|
The
leech was indispensable in 19th Century medicine for bloodletting,
a practice believed to be a cure for anything from headaches to
gout. Leeching was largely abandoned as medical science advanced,
only occasionally being called upon to treat bruising and black
eyes. However, the medicinal leech is making a comeback in modern
medicine thanks in part to the work of Dr. Roy Sawyer, an American
scientist who established the world's first leech farm.
Based at
Hendy near Swansea, South Wales, Biopharm is home to over 50,000
leeches which are supplied to hospitals and research laboratories
around the world.
Thousands of patients owe the successful reattachment of body parts
to miraculous technological advances in plastic and reconstructive
surgery; at least some of these operations might have failed if
leeches had not been reintroduced into the operating room. The appendages
reattached include fingers, hands, toes, legs, ears, noses and scalps.
The
pioneering use of leeches in modern plastic and reconstructive surgery
can be attributed to two Slovenian surgeons, M. Derganc and F. Zdravic
from Ljubljana who published a paper in the British Journal of Plastic
Surgery in 1960 describing leech-assisted tissue flap surgery (in
which a flap of skin is freed or rotated from an adjacent body area
to cover a defect or injury). These surgeons credit their own use
of leeches to a Parisian surgeon, one Philippe-Frédéric, who reported
in 1836 that he had used leeches to restore circulation following
reconstruction of a nose.
The
rationale behind the use of leeches in surgical procedures is fairly
straightforward; nonetheless, it is subject to misunderstanding,
even by clinicians. The key to success is the exploitation of a
unique property of the leech bite, namely, the creation of a puncture
wound that bleeds literally for hours. The leech's saliva contains
substances that anaesthetise the wound area, dilate the blood vessels
to increase blood flow, and prevent the blood from clotting.
Microsurgeons
today are adept at reattaching severed body parts, such as fingers.
They usually have little trouble attaching the two ends of the arteries,
because arteries are thick-walled and relatively easy to suture. The
veins, however, are thin-walled and especially difficult to suture,
particularly if the tissue is badly damaged. All too often the surgeon
can get blood to flow in the reattached arteries
but not
veins. With the
venous circulation severely compromised, the blood going to the reattached
finger becomes congested, or stagnant; the reattached portion turns
blue and lifeless and is at serious risk of being lost. It is precisely
in such cases that leeches are summoned.
|
