How Amputation Works

Severe injury or disease can sometimes damage portions of the body beyond their capacity to regenerate or heal. When body tissue dies, infection can set in, causing dangerous conditions such as gangrene. The infection sites provide a stronghold to dangerous bacteria, which can spread to other parts of the body.

A key cause of the tissue death that leads to infection is a lack of blood flow. Blood brings vital nutrients and oxygen to the individual cells that make up your body tissues. When disease or injury damages blood vessels beyond repair, tissues supplied by those blood vessels die, and dangerous infection can set in. When there is no hope that damaged or infected tissue can be restored to its healthy state, an amputation might be necessary to protect the rest of the body from the spreading of infection.

Amputations can be performed at a variety of different sites, depending on the location of the damaged tissues. As little as a single toe might require amputation, or as much the entire lower body from the hip down. Generally, amputations are performed on portions of the arm or leg and are termed upper extremity or lower extremity amputations accordingly.

Listed below are some of the different ways that tissues can be damaged to the point that an amputation is necessary:

The National Limb Loss Information Center (NLLIC) provides some relevant statistics regarding amputations. According to their numbers, one out of every 200 Americans is an amputee. That's a total of approximately 1.7 million people. The rate of amputations caused by traumatic injury and cancer have dropped by around 50 percent over the past 20 years, but unfortunately the rate of amputations due to diabetes and peripheral artery disease is on the rise. Underlying causes for this trend might include the escalating rate of obesity and increasing average life spans.

Now that we've seen what conditions might require an amputation, let's look at how amputation surgeries have evolved through the years.­

Archeological findings reveal that amputation procedures have been performed since ancient times. The earliest amputations, though, were performed mainly to remove tissue that was already dead. The reason for this limitation is that early surgical techniques could not control the blood loss, called hemorrhaging, that results from cutting healthy arteries.

Surgeons in ancient Greece and Rome dealt with the problem of hemorrhaging by introducing the technique of tying off, or ligating, blood vessels during surgery. Surprisingly, their techniques appear to have been forgotten for many centuries. It was during these times that blood vessels were instead cauterized using hot irons or boiling oil.

Advancements in amputation surgeries have tended to follow major wars. The techniques introduced by French military surgeon Ambroise Paré are a good example of this. Due to the rise of gunpowder and the weapons of war associated with it, Paré needed more effective methods of treating soldiers with devastating battlefield injuries. Among his several important contributions, Paré reintroduced the technique of ligating blood vessels

in 1529.

Other notable advancements throughout history include the introduction of the tourniquet in 1674, which enabled further control of blood flow during the amputation procedure, and one more innovation that patients undoubtedly appreciated -- anesthesia. It's hard to imagine, but anesthetic gases weren't developed until the 1840s.

These developments were all put to extensive use during the American Civil War, in which more than 50,000 amputations were performed. The lead Minie ball bullets of this era pulverized tissue like no weapon before, explaining why 75 percent of all battlefield surgeries were amputations.

By today's standards, battlefield amputations of the American Civil War were primitive. For one thing, the concept of maintaining a sterile environment, free from germs, had not been developed. Blood-spattered surgeons often operated without so much as washing their hands, barely taking the time to rinse off their tools between surgeries. The focus was instead on speed. To cycle through as many patients as possible, the surgeries were performed quickly -- usually in about 10 to 15 minutes.

The surgeon would knock out the patient with a chloroform-soaked rag, and then quickly apply a tourniquet above the injury site before using a sharp knife to slice through the skin and muscle. The bones were next sawed through -- earning Civil War surgeons the nickname "Sawbones" -- and the blood vessels were tied off with sutures. Finally the skin was closed around the amputation site, leaving a hole from which fluid could drain. Infamously, the amputated limbs were thrown out, building up in great piles.

Death rates after the surgeries were dismal by today's standards. In fact, one out of four patients died after a typical amputation, but the mortality rate doubled if the surgery wasn't performed in the first 24 hours. The deaths were caused in part by bacterial infections termed "surgical fevers" resulting from the non-sterile surgeries. It was only just after the Civil War that British surgeon Joseph Lister advanced the concept of sterile surgery. Nevertheless, thousands of lives were saved by the round-the-clock efforts of the American Civil War surgeons.

Since historical times, great advancements in amputation techniques have been made. On the next page, find out how surgeons and patients prepare for modern day amputation surgery.

In modern times, a great deal of foresight and planning go into preparing for an amputation surgery. The patient first meets with the surgeon and other relevant medical caregivers. Together they discuss important issues relating to the surgery, and the patient is educated about the procedure and what to expect afterwards. Decisions regarding the surgery, such as the type of anesthesia to be used and the level of amputation, are all topics that are typically covered.

Arrangements to begin construction of a prosthetic device are often made before the surgery as well. A specialist called a prosthetist meets with the patient and takes body measurements so the process of constructing an appropriate prosthetic limb can begin. Often, the patient will also have meetings with a psychological counselor. Understandably, losing a limb can be a particularly traumatic concept for many patients.

The surgeon must carefully plan the surgical details of the procedure, keeping several key objectives in mind. For example, it's critical to remove all diseased or injured tissue that's unlikely to heal. Leaving damaged tissue behind would defeat the purpose of the amputation and would further impair the healing process. This goal must be ba­lanced, however, with the additional aim of sparing as much healthy tissue as possible. The surgeon will always try to preserve any healthy joints the patient may have, since a working joint can greatly improve the functionality of a

prosthetic device.

