Leeches can be used to treat a complication of reconstructive surgery

So Wisconsin doctors devised a bell-shaped glass and metal device, measuring about 1.3 cm, or half an inch long.

The device, patented by the Wisconsin Alumni Research Fund, has fluids running through it, irrigating the wound and pulling the blood through.

Human tests should begin soon, say researchers.

Centuries-old treatment

Nadine Connor, a psychologist at the university who is working on the device, told Reuters news agency: "Some women have said having this [real] leech on their breast is the worst part of their breast cancer."

Leeches have been used to treat conditions such as venous congestion, a potential complication of reconstructive surgery - such as that done after breast cancer operations

Although the arteries pump blood into the reconstructed tissue, the associated veins may not let the blood flow out if they have become clotted.

If there too much blood builds up in the tissue, the organ may be deprived of oxygen and other nutrients and die.

But the team say their new device will not look like a real leech: "Not that leeches aren't beautiful, because of the psychological impact that leech use has on patients."

Dr Judy Evans, a plastic surgeon at Plymouth's Nuffield Hospital and a spokesperson for the British Association of Aesthetic Plastic Surgeons, told BBC News Online it has been difficult to develop an alternative to real leeches.

Dr Evans, who has used the animals herself, said many researchers were trying to find an alternative to leeches, and she welcomed the US research.

She said: "The problem with leeches, apart from people not liking them is that they do carry an organism, a rather nasty bacterium.

"If that gets into the patient, they can get very seriously ill. So patients need to be treated with antibiotics."