No. A deviated septum does not cause obstructive sleep apnoea, and any surgeon who tells you that straightening your septum will cure it is misleading you.
That is the short answer, and it disappoints people. The longer answer is more useful, because the nose genuinely does matter here, just not in the way most people assume.
Here is the distinction that carries the whole article. Obstructive sleep apnoea is a collapse of the throat during sleep. A deviated septum blocks the nose, which sits upstream of that collapse. Straightening the septum does not stop the throat closing. What it can do is worsen apnoea that already exists, and, far more importantly, it is one of the commonest reasons people cannot tolerate CPAP, the treatment that actually works. Fix the nose and the treatment often becomes usable. That is frequently worth more than people expect.
Where does obstructive sleep apnoea actually happen?
Obstructive sleep apnoea, usually shortened to OSA, is a collapse of the throat, not the nose. American sources spell it obstructive sleep apnea, and it is the same condition. During sleep the muscles holding the pharynx open relax. In susceptible people the soft palate, tongue base and pharyngeal walls fall inwards and close the airway, breathing stops for ten seconds or more, oxygen falls, and the brain briefly rouses you to restore muscle tone. Then it happens again. Often hundreds of times a night.
Your septum is nowhere near that. It sits well upstream of the site of collapse. Straightening it does not change the behaviour of the pharynx.
The things that genuinely drive obstructive sleep apnoea are body weight and neck circumference, jaw and facial structure, age, alcohol and sedatives, sleeping on your back, and enlarged tonsils, particularly in children and younger adults.
One more distinction worth making, because the terms get muddled. Central sleep apnoea is a different condition in which the brain intermittently stops sending the signal to breathe. The airway itself stays open, and nasal surgery has no role in treating it. Everything in this article is about the obstructive form, which is by far the more common.
What is a deviated septum, and why does it bend?
Worth a paragraph of anatomy, because plenty of people are told in passing that they have a deviated septum. The septum is the partition down the middle of the nose. It is made of cartilage at the front and bone at the back, and it splits the nasal cavity into two nasal passages, one on each side. When it sits in the midline, airflow is roughly even on the left and on the right. When it bends, one passage narrows and the other side is left doing most of the work.
There are two usual causes. Some deviations are developmental, where the cartilage and bone grow at slightly different rates through childhood and adolescence and the septum buckles under its own growth. The rest follow an injury, and the injury is often one nobody remembers, a knock in sport or a fall as a toddler rather than an obviously broken nose.
Almost everyone has some deviation. It only becomes a condition worth treating when it produces symptoms.
The symptoms that matter at night
The symptoms of a crooked septum are unglamorous and long-standing:
- Blockage that is clearly worse on one side
- Nasal congestion that swaps sides through the day, which is the normal nasal cycle (described by Kayser in 1895) exaggerated by a narrow starting point
- Difficulty breathing through the nose on exertion
- Chronic or recurrent sinus issues, because a deviated septum can crowd the drainage pathways of the sinuses
- A dry mouth and sore throat on waking, from a night of mouth breathing
- Nosebleeds from the dry, exposed convex side
Chronic rhinosinusitis is the one that gets missed, and it is the related condition I would most want to identify before blaming everything on the septum. If the deviation obstructs sinus drainage you can end up with persistent congestion, facial pressure and repeated courses of antibiotics that never quite settle it. Nasal polyps do the same thing on a larger scale. Either will make your nose difficult to breathe through at night, and either will wreck a nasal mask, so both need to be found and treated rather than assumed away. For the wider picture there is deviated septum symptoms, surgery and recovery.
So why does the nose matter at all?
Three reasons, and they are real.
Nasal resistance affects the pressure downstream. The upper airway behaves rather like a collapsible tube. Breathing in through a narrow nose generates a more strongly negative pressure further down, and that suction makes an already floppy pharynx more likely to collapse. A blocked nose does not create sleep apnoea, but it can worsen the events of someone who already has it.
Nasal blockage forces mouth breathing, which destabilises the airway. When your mouth falls open the jaw rotates back and down, taking the tongue base with it and narrowing the pharynx. Mouth breathing also bypasses the nasal reflexes that help maintain pharyngeal muscle tone. This is why people say their snoring is much worse when they have a cold.
And the big one: a blocked nose makes CPAP intolerable. This is where nasal surgery earns its place.
Why does a deviated septum make CPAP so difficult?
CPAP is the standard treatment for moderate and severe obstructive sleep apnoea. The full name is more useful than the acronym: continuous positive airway pressure. CPAP is a quiet pump that pushes air at a set pressure through a mask, and that pressure holds the collapsible part of the throat open from the inside. It is not oxygen and it is not a ventilator. It is a pneumatic splint, and it works extremely well when people use it.
