The Mechanical Leech

By Kerrie Pinnock

ELE482 Biomedical Seminar III Monday April 29, 2002

Leeches have been used to treat many

different ailments from headaches to

stomach aches in ancient Egypt. Napoleon’s

military surgeon, Francois-Joseph-Victor

Broussais who was such a firm believer in

the medical benefits of leeches that in 1833;

he had more than 40 million imported into

France. In today’s medical field leeches are

used mostly to treat venous congestion.

Venous congestion is a post-surgical

complication that can occur after

reconstructive surgery. Venous congestion

is a complication that can happen after head,

neck, or breast reconstruction, limb or digit

reattachment, or other complicated

procedures where tissue is moved from one

place to another. Leeches increase the

blood flow to compromised tissue.

Complications happen as the arteries pump

blood into the reconstructed tissue, but the

associated veins do not let the blood flow

out, usually because the veins have become

clotted. The excess blood in the tissue, if

severe enough, can deprive the tissue of

oxygen and other nutrients and can cause it

to die.

In cases of venous congestion where

reestablishing the flow of blood is essential,

leeches have great therapeutic value

because, as they consume their meal of

blood, they promote blood flow through the

tissue. Even after a leech detaches from the

body, the anticoagulants it secreted into the

tissue allow the wound to ooze blood for

hours afterward. This oozing promoted by

the leech's natural anticoagulants also allows

blood to continue flowing through the tissue.

The mechanical leech was developed at

UW-Madison. The way it works is:

1.Tube delivers a solution containing

Heparin, an anticoagulant, to the wound.

2. Miniature bellows move the tube up and

down, preventing blood from clotting at the

bottom.

3. Actuator-driven disk rotates tube, also to

prevent clotting.

4. Holes in the cone release the solution to

cleanse wound.

5. Suction draws blood and solution out to

promote circulation

This mechanical leech has many advantages

for example it can penetrate a deeper level

under the skin, tapping into larger blood

vessels and treat a larger area of tissue.

Leeches are not sterile and can cause

bacterial infections. Nurses and pharmacists

tend not to like working with leeches

because they can sometimes slip off patients

and reattach themselves to other parts of the

body not in need of therapy. Most patients'

don’t enjoy having leeches attached to their

bodies. The mechanical leech will be able to

reduce this psychological stress.

The mechanical leech has only been tested

on pigs’ skin. Michael Conforti and Nadine

Connor are currently working toward a

mechanical leech that is smaller and easier

to use. Within the next three years this

product should be ready for human patients.

http://www.popsci.com/popsci/medicine/article/0,125

43,230229,00.html

http://www.otoweb.org/news_folder/mech_leech/mec

h_leech_B.htm

http://www.virginia.edu/topnews/releases2000/cottler

leech-dec-14-2000.html

http://www.news.wisc.edu/newsphotos/leech.html