SINGAPORE: In the pristine, sterile environment of a hospital ward, the last thing one might expect to find are maggots.
The wriggling, squirming creatures are typically associated with grim serial killer discoveries or rotting food.
But at National University Hospital (NUH), they have been used in the Department of Rehabilitation to treat chronic wounds with large amounts of dead or infected tissue.
Known as maggot debridement therapy, this procedure has been used to treat four NUH patients since August. The therapy will be performed on other suitable patients from early 2021.
Speaking to journalists at the hospital on Wednesday (Nov 11), podiatrist John Chen said the procedure is traditionally used as a "last resort" treatment for salvaging limbs, especially for patients who may be deemed "too high risk" to enter the operating theatre.
However, this has changed over time as doctors begin to understand more about how maggot debridement therapy works, he said.
Most of the patients who receive this therapy are older diabetic patients, but burn patients or those with autoimmune conditions may also be suitable, he added.
"Maggot debridement therapy is typically used for chronic wounds. Wounds that really have quite a bit of dead tissue. Chronic wounds tend to have a large proportion of necrotic tissue, which is non-living tissue, and basically this is a food source for the maggots," said Mr Chen.
"Maggot debridement therapy has shown some clinical benefits in reducing the colonisation of some antibiotic-resistant strains of bacteria at the wound bed and also promoting wound healing."
It should not be seen as a single treatment that will prevent an amputation, Mr Chen added, as extensive medical and surgical care is still critical.
The treatment costs between S$300 and S$1,100 depending on the size of the wound, the patient's response to the treatment and the number of dressing applications required, said the podiatrist. Elderly patients in the Pioneer generation are entitled to subsidies.
First, the wound is cleaned and prepared, and the surrounding skin and edge of the wound is also protected. This is important because maggots secrete enzymes that cause the wound to become "quite liquidised", and one can expect drainage from the wound, said the podiatrist.
The maggots, which are sterile, arrive in vials of about 200 squirming creatures. They are applied to the wound, and two layers of dressing are added.
"Basically because they're living creatures, they need oxygen and things like that to breathe. And they need an air passage, so the dressing is very important," said Mr Chen.
The maggots stay on the wound for about 48 to 72 hours, and this cycle repeats about three to five times, depending on the patient's progress, he added.
With hundreds of maggots wriggling and feeding on the dead tissue under the dressing, seeing them squirm their way out of the tissue and around your leg could be nightmare-inducing for some. Thankfully, they never get the chance to, said Mr Chen.
"The maggots, it's surprising, they don't actually tend to escape from the wound because all their food is actually on the wound bed. So they're attracted more to the wound bed than trying to escape to other areas," said the podiatrist, noting that the primary dressing also helps to seal the maggots in.
Maggot debridement therapy is "quite a safe treatment" and the risks are low. Some patients may bleed a bit and feel some discomfort, especially at night, as the maggots move around and feed on the dead tissue, he added.
"IT'S NOT THAT PAINFUL"
Mr William Teo, who has been warded for about one-and-a-half months, is one of four patients at NUH who has undergone the treatment. He had maggots living in a deep wound in his right heel for about one-and-a-half weeks, with his fifth and last cycle ending on Wednesday.
"At first I thought I would be frightened. When they put the maggots in, I didn't know whether there would be pain. But when they first put it (in), I feel like no pain at all," said the 58-year-old, who has been living with Type 2 diabetes for the past 28 years.
Mr Teo, who works in security, also has kidney problems and is currently undergoing dialysis.
"I feel they eat, they bite, just a bit of pain like an ant biting you. That's all, it's not that painful," he said, adding that there is some pain when the maggots try to eat the healthy tissue.
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It all began about two to three months ago when he visited the doctor at another hospital for an unrelated fever. During his four-day stay in the hospital, the doctor discovered a hole in his right heel and removed some of the flesh around it.
Shortly after he was discharged, Mr Teo went to NUH for a follow-up appointment for his kidney problems. The doctor also inspected the wound in his heel and decided that he had to be warded.
As the wound grew bigger with more and more dead tissue forming, the medical team introduced the idea of maggot debridement therapy to Mr Teo. He had never heard of it before.
"(I decided) I can try it. There's nothing to be afraid of. Just put it down and see how the maggots eat the dead flesh," he said.
After five cycles, all the dead and unhealthy tissue in Mr Teo's wound is gone. The plan, for now, is treatments that will allow healthy tissue to form and help the wound heal, said Mr Chen, who has been involved with Mr Teo's treatment from the start.
Comparing pictures of the wound before and after maggot debridement therapy and watching the dead tissue slowly disappear made Mr Teo feel "good".
"I see them eating, eating. The wound all become red colour. That means the good tissue all come out already, the bad tissue still have a bit. So they have to put in (more maggots), until the bad, brown tissue all gone. They just cleaned it up for me," said Mr Teo.
"Just now I took another photo and saw the wound. Wah, very nice."