The problem is that a great many people cannot. And one of the commonest reasons is a blocked nose. You cannot deliver pressure through a nasal mask into a nose that will not pass air. People end up switching to a full-face mask, which is bulkier and leaks more, or turning the pressure up until it is uncomfortable, or giving up entirely.
That is why the state of your nasal passages matters so much. A nasal mask has to move a real volume of air through them every breath, all night, and if one side is narrowed by the septum and the other is swollen, a treatment that works beautifully on paper becomes something you cannot sleep in.
Two practical points before anyone reaches for surgery. Modern CPAP machines include heated humidification, which reduces the nasal drying and congestion the airflow itself can cause, so make sure yours is set up properly. And a poorly fitting mask gets blamed on the nose more often than it should, so a session with your sleep service to refit the mask is never wasted.
This is where I can help, and it is honest to be specific about what improves. In people with genuine nasal obstruction, nasal surgery often improves CPAP tolerance and adherence, and can allow the required pressure to be reduced. It rarely cures the sleep apnoea itself, and the measured severity often barely changes.
That distinction matters. If you have moderate or severe sleep apnoea and cannot use CPAP because of your nose, fixing the nose is potentially transformative, not because it treats the apnoea but because it makes the treatment usable.
Do I need a sleep study before nasal surgery?
This is the part people most often get wrong, and it costs them time and money.
If you have any of the following, get a sleep study before you see a nose surgeon:
- Someone has witnessed you stopping breathing, gasping or choking in your sleep
- You wake unrefreshed regardless of how long you sleep
- You are sleepy during the day in a way that affects driving or concentration
- Morning headaches
- Loud snoring with pauses
Ask your GP. The test is usually a home sleep study, done in your own bed, and it produces a number called the AHI, the apnoea-hypopnoea index, the average number of breathing pauses per hour. An AHI below 5 is normal, 5 to 15 is classed as mild, 15 to 30 as moderate, and above 30 as severe. That number determines everything that follows: mild disease is often managed with weight, position and an oral appliance, whilst moderate and severe disease is where CPAP comes in.
Your GP or sleep clinic may also ask you to complete the Epworth Sleepiness Scale, a short questionnaire that scores how likely you are to doze in everyday situations. A raised score strengthens the case for a sleep study.
Coming to me first, having a septoplasty, and then discovering you still have severe sleep apnoea is a bad sequence. The nose is a contributing factor, not the diagnosis.
If the sleep study is normal and you simply snore and feel blocked, then nasal treatment on its own is a reasonable place to start.
Is snoring the same as sleep apnoea?
Plenty of people snore without having sleep apnoea. Snoring is vibration of the soft tissues. Apnoea is closure. They often travel together, but one does not prove the other, and treating snoring does nothing for untreated apnoea.
Improving the nasal airway often reduces snoring, sometimes substantially, because it stops you mouth breathing. It is a legitimate reason to treat the nose. It is not a treatment for sleep apnoea.
What does treating the nose actually change?
I would rather be specific about this than sell it, because the link between a deviated septum and sleep apnoea gets stretched hard in surgical marketing.
For the apnoea itself, nasal surgery is not the treatment, and it is a mistake to let anyone imply otherwise. Untreated moderate to severe apnoea is associated with cardiovascular disease, poorly controlled blood pressure and accidents caused by daytime sleepiness. None of that is fixed by a straighter septum. Weight, sleeping position, alcohol and consistent CPAP use are what change those risks.
For the nose, the evidence is better than most patients expect. The NAIROS trial, run across 17 NHS hospitals and published in 2024, found a large improvement in symptom scores and quality of life after septoplasty in patients with moderate to severe nasal obstruction, and little benefit in those whose symptoms were mild. Roughly 15 per cent still described a blocked nose at 12 months, which is an honest number to have before you decide.
So selection is everything. If your obstruction is genuine and significant, septoplasty is a well-established procedure with a good chance of improving your breathing, your sleep quality and your tolerance of a mask. If it is mild, it will probably not affect much, and I will tell you so rather than operate.
What are the options if CPAP is not working for you?
Work through the causes in order, because they have different fixes.
If the problem is the nose, that is my territory, and it is the commonest and most correctable reason. Sort out rhinitis medically, and deal surgically with a septal deviation or turbinate enlargement that medical treatment cannot shift.
If the nose is fine and CPAP still fails, there are established alternatives, and they belong with a sleep physician rather than a nose surgeon. A mandibular advancement device is a gum shield style appliance, made by a dentist, that holds the lower jaw forward during sleep, and it is an established option for mild to moderate obstructive sleep apnoea and for snoring. Some people have events mainly when lying on their back, and positional therapy, keeping off the back with a trainer device, reduces events in that group. Weight loss remains the intervention with the broadest effect. And for selected patients who genuinely cannot use CPAP, surgery to the palate or tongue base and hypoglossal nerve stimulation exist, but they need proper assessment by a sleep multidisciplinary team, not a decision made in a nasal clinic.
