Treat sleep apnoea and get sound sleep


ROBOT-ASSISTED SURGERY: Dr Toh Song Tar (left) and Dr Tay Hin Ngan (middle) use a nasal scope to examine Mr Lee Kah Soon, who is suffering from obstructive sleep apnoea.

OBSTRUCTIVE sleep apnoea patients can rest easy with a new robot-assisted surgical procedure to remove obstructive tissue at the back of the throat.

He has begun to dream in his sleep again. It may not seem like much, but being able to dream means Mr Lee Kah Soon is starting to sleep normally again. For more than five years, the 45-year-old rarely slept well or deep enough for dreaming to occur. His sleep was disrupted so many times that, regardless of the number of hours he slept each night, he woke up the next morning feeling tired.

Mr Lee suffers from a disorder known as obstructive sleep apnoea – a condition where the upper airways are blocked repeatedly during sleep, causing the person to wake up many times. But undergoing a new robot-assisted surgery known as transoral robotic surgery, or TORS, to address obstruction deep in his throat has helped alleviate his symptoms.

“I wasn’t aware that I had this condition, although I snored and my family noticed I looked tired all the time. I didn’t think much of it and only went to see a doctor when I started having severe headaches and giddiness,” said Mr Lee.

Snoring a common symptom

The most common symptom of sleep apnoea is loud snoring, although patients also often experience excessive daytime sleepiness, forgetfulness, irritability and an inability to concentrate on work because of frequent disruptions to sleep during the night. Some patients have less obvious symptoms like early morning sore throat or headaches.

“As the condition worsens, the patient often stops breathing during sleep, gasping for air as a result of the airways closing,” said Dr Toh Song Tar, Consultant, Department of Otolaryngology (Ear, Nose and Throat Surgery) and Sleep Disorders Unit, Singapore General Hospital (SGH).

When the airways close or are blocked, oxygen levels in the blood can drop, sometimes to dangerous levels. However, sleep apnoea in itself is not a fatal condition because, when the brain senses the lack of oxygen, it wakes the patient from sleep and he begins breathing regularly again.

Obstruction of regular breathing can occur at different parts of the nose throat area – the nose, the palate (the roof of the mouth) or the base of the tongue. Mr Lee, like mostpatients with severe sleep apnoea, had obstruction in all three areas.

The airways close or get blocked for many reasons. In Asians, the typically smaller skeletal framework and structures in the throat play an important part in causing the sleep disorder. Children can get the disorder if they have overly large adenoids or tonsils, while the airways of adults often narrow as they put on weight or age.

Depending on where the obstructions are, the patient may be asked to make lifestyle changes such as losing weight or quitting smoking, or may have to use a mask-like device called Continuous Positive Airway Pressure (CPAP) to keep the airways open during sleep.

Patients can also have surgery to remove tissues in the nose or tonsils if the obstruction occurs in those areas, but a more invasive procedure is necessary if the problem lies further down the throat, such as at the base of the tongue.

For Mr Lee, the CPAP device was too uncomfortable to use. He also went through two earlier operations to open up his nasal passages and widen the area behind the palate.

However, he was reluctant to consider a third, more invasive operation, as he was wary of undergoing a procedure which involves cutting the jaw or chin bone in order to pull the tongue forward.

The base of the tongue is a difficult area to reach by conventional surgery and, unless a large incision is made, the surgeon’s view and access are blocked by the jaw and a large part of the tongue. Hence, this usually requires the jaw to be split open.

Robot-assisted surgical option

Luckily, for Mr Lee, a new minimally invasive technique using a robot-assisted surgical system for throat cancers became available late last year for treating sleep apnoea patients.

Robot-assisted surgery doesn’t require large incisions, or even incisions in some cases, to be made in procedures involving hard-to-reach areas. But it still allows surgeons to perform intricate procedures with a high degree of accuracy. This is because the surgeon performs the operation by manipulating surgical instruments mounted on robotic arms which have a range of movements wider than the human hands’. A 3-D high definition camera also gives the surgeon a clear view of parts of the body not easily seen except when the surgical area is cut wide open, as in conventional surgery.

In the new procedure to treat sleep apnoea, the surgical instruments are inserted through the mouth to perform the operation, so no external incision is made.

The robotic system’s camera enhances the surgeon’s view and the flexibility of the surgical instruments allows an unprecedented range of motion even in a surgical field so deep in.

“The (robot-assisted) system allows us to perform this procedure safely, allowing us to reach the most crucial part of the tongue base,” said Dr Tay Hin Ngan, Consultant, Department of Otolaryngology (Ear, Nose and Throat Surgery), SGH.

In November last year, Drs Toh and Tay performed the operation – the region’s first transoral robotic surgery for obstructive sleep apnoea – on Mr Lee. So far, the technique has been used on three other sleep apnoea and three throat cancer patients.

“There are those who chose not to address tongue base obstruction because they do not want bone surgery, but they can now have this option of a less invasive, safer method of surgery,” said Dr Tay, who regularly performs robot-assisted surgery on the thyroid, and head and neck tumours.

Robot-assisted surgery involving small incisions has several advantages over conventional open surgery for patients, such as a shorter time under anaesthesia, which reduces risk in any procedure especially for older people; less bleeding because of the smaller incisions; and often a shorter hospital stay and recovery period. However, the costs can be substantially higher.

For Mr Lee, it has made the difference from having airway blockages 46 times an hour to just eight. “I feel much better and fresher, and my mind is able to focus better,” said Mr  Lee.

About 15 per cent of Singapore’s population has obstructive sleep apnoea. This compares with 15 to 20 per cent for Asians in general and about 25 per cent in Koreans. While the smaller body skeletal structure among Asians tends to be the cause of the disorder, obesity is the main cause for Caucasians.

Patients tend to be males in their 30s or 40s, and the incidence tends to rise in women after menopause.

Not all snorers suffer from sleep apnoea, but patients with sleep apnoea all snore.

Soft, rhythmic snoring is usually harmless. But if the snoring becomes loud and changes in intensity, it may be indicative of obstructive sleep apnoea.

Severity gauge

The apnoea-hypopnea index (AHI) measures the number of complete airway blockages (apnoea) and partial obstructions (hypopnea) that occur every hour during sleep. An AHI of 5-15 is considered mild, 15-30 is moderate, and a value greater than 30 is deemed severe.

Ideally, blood should have at least 95 per cent oxygen. A little dip below that mark is still acceptable, but anything less than 90 per cent is not healthy.

Cure rates

When the AHI is less than five, patients are considered cured. In very severe cases, surgery that reduces AHI to less than 20 is deemed successful.

Getting uninterrupted sleep

To help 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

• Sleep on one side or on the stomach, instead of facing up, to prevent the tongue

and soft palate 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

For moderate to severe sleep apnoea

• Use a CPAP device to keep the airways open during sleep

• Undergo surgery to enlarge the back of the throat

This story was first published in Singapore Health, Mar/Apr 2012.