When making the decision about precisely where to amputate, the surgeon needs to be able to evaluate which body tissues have the best chance to survive. One way to make this call is to measure the blood supply to the area. For this purpose, a variety of sophisticated techniques can be used that measure factors such as blood flow, blood pressure and skin temperature.

The exception to this -- a situation where there's no time for planning -- is in the event of a traumatic injury. In an emergency situation, there are times when amputation is the only option.

Once an amputation surgery has been planned, how is it actually performed? Read about modern day amputation techniques on the next page.

The amputation surgery begins after the patient has been given anesthesia. Depending on the type of surgery and the outcome of the planning meeting, the anesthesia is either general or local. General anesthesia means the patient will be unconscious for the surgery, while local anesthesia numbs only the amputation site, and the patient remains awake through the surgery.

During an amputation, the surgeon must cut through several different types of body tissue. In the section below, we'll describe how each tissue structure must be uniquely dealt with during the operation.

Skin: The surgeon begins the surgery by cutting through the skin. The incision is planned so that it will heal quickly and leave an appropriate scar. For example, it's important that the scar doesn't end up in a location where it might rub against the connection socket of a prosthetic limb.

Muscle: Most of the tissue that the surgeon cuts through during an amputation is muscle. Many considerations go into arranging and shaping the remaining muscle tissue, which provides important padding around the bone after the surgery. This padding is vital for maintaining a healthy stump and is equally critical when it comes time to fit the patient with a prosthetic limb.

Nerves: After the nerves are cut, surgeons must take special care in how they deal with the remaining nerve stumps, which can still carry sensory signals - including feelings of pain. To minimize any pain stemming the nerve endings, surgeons cut the nerves higher up than the amputation site, and then sew the nerve endings into the surrounding tissues. This helps control unwanted regeneration of the nerve endings into a disorganized mass called a neuroma, which can be a source of pain to the patient. Surgeons minimize pain by isolating the nerve endings from any areas of motion. This includes keeping the nerve stumps away from large blood vessels, which pulse with

the heartbeat.

Blood Vessels: Surgeons ligate the cut blood vessels, tying them off firmly to control the blood flow. The surgeons also pay special attention to avoid damaging the blood vessels supplying the remaining healthy tissue. Blood flow is critical for keeping tissue healthy.

Bones: After cutting through the bones, surgeons take care in smoothing any sharp edges, which can cause pain and interfere with the healing process by rubbing on the surrounding tissues. The surgeon also considers issues of bone healing, as well as how the remaining bone will interface with a prosthetic limb.

After properly arranging the remaining muscle around the bone ending, the surgeon closes the skin around the amputation site. Empty space is minimized and tubes are included to drain any fluid that builds up after the operation. Sometimes, when the doctor suspects that factors such as disease might threaten the natural healing process, the skin is closed temporarily. The amputation site is monitored closely for infection over the next several weeks, and if the healing progresses well, the site is closed permanently.

Once a patient undergoes amputation surgery, what is the recovery process like? We'll find out on the next page.

After the amputation surgery, medical caregivers administer antibiotics and carefully control pain levels. Doctors monitor the patient closely. To speed up the healing process, doctors apply compressive bandages, which look like sleeves or sock-like dressings, to the site of the surgery. Compression is important for reducing swelling and increasing blood pressure at the site of amputation. Doctors also encourage circulation by frequent repositioning or stretching of the limb stump, which is more appropriately termed the

residual limb.

An essential part of the recovery process is physical therapy. Not only does therapy improve the healing and function of the residual limb, but it also helps to strengthen bones and muscles elsewhere in the body, which can help compensate for the missing limb. For example, a physical therapist might concentrate on helping the patient use crutches or a walker. A therapy regimen also commonly focuses on patients accomplishing activities of daily living, such as getting out of bed unassisted or dressing without help.

After the wound site is fully healed, the patient might work with a prosthetist to be fit with a prosthetic limb. The prosthetic is individually tailored to the amputee's residual limb with particular care devoted to designing the socket that provides the interface between the patient and the prosthetic. The socket can be continually resized as necessary to accommodate changes in the shape of the residual limb due to reduced swelling or muscle atrophy.

Commonly, amputees must also deal with phantom limb pain, in which patients experience sensory input that feels as if it were coming from the amputated limb. It might seem unusual that this phenomenon would occur, but it actually makes sense. Even though a portion of the body has been amputated, the sensory pathways -- from the nerve stump all the way to the sensory centers of the brain -- are left intact. As the body's nervous system tries to readjust to the missing input, activity along these pathways can be misinterpreted by the brain as coming from the missing limb. Because activity along these sensory pathways often originates from the nerve stump, one treatment for phantom limb pain is to reposition the nerve endings with another surgery.

Despite the challenges faced by amputees, most learn to adapt to their individual situations remarkably well. Many are able to compensate for their lost abilities with the help of prosthetic devices. As the field of prosthetics continues to advance, the types of capabilities that prosthetics are able to restore to amputees will only continue to grow.

If you'd like to know more about amputation, then follow the links on the next page. You'll find plenty of great information there.