Are Leeches still used in Medicine?
In the past, considered mere relics of the medieval era, surgeons now embrace parasites as a valuable treatment option for patients undergoing transplants and plastic surgeries.
Ellie Lofgreen found herself at the University of Utah Hospital during the summer, battling a rare form of cancer known as synovial sarcoma. In an extensive surgery, doctors successfully removed a tumor resembling the size of a small cantaloupe that had entwined her knee joint. Additionally, they had to excise a portion of bone and muscle linked to the knee.
A metal implant was inserted in her leg to restore functionality, which was then concealed by a substantial flap of muscle and skin taken from her upper thigh. Unfortunately, after a few hours, the transplanted tissue exhibited a disconcerting purple hue, indicating to the medical team that it was experiencing vascular compromise and potential necrosis.
The medical team’s proposed treatment for saving the graft was unexpected for Lofgreen: leeches.
Lofgreen, a 31-year-old resident of Idaho, was completely taken aback. “I was completely shocked,” he says. “My first thought was, Anything but that.”
Using leeches in modern Medicine often surprises patients due to their historical association with quackery. However, their use in plastic and reconstructive surgery has become more common since 2004. The U.S. Food and Drug Administration approved leeches as a medical device during that year, allowing them to relieve congested veins and restore blood flow in compromised grafts.
In instances where doctors connect blood vessels in a graft to surrounding tissue during tissue attachment procedures, the goal is to ensure continuous blood supply.
Typically, these surgeries are successful; however, in cases where complications arise, the initial course of action involves returning the patient to the operating room for a thorough evaluation of the stitches and the reattachment of blood vessels. However, it is important to note that although uncommon, this solution may also prove unsuccessful.
According to Jayant Agarwal
Chief of plastic surgery at the University of Utah, veins are extremely delicate. Even if a connection is successfully made, blood flow may still be restricted if a vein end is damaged in an accident. Additionally, locating a vein in a severed finger, for example, can be challenging. When the connection is not established, blood can accumulate in the transplanted tissue, which is when leeches become useful.
Jeffrey Janis, a plastic surgery expert at the Ohio State University Wexner Medical Center, explains that leeches provide temporary life support until the body’s blood vessels grow into the transplanted tissue. Without this assistance, the tissue can die.
The origin of medical leeches
can be traced back to various species, with the European Hirudo medicinalis and Mediterranean Hirudo verbena being the most commonly utilized in Medicine. These leeches possess three jaws resembling saws, each equipped with around 100 teeth, which they employ to pierce the skin.
Medical leeches have been bred in laboratories across countries like the United Kingdom, the United States, France, Turkey, and Ukraine for several decades. Carl Peters-Bond, who works at Biopharm U.K., a leading supplier of medical leeches to hospitals worldwide, has been involved in this breeding process for almost three decades.
According to Peters-Bond
Raising a leech suitable for medical purposes takes approximately one to two years. The process entails feeding them at three weeks, eight to 10 weeks, and again at four to five months, followed by up to two years of starvation. “We ensure that the leeches we ship have an empty gut,” he asserts.
Peters-Bond swiftly prepares between 12 and 60 leeches in a gel-filled container and dispatches them to a hospital upon receiving an emergency call. Sometimes, hospital pharmacies proactively request and store these medical leeches in a refrigerator, anticipating the need for patients requiring finger reattachment, ear reattachment, or breast reconstruction surgery. However, it is important to note that these leeches have a three-month shelf life, as Peters-Bond highlighted.
The mechanism of action of leech therapy
When a leech bites, it injects saliva containing compounds such as hirudin and calin, which prevent blood from clotting. Additionally, the leech saliva contains substances similar to histamine that dilate blood vessels and enhance blood flow. Physicians may use anticoagulants like heparin in reconstructive surgeries to prevent blood clots.
However, the active bloodsucking action of the leech is still necessary, according to Agarwal. The leeching process can last for three to 10 days or more, depending on the graft size and the degree of congestion. During this time, patients are supervised by medical staff in the hospital.
The engorged leeches are replaced with new starved ones regularly, as each leech can only be used once. After serving their purpose, the leeches are drowned in alcohol.
During two weeks, Lofgreen underwent a treatment where over 100 leeches were used to drain her discolored tissue. With the assistance of nurses and suggestions from the public through Facebook, her family gave each of these invertebrates a name.
Among her favorites were Aleecha Keys, Clint Leechwood, Sir Leech-a-lot, and Queen Laleecha. Every four hours, a nurse would introduce a new leech, which would suck blood between 15 to 120 minutes before detaching and ending up on her bed. Doctors provided blood transfusions throughout the therapy to replenish the blood she lost.
However, getting the leech to attach was often difficult and even trickier to keep it in place. Initially, nurses used a plastic cup inverted and taped onto Lofgreen’s skin to contain the leech. Unfortunately, the leech would often find a way to escape. The nurses then tried using a piece of gauze with a hole where they wanted the leech to attach, hoping it would discourage them from wandering off to the surrounding skin. However, this method could have been more foolproof too. The most effective solution was the watchful eyes of Lofgreen’s mother and sister. Throughout the day, they took turns keeping an eye out for any rogue leeches and would immediately inform the nurses. Although Lofgreen felt no sensation when the leeches bit into the transplanted tissue, it was quite painful when they bit elsewhere. She describes it as feeling like pins and needles.
With time, her skin’s initially dark and necrotic tissue gradually turned a light purple shade, giving it a more normal appearance. Lofgreen acknowledges the effectiveness of using leeches in her treatment, as they contributed to the successful healing process.
However, upon her return home, a small flap area became infected and required removal. It is important to note that this infection was unrelated to using leeches and instead stemmed from an open wound. Regardless, she attributes the majority of the saved transplanted flap to the presence of these slimy, slithering creatures.
Our Last Words
Since 2013, Agarwal and his colleagues at the University of Utah have created a mechanical leech that can mimic the suction of real leeches while delivering an anticoagulant.
The prototype consists of an array of needles that pierce the skin, with a central needle supplying heparin to the tissue and surrounding needles connected to a pump to suction blood. This small device allows doctors to control the volume and rate of blood taken, something that’s not possible with real leeches. Currently, the team is focused on perfecting the delivery of the anticoagulant into the attached tissue.
Other scientists have also developed similar prototypes, some of which have been tested on animals. However, these mechanical replacements are still being prepared for use in humans. Despite this, real leeches play a valuable role in modern Medicine.