Amputation of a Limb

  "A photograph of a dog 6 months after a hind limb
   amputation for osteosarcoma."

Limb amputation is a surgical procedure commonly performed in dogs and cats to remove a diseased or injured limb, either front or rear. Amputation may be a life saving procedure for animals that only minimally impacts their comfort and quality of life.

Owners should have a clear understanding of why the surgery is being performed and what can be expected afterwards. Pets function exceptionally well on three legs and are able to run, walk, and play without pain or discomfort. Pets do not seem to suffer the psychological distress of losing a limb the same way a human does. Vets have found amputations do not seem to slow animals down or even bother them very much. Most animals will tolerate an amputation extremely well and have a really good quality of life afterwards.

Most animals that have had amputations have probably already learned to walk on three legs and owners may not realize this. Often, the pet may be relieved to have the painful leg removed and may feel even better after the amputation, than it did before surgery.

Another aspect to consider is the long term effect of an amputation. An early amputation may be more beneficial for your pet than for it to go through multiple painful surgeries to save the leg.

Prior to general anesthesia your vet may run blood work to check for other health problems. Chest X-rays are often taken when tumors are present to determine if there is evidence that the tumor has spread to the lungs. If cancer is suspected, x-rays are taken of the limb and typically a biopsy will be obtained to confirm the diagnosis prior to amputation. Pain medications are important both before, during and after amputation, to ensure your pet’s comfort throughout the procedure.

The majority of dogs are up and around the day following the amputation. Some assistance may be necessary to help larger dogs outside, particularly if they are overweight or were not lame before surgery.

After surgery there will be an incision that needs to be assessed daily for swelling, redness or discharge. Contact your veterinarian if you have questions or concerns. Stitches or staples need to be removed in 10-14 days. Do not allow your pet to lick or chew at the surgical site. An Elizabethan collar may be necessary to prevent this from occurring.

  "Audrey: 2 weeks post limb amputation"

One of the most common reasons for a limb amputation in dogs is treatment of osteosarcoma, which is the most frequently diagnosed canine bone tumor. This tumor tends to occur in large and giant breed dogs. It may occur in young dogs (12 to 18 months of age), but is more common in older animals. The most common locations are just above the carpus (wrist), the proximal humerus (just below the shoulder joint), and around the bones of the knee joint. Amputation is an excellent way to control the local disease, the bone cancer on the limb. Osteosarcoma is often a malignant tumor, resulting in the spreading of the cancer to other organs.

Soft tissue sarcomas are another type of tumor that can develop on the limbs. These tumors are malignant, but tend to be slow to spread to other parts of the body. They are locally aggressive (they damage and invade the structures at their location). If they occur on a limb it is often difficult to get rid of the tumor in its entirety while maintaining muscles, tendons, nerves, ligaments and bone needed for normal limb function. Thus, amputation may be the surgical procedure of choice.

In addition to surgery, radiation therapy or combinations of radiation and chemotherapy may be appropriate for certain limb tumors. Treatment options can be discussed with your veterinarian or with a surgical or oncological specialist.

Amputation may be recommended when there are multiple fractures and extensive trauma to the muscles, tendons and ligaments of the limbs. Nerve damage or a severely broken limb can also result in amputation. Amputation may be the treatment of choice for limb trauma where nerve supply or blood supply is severely damaged or bone and soft tissue injury is beyond what can be repaired by modern surgical techniques. Damage to the nerves that supply the limb, for example following trauma that results in pelvic fractures, may be irreversible, resulting in a non-functional limb that drags. This may result in abrasions of the paw through failure of the animal to pick up the leg properly. Amputation may be indicated in such cases.

Preoperative tests depend in part on the age and general health of the animal as well as the cause of the limb amputation. For most situations, radiographs, complete blood count, and serum biochemical tests may be necessary.

The procedure requires general anesthesia to induce complete unconsciousness and relaxation. In the usual case, the pet will receive a pre-anesthetic sedative-analgesic drug to help him relax, a brief intravenous anesthetic to allow placement of an endotracheal tube, and subsequently inhalation (gas) anesthesia and oxygen during the actual surgery.

Complications occur in less than 5% of animals after limb amputation. The most common complications of limb amputation are wound infection, wound breakdown (opening up of the incision), and accumulation of fluid underneath the surgical site (i.e., seroma formation).

The aim of chemotherapy in cats and dogs is to kill the tumor but not decrease quality of life. The majority (more than 85%) of animals undergo chemotherapy with few problems. However, 5% to 15% of cats and dogs may require hospitalization to treat chemotherapy-induced problems, such as bone marrow suppression, infection, and dehydration from vomiting and diarrhea. The risk and severity of chemotherapy complications or side effects are often dependent on the drug used and should be discussed with your veterinarian.

The majority of dogs are able to walk unassisted within 12 to 24 hours after limb amputation. Dogs should be encouraged to walk and exercise to improve the speed of recovery. The surgical wound should be checked twice daily for signs of infection or imminent breakdown. These signs include redness, swelling, watery to thick discharge, and pain.

The vast majority of dogs will adapt very well after limb amputation, even if they are large breed, overweight, or arthritic in other joints. It usually takes 4 weeks or less for the dog to adapt to life on three legs, especially if owners have a positive attitude towards their dog and its treatment.

The prognosis for cats and dogs with primary bone tumors is guarded and depends on the tumor type and affected bone. For dogs with long bone osteosarcoma, the median survival time with palliative treatment alone is 90 to 150 days, with 45% of dogs alive at 6 months and 15% alive at 12 months after diagnosis. In contrast, the median survival time following surgery and chemotherapy is 235 to 366 days, with up to 65% of dogs alive at 12 months and 28% alive at 2 years.

Compared to dogs, cats with long bone osteosarcoma have a low metastatic rate (less than 10%) and the median survival time after amputation alone is over 350 days (and up to 4 years).

For dogs with long bone chondrosarcoma, the median survival time after limb amputation alone (i.e., no chemotherapy) is 540 days. Approximately 20% of dogs with chondrosarcoma develop metastases (spread to other areas), but these usually occur late in the course of the disease. Chemotherapy does not decrease the metastatic rate or improve survival time in dogs with chondrosarcoma.

Appendicular fibrosarcoma and hemangiosarcoma are rare and thus the prognosis is difficult to determine. Metastasis is relatively common, however, in dogs with hemangiosarcoma. For this reason, survival times are generally poor, and less than 10% of dogs alive at 12 months after limb amputation.

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