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Robots are able to reach deep into the throat through the mouth to perform surgery. Ng Wan Ching reports
 Mr Remy Tan was not the only one losing sleep because of his sleep apnoea. Almost every night, his wife would stay up all night to watch him, afraid that he would stop breathing for good. Even when she did not do so, Madam Azah Aziz knew she would not get a good night’s rest anyway. “Besides his snoring, which sounded like a broken-down orchestra, he would also thrash about in his sleep because he was not breathing properly. He would elbow me in the head or other parts of the body,” said the 46-year-old housewife. Over and over, she told her husband to see a doctor about his sleep apnoea, which affects 15 per cent of the population here. For these people, restful sleep is impossible because they wake up multiple times in the night when their airways become blocked repeatedly and they stop breathing. But Mr Tan resisted, mainly because he was terrified of doctors and needles. “Going to a hospital is taboo for me. I don’t like pain and I’m allergic to some painkillers,” said the 48-year-old taxi driver and father of four children aged 14 to 26. But he knew he had to get help, after a few minor accidents. A couple of times, he had nodded off while waiting at a traffic light and his foot had slid off the brake, causing his vehicle to bump into the car in front.
An overnight sleep study done early this year at Singapore General Hospital (SGH) showed he had 49 episodes of partial or complete airway obstruction in an hour, when the norm is fewer than five episodes per hour. He also had 334 episodes of oxygen desaturation (drop in oxygen level in the blood) during the night, reaching a low 66 per cent (the norm is more than 95 per cent) at one point. Sleep endoscopy, which involved inserting a flexible tube with an attached camera through his mouth to see the dynamic changes in the upper airway during sleep, showed that he had significant tongue base obstruction. This means a region deep in his throat became obstructed when his tongue muscle relaxed during sleep.
If Mr Tan had been diagnosed six months earlier, he would have had only two treatment options: sleeping with a mask attached to a machine that delivers continuous positive airway pressure (CPAP) to keep the airway open or invasive surgery on his jaw and throat to enlarge the airway. But luckily for him, SGH began offering transoral robotic surgery (Tors), a new minimally invasive technique using a robot-assisted surgical system, late last year to treat patients with sleep apnoea. The surgeon uses surgical instruments mounted on robotic arms, which are inserted through the mouth deep into the throat to remove excess tissue at the tongue base region, so no external cuts are made. This has made such operations far less radical and painful for patients like Mr Tan. The treatment of choice for sleep apnoea is the use of CPAP because it is non-invasive and can address all levels of obstruction, except obstructive tissue deep in the nose or throat, said Dr Toh Song Tar, a consultant at the sleep disorders unit and the sleep apnoea surgery service at the department of otolaryngology (ear, nose and throat) at SGH. But it requires the patients to put on a mask that is attached to a machine every single night.
More than six out of 10 are unable to put up with it for long, as it can be quite uncomfortable. If CPAP fails to solve the problem, surgery may be considered but some procedures can seem too radical to patients. For example, a procedure to remove tongue base obstruction involves several bony cuts to increase tension on the tongue and prevent it from falling back and blocking the airway. Its potential risks include injury to the teeth, teeth death requiring subsequent dental implants, bone infection and bleeding.
 Another operation, the maxillo-mandibular advancement to shift the upper and lower jaws forward, thereby enlarging the airway, has by far the best success rates. However, most Asian patients are unwilling to have their upper and lower jaws sawed and moved, said Dr Toh. The 3-D high-definition camera of the robotic system enhances the surgeon’s view and the flexibility of the surgical instruments allows him to move freely even in a surgical field deep in the mouth. So the surgeon can operate on hard-to-reach areas, such as removing obstructive tissue from the base of the tongue, without the need to saw open the jaw or make big cuts in the neck. Seven to eight in 10 patients with sleep apnoea would have tongue base obstruction. The robotic system can be used to reduce or remove obstructive tissue in the tongue base without causing problems in swallowing or changing the patient’s appearance by moving his jaws, noted Adjunct Assistant Professor Tay Hin Ngan, consultant at the department of otolaryngology at SGH. Dr Tay and Dr Toh operate together on sleep apnoea patients using the robotic system. Sleep endoscopy is needed to guide surgeons in deciding where to operate on, Dr Toh said.
