Patients have sense of smell restored thanks to surgery to treat long covid

Experts at UCLH used a technique for correcting blocked nasal passages on patients who have suffered a profound loss of smell after covid infection

Penelope Newman, who underwent surgery to restore her sense of smell because of long Covid (PA)

People in the UK who lost their sense of smell, and accompanying taste, because of long covid, have had it restored thanks to nasal surgery.

Experts at University College London Hospitals NHS Foundation Trust (UCLH) used a technique for correcting blocked nasal passages on patients who have suffered a profound loss of smell after covid infection.

One 27-year-old patient in the new UCLH study has had her sense of smell return almost to normal and is now expanding the range of foods she can eat.

All patients taking part in the research had an impaired sense of smell for longer than two years and had failed on other treatments, such as smell training and corticosteroids.

The food I could cook and eat was so limited, and I couldn't go out to restaurants as I would feel unwell

The operation, known as functional septorhinoplasty (fSRP), is typically used to correct any deviation of the nasal septum, increasing the size of nasal passageways.

This increases the airflow into the olfactory region, at the roof of the nasal cavity, which controls smell.

The team behind the new study said the surgery allows an increased amount of odorants (chemical compounds that have a smell) to reach the roof of the nose, where sense of smell is located.

They believe increasing the delivery of odorants to this area “kick starts” smell recovery in patients who have lost their sense of smell to long covid.

Penelope Newman, 27, from south London, took part in the trial. Her results have been published in the journal Facial Plastic Surgery.

I can now cook and eat garlic and onions and people can cook for me too. I can go out to eat with my friends and family

She said: “Before I had the surgery on my nose, I had begun to accept that I would probably never be able to smell or taste things the way I used to.

“It seemed dire, and after around two and a half years of parosmia (impaired sense of smell), I had totally changed my lifestyle.

“For those who have experienced this, they will know how isolating it can be.

“The food I could cook and eat was so limited, and I couldn’t go out to restaurants as I would feel unwell.

“Getting something as drastic as surgery was a risk I was willing to take on the small chance it might help.

“Since the surgery, I have begun to enjoy food and smells the same way I used to.

“I can now cook and eat garlic and onions and people can cook for me too. I can go out to eat with my friends and family.

If you're breathing normally through your nose, you can just feel the air moving in the lower part of the nose, and you probably don't even notice it, but when you sniff, you can feel the air going up into the olfactory area, the roof of the nose

“My taste and smell have almost returned to normal. I’m not sure if it will ever fully return as I still have a small reduction in it, but I am so glad that I am no longer as isolated as I once was.

“I will never take my senses for granted ever again.”

The new research was led by Professor Peter Andrews, senior consultant surgeon in rhinology and facial plastic surgery, and Alfonso Luca Pendolino, then senior rhinology fellow at UCLH.

It included 25 long covid patients, with 12 of the patients undergoing fSRP, while the control group of 13 patients continued with smell training – sniffing the same scents repeatedly – for the study.

Sense of smell was measured over the duration of the study by using the Sniffin’ Sticks test, a widely-used clinical test to detect smell.

All patients who had fSRP reported an improved sense of smell compared with none of the patients in the sniff test group, where 40% actually reported a worsening sense of smell.

It's the sort of forgotten group of people, to be honest

The experts said the surgery was particularly good at increasing odour sensitivity by lowering the odour threshold – the minimal concentration of an odour a person can actually smell – which is specifically noted in long covid patients with an impaired sense of smell.

Prof Andrews told the PA news agency that sense of smell “is bit like a muscle”, adding: “The more you use it, the stronger it is. Just like a muscle.”

He added: “If you’re breathing normally through your nose, you can just feel the air moving in the lower part of the nose, and you probably don’t even notice it, but when you sniff, you can feel the air going up into the olfactory area, the roof of the nose.

“What this operation does is it increases that airway.”

The surgery increases the airway by about 30%, so air flow also increases by about 30%.

Prof Andrews added: “There’s a big group of patients who are still suffering with this problem of smell dysfunction following covid infection three or four years ago.

“This study has shown impressive results – if we apply the principle of increasing the nasal or olfactory airway, we’re getting a reactivation of the sense of smell and then an improvement of the sense of smell.

“With long covid anosmia you’ve got patients, fundamentally, who can’t smell or smell very poorly, so we need to somehow wake them up.

“And this operation sort of does that. It sort of wakes up the olfactory mucosa  and then it builds on it through the increased nasal airway – hitting that area, more odorants hitting that area – and we’re getting this impressive recovery in the majority of the patients. All patients we operated on improved.”

Prof Andrews said persistent covid anosmia is still a problem for an estimated 50,000 to 100,000 people.

“It’s the sort of forgotten group of people, to be honest,” he said.

“If you lose your sense of smell it has incredible consequences. It’s not until you’ve lost your sense of smell (that you realise) how it affects your taste, how it affects your daily living.”

As a follow-up, researchers are now looking at the brain changes that happen following fSRP, which could explain its long-term benefits.