S T A N F O R D M E D I C I N E
Volume 16 Number 3, SPRING 1999
Stanford surgical helpers are out for blood
leeches have returned to the medical mainstream, thanks to their blood-sucking prowess.
by mitch leslie
THIRTY YEARS OF skin cancer operations had gradually whittled away William Rambo's nose, so he was delighted when surgeon Richard Goode, MD, promised to make him a new one.
But the retired Stanford professor of electrical engineering owes his new look to more than Goode's skill at molding a replacement nose from a swatch of Rambo's scalp. Because even before the anesthetic had worn off, stagnant blood began to swamp the relocated tissue, coloring it a sickly blue. To relieve the blood buildup and salvage the transplant, Goode was obliged to call for a rarely used but powerful therapy, the best available to modern high-tech medicine.
He prescribed a course of hungry leeches.
That's right, leeches. After a century of exile, these slippery creatures have crept back to medical respectability, thanks to their unmatched ability to drain excess blood from injured tissue. In prestigious hospitals across the country, leeches are biting into patients who have undergone facial reconstruction, finger or ear reattachment, and even breast reduction. Leech therapy has even passed the test of scientific scrutiny.
Stanford Hospital has developed into somewhat of a regional leeching center. Right now, stashed in an out-of-the-way refrigerator in the hospital's basement pharmacy, 30 to 40 famished leeches await a dinner invitation from a surgeon. The pharmacy ordered 600 of the bloodsuckers last year, most of which were applied to patients at Stanford or loaned out to local hospitals like the Veterans Affairs Palo Alto Medical Center.
If you're surprised, maybe even a little queasy, at the resurrection of this antique treatment, you've got company. Even the doctors who've relied on leeches for years say the astonishment hasn't worn off. "Here we are in 1999, and we're still using leeches," Goode says. "To do any good, they have to bite you, and we perceive most biting animals as bad."
A professor of surgery with 30 years of experience in facial reconstruction, Goode began leeching just over a decade ago. He was initiated into the leech club by William Lineaweaver, MD, associate professor of functional restoration, who in turn had gotten the word from colleagues at Davies Medical Center in San Francisco. Lineaweaver, who specializes in reconstructive hand surgery, had converted reluctantly. "I was appalled when people started using leeches again. I thought, 'This is terrible, this is an icky gimmick,' " he says.
For almost 2,500 years, doctors believed otherwise, relying on this icky gimmick as a remedy for almost every disorder, from "brain congestion" to appendicitis to swollen testicles. In fact, the leech was the doctor's familiar for so long that the association is preserved in the etymology of the word leech, which sprang from the Old English word læce, meaning doctor. During the Middle Ages, leech carried both meanings -- physician and parasite.
Zeal for leeches grew out of the ancient belief that an excess of blood -- either locally or bodywide -- caused disease. For tapping their patients's brimming veins, many doctors preferred leeches as a less painful and more controllable alternative to simply slicing open a vessel. Removal of a measured amount of blood -- easier to do with leeches -- could prevent that horribly embarrassing setback of having your patient bleed to death while under your care.
Leeching's golden age came during the "Leechmania" of the 18th and 19th centuries, when enthusiasm for this form of bloodletting crested. The treatment became so popular that, to satisfy American demand, the Germans were shipping 30 million leeches across the Atlantic every year. As the leeching lore from the time shows, almost no part of the body was thought too sensitive or too inaccessible for a leech. Slowed by dropsy? Half a dozen leeches at the base of the spine would prove most salubrious. Tormented by tonsillitis? Open wide so that your doctor could lower a leech secured by a piece of thread -- a "leech leash" -- into your throat to feast on the swollen glands. (And to keep the leech from rappelling farther down, he might hitch the leash around one of your teeth.) Can't sit because of burning hemorrhoids? Well, let's just say that here, leeching truly hit bottom.
