Recovery Of Sense Of Smell After Nasal Polyps And Sinus Surgery - A Detailed Description

Introduction

Sense of smell is important, such as when sensing spoiled foods, smoke, or gas leaks. Olfactory (sense of smell) dysfunction is commonly due to sinonasal diseases such as nasal polyposis and chronic rhinosinusitis, traumatic injury, or viral injury. Nasal polyps are soft tissue growth on the lining of the nose and sinuses. Long-standing nasal polyps cause degenerative changes in the mucosa, which may cause impairment in the sense of smell, loss of sense of taste, runny nose, difficulty in breathing, postnasal drip, facial pain, and snoring. Sinus surgery is indicated in such cases, which has significant improvement in recovering the sense of smell, but the factors like age and gender do not affect the recovery of the sense of smell, hyposmic (partial loss of sense of smell) patients have no significant recovery, anosmic (complete loss of sense of smell) patients have remarkable improvement, and patients have good recovery in case of their first surgical treatment.

What Are Nasal Polyps?

Nasal polyps are soft tissue growths in teardrop shape on the lining of nasal passages and sinuses. They are painless and non-cancerous growths; large polyps may block the airway and cause breathing problems. Such nasal polyps require surgical treatment and are often associated with immune disorders, drug or other allergies, asthma, and recurrent infection. Nasal polyps are most common in middle age or young people. Left untreated, it can cause asthma flare-ups, sinus infections, and obstructive sleep apnea (a disorder where breathing is stopped for a few seconds during sleep).

What Are the Symptoms of Nasal Polyps?

Nasal polyps are associated with swelling of the nasal passage and sinusitis (inflammation of the sinus). Symptoms of nasal polyps are:

• Decreased or loss of sense of smell.

• Loss of sense of taste.

• Difficulty in breathing.

• Runny nose.

• Postnasal drip (accumulation of mucous at the back of the throat).

• Stuffiness.

• Headache.

• Facial pain.

• Pain near the upper molar teeth region.

• Nosebleeds.

• Snoring.

• A feeling of pressure on the face and forehead.

What Is Sinus Surgery?

Sinus surgery involves the removal of infected sinus tissue, polyps, or bone. The different types of sinus surgery are:

• Functional Endoscopic Sinus Surgery: This surgery involves the removal of infected tissue and trapped mucous by widening the nasal passage between the nose and sinus, with the help of an endoscope (thin tube with a camera and light), which uses an image-guided system.

• Balloon Sinuplasty: This surgery involves using a balloon to widen the nasal passage with the help of an endoscope and a catheter.

• Caldwell Luc Surgery: It is indicated when there is growth in the sinus cavity. In this surgery, an opening is made in the maxillary sinus through the second molar tooth region to drain mucous from the sinuses.

What Are the Indications of Sinus Surgery?

The indications of sinus surgery are:

• Sinusitis (inflammation of the mucosal lining of the sinus, which is hollow-filled spaces in the forehead, cheeks, nasal bones, and eyes).

• Recurrent acute rhinosinusitis (inflammation of the mucosal lining of nasal passages and sinus with sudden onset of four or more episodes per year, each lasting for at least ten days).

• Chronic rhinosinusitis (inflammation of the mucosal lining of nasal passages and sinus that lasts for at least twelve weeks) with or without nasal polyps.

• Sinonasal polyposis with airway obstruction.

• Fungal rhinosinusitis.

• Paranasal sinus opacification.

• Mucocele.

• Benign or malignant sinonasal tumors.

• Distorted anatomy of the nasal cavity and paranasal sinus.

• Skull base defects in case of cerebrospinal fluid leak.

What Is the Pathway of the Sense of Smell?

The smell stimulates the neuronal receptors of the olfactory epithelium, which is connected to the olfactory bulb by thin, non-myelinated nerve fibers. These neuronal receptors are located in the upper posterior part of the nasal septum, upper parts of the central and anterior cornea, and olfactory clefts, which triggers the neural cascade through the olfactory bulb, in turn, stimulate the olfactory cortex. Any alteration in this pathway will lead to loss of sense of smell. Major causes to alter this pathway are sinonasal diseases like nasal polyps and chronic rhinosinusitis, viral infections, and traumatic injuries. In the case of nasal polyps, because of airway obstruction, the air containing the smell receptors is blocked; another cause is microbial toxins that cause injury to the olfactory system. Removing the polyps and controlling the infection improves the sense of smell.

Can Nasal Polyps and Sinus Surgery Affect the Sense of Smell?

Loss of sense of smell is common in patients with nasal polyps and is usually because of obstruction in the airway, and chronic infections cause injury to the olfactory organ. Patients with long-standing polyposis have an impaired sense of smell. There may be irreversible impairment in the sense of smell due to degenerative inflammatory changes of nasal and sinus mucosa, recurrent infections, and many polyp operations that cause scarring. Postoperative steroid treatment improves the sense of smell by decongesting the nasal mucosa.

The recovery of the sense of smell after sinus surgery treatment depends on olfactory dysfunction disease duration, details on previous medications, involved sinuses, smoking, and other associated disorders like asthma. Therefore:

• Age and gender do not affect the recovery of the sense of smell.

• After endoscopic rhinosinus surgery, hyposmic (partial loss of sense of smell) patients have no significant recovery, but anosmic (complete loss of sense of smell) patients have remarkable improvement. Therefore patients with a higher score of olfactory dysfunction have a higher recovery rate.

• Patients who have undergone endoscopic sinus surgery for chronic rhinosinusitis also have good recovery in subjective and objective olfaction.

• Patients have a good recovery after their first surgical treatment.

Conclusion

Patients with chronic nasal polyps have degenerated epithelial mucosa, which results in an impaired sense of smell. Therefore, patients with rhinosinusitis who are treated with endoscopic surgery of the nose and sinuses have an improvement in the sense of smell to a greater extent, factors like age and gender do not affect the recovery of the sense of smell, hyposmic (partial loss of sense of smell) patients have no significant recovery, anosmic (complete loss of sense of smell) patients have remarkable improvement, and patients have good recovery in case of their first surgical treatment.