How Amputation Works

Reasons for Amputation

Traumatic injury surgeons attempt to save an infected leg from amputation in the operation room at the U.S. Army Mobile Army Surgical Hospital (MASH) in Muzaffarabad, Pakistan.
Traumatic injury surgeons attempt to save an infected leg from amputation in the operation room at the U.S. Army Mobile Army Surgical Hospital (MASH) in Muzaffarabad, Pakistan.
Paula Bronstein/Getty Images

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:

  • Traumatic Injury: Car accidents, severe burns and gunshot wounds are all possible causes of traumatic injury. Blood vessels and other body tissue components can be ripped or shredded beyond repair by these types of injuries, leaving no other option but amputation. In the age group of 50 and younger, traumatic injury is the leading cause of amputation.
  • Disease: A variety of different diseases can irreversibly destroy body tissues. Peripheral artery disease (PAD) is the leading example. In this disease, blood vessels are hardened such that life-sustaining blood is blocked from reaching tissues in the body's extremities. These tissues eventually die for the reasons explained in the previous section. Diabetes contributes to PAD, while at the same time causing nerve death, called neuropathy. Patients suffering from neuropathy lose their sense of touch and are more prone to cuts, which heal more slowly due to impaired circulation. It is no wonder that more than 90 percent of the amputations performed in the United States result from this scenario.
  • Cancer: While cancer can also cause severe damage to body tissues, cancer can also necessitate an amputation for a different reason: to keep malignant tumors from spreading to other parts of the body.
  • Congenital amputation: Within the womb, blood flow to a developing limb can be constricted by other bands of tissue. As a result, the limb can be lost permanently, and the baby is born with what is termed a congenital amputation.

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.­