We all know what happened next. Science came along and demolished the notion that blood loss was salutary and invigorating. Doctors wised up to the true causes of disease, and as a result leeches lost their license to practice. Except for sporadic use by a few diehards (Hitler and Stalin were leeched), leeches were banished to the gruesome relics display of medical museums.
Modern surgeons returned to leeching in desperation, after conventional therapies failed to dissipate the blood congestion that bedevils reconstructive surgery. Known as venous insufficiency, this complication destroys many a surgeon's handiwork. Venous insufficiency is a plumbing problem in which blood pools in damaged tissue because the veins that normally provide drainage have been severed. Unless the buildup is cleared quickly, the sluggish blood will begin to coagulate, spawning clots that can plug the arteries nourishing the tissue. If this happens, the tissue will starve and die.
Venous insufficiency takes a heavy toll, but it is very hard to prevent because of the difficulty of operating on injured tissue. Consider what happens when Lineaweaver tries to reattach a finger amputated in an accident. One of the trickiest parts of this intricate work is locating and splicing severed arteries and veins that carry blood to and from the end of the finger. While firm-walled arteries are fairly easy to spot and stitch together, flimsy veins tend to crumple, disappearing among the damaged tissue. Often the veins can't be hooked up, and while blood can flow into the finger, it has no outlet and backs up like water in a leaf-choked gutter.
When Goode and Lineaweaver see flesh turning puffy and blue, the external signs of sluggish circulation, they know it's time to summon a leech. "You can think of the leech as a substitute vein," Lineaweaver says. By drinking off the excess blood, leeches prevent clotting until new veins can sprout and restore normal circulation.
Leeches arrive for work on the wards in a small plastic container. Dark olive to black topside, with a mustard-colored belly, they are about one to two inches long. Like their cousins the earthworms, they have a segmented, accordion-like body, and they sometimes stretch ribbon-thin as they crawl. The job of applying leeches often falls to nurses, who handle the animals with tongs. Protecting your hands is vital if you're a leech handler. The animals are very sensitive to the smell of blood, and hungry leeches will pounce on an open cut or scrape. To keep the animals from getting even a whiff of any wounds, leech handlers usually wear gloves.
Getting a leech to feed at the right spot can be as simple as setting it down. But even fasting leeches are sometimes refractory, refusing to eat or trying to slither away. Goode has experimented with a number of ways to encourage the leech to settle down. To put the leech right where it's needed, he sometimes slips the animal, rump first, inside a open syringe tube and then inverts the tube over the target. To coax the animal to feed, sometimes it's necessary to draw blood by pricking the skin.
Like Zorro, the leech marks its victims with a letter, using its three sharp jaws to incise a wound shaped like an upside down Y. Releasing the pent-up blood brings immediate and dramatic results. As the animal dines, tissue that otherwise would have died transforms from blue to hale pink within minutes. And the benefits of the treatment continue long after the leech has drunk its fill and dropped off. To keep its liquid dinner flowing, a feeding leech drools into the wound a mix of chemicals that prevent clotting and dilate blood vessels. (One of these chemicals, hirudin, is the most powerful anti-coagulant known and is being studied as a possible stroke and heart attack therapy.) These substances ensure the wound keeps trickling blood for hours.
A single leech, which can swallow only about a tablespoonful of blood during its half-hour to two-hour meal, usually can't do the job by itself. Repeated sessions over several days or weeks -- involving a dozen or more leeches in total -- are usually necessary. Rambo's nose required so many leeches that the pharmacy ran out (neither Goode nor Rambo can remember the exact number used) and had to order replacements, which arrived by overnight delivery.
Careful studies on animal and human subjects confirm the effectiveness of leeching. It nearly doubles the chances that a transplanted flap of tissue -- like Rambo's nose -- will survive. For a reattached finger in which the veins could not be rejoined, the improvement is even more impressive -- from a slim 15 percent to a robust 65 percent. Neither drugs nor further surgery come close to matching these numbers. In other words, the embodiment of medieval quackery qualifies as evidence-based therapy.
