From Medscape General Surgery
Alternative Treatments for Wounds: Leeches, Maggots, and Bees
Karen M. Dente, MA, MD
The recalcitrant nature and complexity of chronic wounds continue to
challenge health practitioners in the field, with many of the standard
treatment options often failing to provide good outcomes. Chronic wounds
are often infected with bacteria resistant to antibiotics, compounding the
problem. Some alternative biologic forms of treatment have been used and
are gaining recognition; they include apitherapy (application of honey),
maggots, and leeches. In addition to other wound-promoting actions, they
all seem to show efficacy against bacteria, such as methicillin-resistant
Staphylococcus aureus (MRSA).
Honey -- A Topical Treatment for Wounds
In recent years, there has been a resurgent interest in the use of honey in
wound care. Honey, a plant nectar that is modified by the honey bee Apis
mellifera, has been used as a treatment for wounds since antiquity, with
records of its use dating back to the early Egyptians, Assyrians, Chinese,
Greeks, and Romans.
There are several mechanisms through which honey is thought to act on and
heal wounds. When it is applied directly on a wound surface or via a
dressing, it can act as a sealant, keeping the wound moist and free from
contamination. In addition, honey is comprised of glucose (35%), fructose
(40%), sucrose (5%), and water (20%). This high sugar content plus
vitamins, minerals, and amino acids) provides topical nutrition that is
thought to promote healing and tissue growth. Honey is also a hyperosmotic
agent that draws fluid from the wound bed and underlying circulation, which
kills bacteria that cannot thrive in such an environment. It is
bactericidal in other ways as well. During the process of honey production,
worker bees add the enzyme glucose oxidase to the nectar. When honey is
applied to the wound, this enzyme comes into contact with oxygen in the
air, which leads to the production of the bactericide hydrogen peroxide.
Macroscopically, honey has also shown debriding action.[1-3]
Manuka (Medihoney) is a medicinal honey with enhanced antibacterial
properties derived from floral sources in Australia and New Zealand. In
June and July 2007, Health Canada and the US Food and Drug Administration
(FDA), respectively, cleared it as the first medicinal honey product for
use in wounds and burns. Peter Molan, a New Zealand biochemist at the
University of Waikato, has reported that it can stop bacterial growth even
when diluted up to 56 times. He has conducted studies on this honey in rats
and piglets that have suggested that it has anti-inflammatory properties
and can stimulate epithelial growth, advancing closure of skin in these
"In the last few years, a lot of good science has been done in the area,"
said Shona Blair, a microbiologist at the University of Sydney, Australia
in an interview. She has tested various strains of honeys against bacterial
strains obtained from hospitals and found that even the strains most
resistant to antibiotics failed to grow in the presence of honey. Manuka
honey may even be active against MRSA.[5,6]
A review of the literature suggests positive results for honey in wound
care, but more confirming evidence is needed. About 17 randomized
controlled trials involving a total of 1965 participants have been
published; 5 other types of clinical trials involving 97 participants
treated with honey have also been reported in the literature. Furthermore
there are about 16 trials of honey on a total of 533 wounds in animal
models (which rule out a placebo effect). There are over 270 cases, of
mostly chronic wounds cited in the literature that were treated with honey.
Honey gave good results in all but 14 of these cases.[7,8]
For example, Dr. Jennifer Eddy, associate professor of family medicine at
the University of Wisconsin, provided a case study of a patient with a
severely gangrenous diabetic foot ulcer that was salvaged following honey
treatment. Dr. Eddy is currently recruiting patients with diabetic foot
ulcers for a study that will compare honey with hydrogel dressings that
appear like honey, having been altered to resemble honey in terms of
coloring and smell to maintain objectivity. Not all case studies have been
An observational study at the University of Bonn, Germany, reported good
healing rates in the use of honey as a dressing for wounds in 15 children
with cancer, who are prone to weakened immunity and poor wound healing
following radiation treatment and chemotherapy. While more studies are
needed, the results seen in children looked promising, and study author
Arne Simon, MD, says specialists should consider standardized honey when
confronted with wounds that refuse to heal.
Another study is underway at the Red Cross War Memorial Children's Hospital
in Cape Town, South Africa, comparing a standard treatment with honey-based
antibacterial wound gel product in approximately 80 children with burns.
