WASHINGTON, Aug. 26 - The medical use of maggots and leeches,
which has a centuries-old history, started on a post-antibiotics
comeback a generation ago. Now maggots and leeches, in their
roles of chewing dead flesh and eating blood, are becoming
so popular the FDA is taking a look.
Medical-grade maggots are used to debride necrotic flesh in
wounds such as neuropathic foot ulcers, pressure sores, and
venous stasis ulcers. They also disinfect the wound and stimulate
healing.
Medical leeches are used in microsurgical re-attachment of
body parts. Often the surgeon can rejoin arteries, but not
veins, so that blood entering the re-attached part can't escape
and can become stagnant. Leeches feed on the stagnant blood
until the veins can rejoin themselves.
"I think the agency is concerned (about the creatures) because
their use is growing," said Ron Sherman, M.D., of the University
of California at Irvine. Dr. Sherman has been growing and
distributing medical-grade maggots to physicians throughout
the U.S. for more than 10 years.
Demand for his maggots has been growing at between 25% and
50% a year over that time, said Dr. Sherman.
As the demand grows, Dr. Sherman said, it is likely that other
players will enter the marketplace, so "the FDA has good reason
to formalize things."
Oddly, even though leeches and maggots are living creatures,
it's the FDA's device division - responsible for such things
as stents and pacemakers - that is undertaking the review.
The agency decided that maggots and leeches are devices, mainly
because of how they perform their medical chores. Maggots
chew dead flesh and leeches eat blood. "Those are mechanical
processes," Mark Melkerson, acting director of the FDA's Division
of General, Restorative and Neurological Devices, told reporters.
Currently, both leeches and maggots are regulated as unclassified
devices. The agency is proposing that both maggots and leeches
be classified as class II medical devices, subject to some
safety requirements, but not as stringently regulated as class
III devices, such as implantable pacemakers.
One requirement, already in place, is that both maggots and
leeches be what is called "germ-free," Dr. Sherman said. "They're
living creatures," he said, "so they can't be sterile."
Medicinal maggots are the larvae of the green blowfly, or
Phaenicia sericata; medicinal leeches are freshwater annelid
worms of the species Hirudo medicinalis.
Leeches have been used for centuries, but not to help save
re-attached fingers - they were a staple of the medieval practice
of letting blood, thought then to have beneficial effects.
Maggots too have a respectable history, dating back at least
to the Napoleonic wars, when surgeons noticed that wounds
infested with maggots tended to heal better than others.
Perhaps the first doctor to use maggots intentionally was
Confederate surgeon in the Civil War, one J. Zacharias, who
wrote: "During my service in the hospital in Danville, Virginia,
I first used maggots to remove the decayed tissue in hospital
gangrene .... In a single day (they) would clean a wound much
better than any agents we had at our command."
"I am sure I saved many lives by their use," Dr. Zacharias
said.
The modern champion of maggots was William Baer, M.D., of
Johns Hopkins, who had observed their value on the battlefields
of World War I. Dr. Baer described two soldiers who had been
left wounded on the battlefield for days; when they got to
hospital, their wounds were found to be filled with thousands
of maggots.
But when the maggots were removed Dr. Baer found the wounds
were healing.
They went out of fashion after the advent of antibiotics,
but Dr. Sherman says they have immense value in many cases
where drugs are of no value, such as diabetic foot ulcers.
In 40 to 50% of cases where a limb is destined for amputation
because of such ulcers, he said, maggots have been able to
heal the wound.
"You hear a lot about the yuck factor," he said. "Let me tell
you it's simply not true if you talk to people with a draining,
stinking, life-threatening wound."