Leeches offer economic benefits, too. At $4.75 to $6.50 apiece, they should satisfy the stingiest health plans. They can survive for months with nothing more than the simplest quarters (a double-layered acrylic bucket dubbed the "Leech Mobile Home" by the manufacturer's promotional literature and available in one size -- double-wide) and a slightly saline solution to soak in. They aren't even fed during their stay at the pharmacy, which ensures they are bloodthirsty and ready to work when needed.
After finishing its meal, a leech's fancy turns to sleep and maybe a little sex, which means it probably won't eat again for months or even years. This makes it useless from the hospital's perspective. So after one big dinner, the leech is killed in alcohol and thrown out with the "sharps" waste like used syringes. "That's its last meal, though it doesn't know it," Goode says.
Doctors like leeches. Hospitals like leeches. Health plans like leeches. But what about patients? After all, they are the ones who have to sit still while a slimy, ravenous parasite carves open their flesh and sups their blood. Mindful of the leech's evil image, Goode considered prescribing Valium to quell his patients's fear and loathing. But he also worried how drugs would affect the leeches. Would they grow sleepy after drinking Valium-laced blood and fall off without completing their job? In the end, he decided to forgo sedatives in favor of a "leech talk," in which he gently breaks the news, "We use medical leeches," and lays out the benefits and possible complications.
And the reaction? Hardly even a shudder. With more than 20 years of leeching between them, Lineaweaver and Goode have never had a patient reject the treatment out of squeamishness. (A few of Lineaweaver's patients have demurred because they would not accept blood transfusions, which are sometimes necessary to prevent anemia caused by blood loss.)
Are patients merely gritting their teeth and enduring an unpleasant but necessary therapy? Quite the opposite. Many patients are surprisingly sanguine about the prospect of being parasitized -- and some even feel affection for the leeches. "Patients find leeches entertaining, which shows you how boring hospital life is," says Lineaweaver. He notes that one of his patients, a 10-year-old boy, gave his leeches names.
Ever the engineer, Rambo says he was intrigued and fascinated by his two leeching sessions in 1996. After undergoing so many operations over the last 30 years, he says he was eager to see the latest twist in surgical technique. He wasn't even grossed out after waking to find nurses setting a hungry leech on his nose.
Patients might sing a different tune if they felt pain. But leeches bite painlessly, and their feeding causes no discomfort. It helps that the surgery deadens the injured area, but the ability to feed unobtrusively is clearly beneficial for a parasite. Rambo confirms that while he could feel the leeches' weight and movement, he wasn't aware of any other sensations.
Leeching has some peculiar hazards that demand extra watchfulness from doctors and nurses. Excess bleeding ranks as one of the biggest post-treatment concerns, and transfusions are occasionally required to stave off anemia. Bacteria that live in the leech's intestines occasionally enter the wound and can cause infections, but antibiotics can stop the bacteria from gaining a foothold. Probably the most serious potential complication derives from the leech's wanderlust. Once sated, a leech heads for a dark, snug place to digest its big meal. Wayward leeches can burrow into wounds or enter the patient's mouth or other orifices. To prevent escapes, nurses must keep careful count of the leeches.
After pulling off such a comeback, will leeches take on more medical roles, perhaps returning to their prominence in the mid 1800s? Goode thinks not. Though they are peerless bloodsuckers, they aren't much use against most other medical problems, he says. What's more, a mechanical leech under development could cut short the leech resurgence. Essentially an automated suction cup, the mechanical leech would drain blood without the risk of infection -- and it wouldn't frighten anyone. Goode says he would use an ersatz leech, but Lineaweaver doubts it could be as effective and cheap as the real thing.
Patients might not like the substitute either. After all, a mechanical leech would deny patients one social benefit they derive from leeching: bragging rights. "In social encounters that take a one-upmanship turn, you have to have a four-way bypass to even be competitive," Rambo says. "With leeches, I'm a competitor." SM