Manuka honey has used in Iraq where it produced good results at a makeshift
clinic in the treatment of children with burns set up by US armed
forces. Honey is an ideal affordable first aid dressing material,
especially for emergent situations where standard medications and equipment
are not readily available, such as war-torn or earthquake-stricken regions.
It is suitable for treatment of burns, where emergency cooling with
contaminated water can lead to infection.
Maggots have been used for centuries to help heal wounds, especially by
military surgeons who noted that soldiers whose wounds became infested with
maggots healed better. The beneficial effects of therapeutic maggots were
first observed during the Napoleonic war by a surgeon who noted that
soldiers whose wounds had become infested had an improved prognosis.
When novel surgical techniques and antibiotics were discovered during WWII,
maggot debridement therapy (MDT) moved into the background.
Medicinal maggots (sterilized larvae of the green bottle fly Lucilia
sericata that do not reproduce nor feed on live tissue) work as biochemical
debriding agents. They ingest bacteria and degrade them in their intestinal
tract. They also secrete an enzyme that disinfects the wound, dissolves
necrotic tissue, and stimulates wound healing. Maggots are now being used
against a wide spectrum of wounds and are proving to be effective against
MRSA and other multiresistant microorganisms. They also appear to be more
cost effective than other methods of wound healing.[12,14,15]
"Studies indicate that about 40% to 50% of wounds treated with maggot
therapy as the last alternative before amputation were healed, and the
limbs were saved," according to Dr. Ronald Sherman, a pathologist at UC
Irvine who has been breeding and studying maggots for years. The practice
has been growing by about 25% a year in the United States according to
Maggots received marketing clearance as "medical devices" by the FDA in
January 2004, making them the first live organism marketed in the United
States. Therapy is currently reimbursable by Medicare.
About 50 centers in North America, 400 in the United Kingdom, more than 140
in Germany, and more worldwide currently offer maggot therapy as an option
for treatment in wound care.
Leeches in Wound Healing
The leech, once an indispensable part of the practice of medicine in the
19th century only to be abandoned in favor of scientific medical advances,
is seeing a renaissance in the area of modern plastic reconstructive
surgery -- particularly in microsurgery transplantation.
In the United States, medicinal leeches (Hirudo medicinalis) were cleared
as a medical device in June 2004 by the FDA (shortly after maggots received
clearance) and are used today throughout the world as tools in skin grafts
and reattachment microsurgery.
The renewed interest in leeches can be ascribed to 2 Slovenian surgeons who
described their use to prevent venous congestion of skin-flap transplants
in an article in the British Journal of Plastic Surgery in 1960.
Leeches work by creating a puncture wound that bleeds for hours, while
anesthetizing the wound, preventing clotting and dilating vessels to
increase blood flow.
Then in 1985, Joseph Upton, a Harvard plastic surgeon, used leeches in the
reattachment of an ear in a small child. Ears have been notoriously
difficult to transplant successfully due to the clotting of minute blood
vessels during the procedure. The use of leeches saved the boy's ear.
The medical literature describes countless cases of the use of leeches to
relieve venous congestions following reattachment or transplantation
surgery of fingers, toes, ears, penis, and other skin-flaps; in addition to
breast reconstruction, reduction, or augmentation procedures where
engorgement of the nipple can be a complication.[21,22]
Leeches possess properties that make them uniquely able to assist with
venous compromised tissues. Their saliva contains:
Hirudin, a direct thrombin inhibitor;
Hyaluronidase, which increases the local spread of leech saliva through
human tissue at the site of the wound and also has antibiotic properties;
A histamine-like vasodilator that promotes local bleeding; and
A local anesthetic.
Aeromonas hydrophila infections are a recognized complication of
postoperative leech application, with reported incidences ranging from 2.4%
to 20%. Prophylactic antibiotics are often recommended. In the event
infection develops, early diagnosis and immediate initiation of an
empirical intravenous antibiotic therapy are essential.[23-25] Another
major concern in the use of leeches is their migration from the surgical
site, possibly into the body or the wound itself. One study suggested a
possible simple solution, which was to attach 1 end of a surgical suture to
the leech and tie the free end to a firm object or dressing.
While leeches still aren't a surgeon's first choice, they are considered in
a transplant that has failed for lack of venous outflow on the patient that
has been put on heparin or other anticoagulants, and has undergone repeat
surgeries in which as many of the small veins have been attempted to be
connected. Randomized-controlled trials are pending to elucidate the
benefit of H medicinalis in accordance with evidence-based criteria.