SGH is the only centre here that routinely performs sleep endoscopy before undertaking sleep apnoea surgery, like in world-class sleep centres, he added. The use of Tors to treat sleep apnoea patients was first published in an international peer-reviewed scientific journal in March last year by an Italian surgeon, Professor Claudio Viccini. He learnt to use the robotic system from the University of Pennslyvania surgeons who developed it for throat cancer. Last July, one of the Tors pioneers from the University of Pennslyvania, Professor Bert O’Malley Jr, was invited to Singapore as a Ministry of Health expert in robotic surgery in ear, nose and throat. “He brought to our attention the potential use of the robotic system in treating sleep apnoea patients, which showed very favourable results in his centre as well,” said Dr Toh. Dr Tay said: “Our initial experience has been encouraging and I think that as we gain more experience, we can offer it routinely to more patients.”
So far, SGH has performed this procedure on six patients with obstructive sleep apnoea. One of them was Mr Tan, who chose robotic surgery over conventional surgery or the CPAP machine. He said: “The doctor said the surgeon could also make a hole in my jaw and pull forward the tongue muscle that is obstructing my breathing during sleep. I said no, no, no, give me the robot.” An SGH spokesman said patients pay about $6,000 to $8,000 more for transoral robotic surgery as compared to conventional surgery. Although it was costly, the operation, which took place early last month, was worth the money, Mr Tan said. He sleeps much better now. “Now, even if I sleep for just four hours, I feel refreshed and ready to go. No more falling asleep at the wheel,” he said. His wife is also happy not to have any more sleep-time drama. She joked: “I was so used to his broken-down orchestra. Now it’s so quiet when he sleeps, I wake up to check that he’s still breathing.”
Help for interrupted sleep
If you suffer from snoring and mild obstructive sleep apnoea:
- Reduce weight.
- Avoid alcohol or medication that aids sleep as these relax the muscles at the back of the throat and cause obstruction by blocking the airway.
- Sleep on one side or the stomach, instead of on the back, to prevent the tongue and soft palate (the back of the roof of the mouth) from collapsing against the back of the throat.
- Clear a blocked nose with medication recommended by a doctor or pharmacist.
- Use dental appliances that reposition the lower jaw and tongue during sleep.
If you suffer from moderate to severe sleep apnoea:
- Use a continuous positive airway pressure device to keep the airways open during sleep.
- Undergo surgery to enlarge the back of the throat.
What is sleep apnoea?
In all people, the throat and tongue muscles relax during sleep, narrowing the airway. However, in sleep apnoea patients, because their airways are smaller than normal to begin with, this narrowing can pose a problem, said Dr Toh Song Tar, a consultant at the sleep disorders unit and the sleep apnoea surgery service at the department of otolaryngology (ear, nose and throat) at Singapore General Hospital. The narrowing can be caused by the tongue falling back; excessive tissue at the back of the tongue; the throat wall tissues, the valve-like epiglottis that covers the opening to the throat and excessive mucosa around the voice box obstructing the entry to the windpipe. The obstruction can be complete or partial. Complete obstruction causes breathing to stop and can cause oxygen levels in the blood to drop dangerously low. “Because the body needs oxygen, the brain has to ‘wake’ up to allow the airway to open. This leads to sleep deprivation,” said Dr Toh.
So patients have excessive daytime sleepiness, cannot concentrate at work, are prone to road traffic and industrial accidents, and may suffer from depression and anxiety. The lack of oxygen means that the heart has to work much harder to send more blood and the oxygen available to the tissues. The lower oxygen level also induces a state of inflammation which is now being recognised as a significant cause of blood vessel damage, said Dr Toh.
If they do not get treatment, people with obstructive sleep apnoea are at higher risk of developing high blood pressure and coronary heart disease, suffering a heart attack and stroke, and dying earlier than normal individuals, he added. At least 15 per cent of people in Singapore are estimated to suffer from the condition. Men are at greater risk. The prevalence in women is lower. However, it rises after menopause. Some researchers think that female hormone oestrogen may have some protective effect. “But the how and why are still actively being researched,” said Dr Toh.
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