14 Apr 2011
By: JOAN CHEW
Beginning early last year, a strange thing would happen to housewife Tan Geok Kee whenever she sat down to a meal.
As she ate, she would feel the area behind her right ear swell to the size of half an egg.
Said Madam Tan, 52, in Mandarin: "When I touched that area, it felt hard and there was a little pain. But as long as I didn't eat, the lump would become smaller."
In March that year, Madam Tan, who is a kidney patient, was diagnosed with sialolithiasis, a condition in which stones are formed within a salivary gland or duct.
The lack of glandular secretion as a result of dehydration from certain diseases increases the risk of such stones forming. One example of such a disease is Sjogren's syndrome which is an autoimmune disease that destroys a person's glands producing saliva and tears.
People with kidney disease, like Madam Tan, are also more susceptible to dehydration, which in turn increases their risk of getting sialolithiasis.
During mealtimes, when there is increased saliva production, the stones block the saliva from flowing out of the ducts and this causes the gland to swell and become painful.
For Madam Tan, it was the parotid gland, one of three major salivary glands located in and around the mouth and throat, that was blocked. The parotid glands on each side of the face lie in front of the ears or just behind the jawline.
New scarless procedure
Happily for her, National University Hospital (NUH) had introduced only one month before a new procedure to remove such stones without the need for surgery.
She is now one of only 17 patients at the hospital to have had a sialendoscopy, a minimally invasive technique which uses a basket attached to a scope to scoop out the stones from the salivary duct.
Unlike surgery, it leaves no scar on the patient's face, allows the patient to recover faster and is less risky.
Singapore General Hospital (SGH) is the only other public hospital which will be offering the procedure to its patients from next month.
Dr Ng Yuk Hui, associate consultant at the department of otolaryngology at SGH, said the 1.3mm rigid scope is inserted into the salivary duct to locate the stones.
In addition, a balloon attached to the scope is used to dilate abnormal strictures in the ducts which could also obstruct the flow of saliva.
Previously, patients like Madam Tan would have had surgery that would leave a 10 to 15cm scar stretching from ear to jaw, said Dr Loh Woei Shyang, senior consultant at the department of otolaryngology – head & neck surgery at NUH.
Sialendoscopy is done as a day surgery procedure under general anaesthesia.
Madam Tan was hospitalised for a day afterwards for observation as she was one of the first patients to try the procedure.
She told Mind Your Body she could eat normally two days afterwards.
In contrast, patients who went under the knife would need two to three weeks to make a full recovery, said Dr Loh.
Fewer complications
The new procedure also reduces the chances of complications associated with open surgery.
Dr Loh pointed out that open surgery sometimes damages the nerves that control the facial muscles.
He said: "The patient's face may become droopy, his smile non-symmetrical and his eyelids unable to close properly."
Fearing such disfigurement, doctors or patients may put off treatment.
Uppermost on patients' minds would be the cost of the new procedure, which Dr Loh puts at between $4,000 and $5,000, depending on the requirements of the surgery. This is half the cost of open surgery.
Dr Loh pointed out that overseas studies have estimated the incidence of symptomatic sialolithiasis to be around 27 to 50 new cases per million population per year.
This suggests there may be 100 to 200 such cases in Singapore per year, with NUH seeing about 30 a year.
Although not life-threatening, the condition may result in significant pain and discomfort and infections and bacteria can spread in the blood.
However, Dr Ng said not all patients would be suitable for sialendoscopy, which would depend on the size of the salivary duct.
Since the opening of the duct is much smaller than the size of the scope, the surgeon has to carefully dilate it first to make it large enough for the scope to enter.
He explained: "In some cases, there may be bleeding or swelling of the duct which does not make sialendoscopy possible."
Another challenge that crops up would be the size of the stone, he added.
He said: "If the stone is too large and stuck to the walls of the duct, we cannot get the basket past it and therefore we may not be able to remove such stones except through open surgery."
Email: joanchew@sph.com.sg
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