The wrong move is to abandon treatment quietly. Untreated apnoea does not go away because the mask was annoying.
Other things that block a nose, and what to try first
Several other conditions produce the same nasal symptoms and lead to the same mask problems. The ones I see most are allergic rhinitis, turbinate hypertrophy and nasal valve collapse. Even a perfectly straight septum can sit in a nose that shuts flat on the pillow. That is why the examination matters more than the diagnosis you arrive with.
Medical treatment first, saline irrigation and a steroid spray used properly, is often the right opening move, and it is something your GP or any doctor can start without sending you to me. Steer clear of decongestant sprays beyond about a week, because rebound congestion from rhinitis medicamentosa will make everything worse.
External nasal strips and internal nasal dilators are worth knowing about too. They splint the nasal valve open and can ease night-time blockage when the sidewalls of the nose collapse on breathing in, though they do nothing for the septum itself. If a strip transforms your breathing, that points at the valve rather than the septum, which is useful information to bring to a consultation. There is more on the non-surgical options in fixing a deviated septum without surgery.
What does septoplasty cost, and will insurance cover it?
Septoplasty for nasal obstruction is functional surgery, not cosmetic, and that changes the funding picture. Private medical insurers will often cover it when there is documented obstruction, subject to your policy terms, so it is always worth asking your insurer for pre-authorisation before assuming you must self-fund.
For self-paying patients, my septoplasty fees start from £6,000, and the procedure is BUPA fee-assured. Where the turbinates need reducing at the same time, which is common in this group, septoplasty with bilateral turbinate reduction starts from £7,100. A consultation is £250, credited towards surgery if you go ahead. Full details are on my pricing page.
If the outside of the nose is also crooked, or the septal deviation involves the part of the septum that supports the nasal tip, the operation needed may be a septorhinoplasty rather than a septoplasty alone. That is a bigger undertaking and a different conversation, and I will tell you plainly which one your nose needs.
What I would do at an assessment
In clinic I examine your nose with a camera, before and after a decongestant, to separate swelling from structure. I look at the tonsils, the palate and the tongue base, because those are the levels that matter for apnoea. And I ask about weight, alcohol, sleeping position, and whether you have had a sleep study.
If your nose is structurally blocked and you are struggling with CPAP, septoplasty, usually with turbinate reduction, is a well-founded intervention and I would recommend it. If your nose is essentially fine and your problem is a floppy pharynx, I will say so, and the honest advice is weight, position, alcohol and CPAP rather than an operation on your nose.
If you are not sure whether your septum is the issue at all, start with how to tell if you have a deviated septum. If the problem is mainly that your nose blocks the moment you lie down, blocked nose at night covers why.
Frequently asked questions
Can a deviated septum cause sleep apnoea?
No. It can worsen existing sleep apnoea and it commonly prevents people tolerating CPAP, but the obstruction in sleep apnoea occurs in the throat.
Will septoplasty cure my sleep apnoea?
Very unlikely on its own. It can improve CPAP tolerance and reduce the pressure needed, which is often the more valuable outcome.
Can a deviated septum cause snoring?
It can contribute, by forcing mouth breathing. Many people snore less after their nasal airway is improved.
Should I have a sleep study before nasal surgery?
If you have witnessed pauses, daytime sleepiness, morning headaches or loud snoring with pauses, yes. It changes the plan.
I cannot tolerate my CPAP mask. Can you help?
Often, yes, if the reason is nasal obstruction. That is one of the clearest indications for nasal surgery in this group.
Does a blocked nose alone cause daytime tiredness?
It can disturb sleep quality and leave you unrefreshed. Significant daytime sleepiness, though, should prompt a sleep study rather than being attributed to the nose.
Is sleep apnoea dangerous?
Untreated moderate to severe sleep apnoea is associated with raised cardiovascular risk and with accidents caused by sleepiness. It is worth diagnosing properly.
Can children have this?
Yes, and the usual cause is enlarged tonsils and adenoids rather than a septal deviation. That needs a paediatric ENT assessment.
Will losing weight help?
For sleep apnoea, frequently and substantially. It does nothing to a deviated septum, but it is often the single most effective intervention for the apnoea itself.
Can I have nasal surgery while using CPAP?
Yes. There is usually a short pause after surgery while the nose heals; the exact timing is agreed with your surgical team, and many people find the mask far easier afterwards.
If you are stuck between a nose that will not pass air and a CPAP machine you cannot use, that is a solvable problem and a common one. You can book a consultation. Bring your sleep study results if you have them.
If you would rather talk it through before committing to anything, call us on 020 7183 0220.
Mr David Whitehead is a Consultant ENT and Facial Plastic Surgeon in London, on the GMC Specialist Register for Otolaryngology and certified by the Royal College of Surgeons Intercollegiate Board in Cosmetic Surgery. More about my training and credentials.