Reattaching a finger is a painstaking process and requires repair of the bones, tendons, nerves and blood vessels that have been severed. The majority of these injuries occur when a patient has been using a table saw while at work. In many cases blood supply can be re-established by repairing the arteries that bring blood into the finger, but the small veins on the surface of the finger may be so damaged that egress of the blood back to the heart is compromised. Interestingly, flaps used to create a new breast after a mastectomy may also become engorged with blood that cannot find its way out of the affected area.
Did you know that hundreds of years ago Hirudo medicinalis, the medicinal leech, was used to treat everything from laryngitis to yellow fever? Today the leech, which costs about $7 per worm, is used most often after trauma, such as the loss of a finger or limb. Plastic surgeons can rely on this therapy to rescue skin flaps compromised by venous congestion after surgery. Once the 1- to 2-inch long worm is placed into position, it can consume up to five times its body weight in blood (about 10 milliliters). The animal injects an anesthetic from it's saliva so that the bite does not hurt. During its meal, the leech also injects an anti-coagulant, known as hirudin, which thins the blood and helps to keep the area bleeding after the leech is removed.
In my experience patients (and nurses who have to reapply the leeches!) are remarkably willing to comply with leech therapy. So much so that we recently had a leech shortage at Vancouver General Hospital for a short period! The leech is a great example of a medical therapy that was discovered in a different era, yet still has a real effect on medicine today.