, less serious, but still rare, complications include orbital hematoma and nasolacrimal duct stenosis. It should be noted that all of these complications can also occur with “conventional” sinus surgery.

Functional endoscopic sinus surgery is a very safe surgical technique. Nowadays there are sufficiently safe therapeutic means that the possibility of complications is minimal. Endoscopic nasosinusal surgery is usually performed under general anesthesia, although there will be cases with complex pathologies in which local anesthesia and sedation will be necessary.