Limb Sparing in Dogs
"Limb sparing" (also known as "limb salvage") is a surgical procedure that provides an alternative to amputation in selected dogs being treated for bone tumors. Most dogs function very well with an amputation—dogs are not burdened by the psychological aspects of missing a limb in the same way, as are humans. However, there are some dogs that have concurrent orthopedic problems, such as severe arthritis, that might not do as well on three legs. The idea of preserving a limb in dogs is not new, but it is only recently that advances in medical technology have made this procedure possible. The goal in limb sparing is to remove the diseased bone and surrounding tissues while still preserving the function of the remaining limb. The piece of diseased bone that is removed is replaced by a combination of healthy bone from a donor and bone graft from other parts of the patient's body. While much of the leg's function is preserved, there is decreased range of motion in the treated limb, which results in limited activity for the dog.
There are several restrictions, as to which tumors and what size and location can be treated with limb sparing, so a thorough evaluation of each patient is required. This evaluation consists of complete blood cell count, blood chemistries, and urinalysis; radiographs (X-rays) of the primary tumor site and the lungs; tumor biopsy; and often other tests such as CT, MRI or bone scan to thoroughly evaluate the extent of the tumor.
Limb sparing is performed in conjunction with chemotherapy (and in some instances, radiation therapy as well). The biopsy results help determine which type of additional therapy is required. Chemotherapy helps control the growth of any tumor cells that have spread beyond the primary tumor site to areas elsewhere in the body such as the lungs and other bones.
Surgery and chemotherapy are well tolerated by most dogs. The surgery requires a five to seven day hospitalization. After the surgery your dog may be in a padded bandage or splint which will need to be checked periodically. Chemotherapy is done on an outpatient basis, but does require multiple visits to the hospital for treatment and monitoring. Periodic radiographs of the limb are taken to evaluate the rate of healing at the surgery site. Chest radiographs are taken to monitor for spread of the tumor.
At this time, the only good results are in dogs with tumors of the distal radius (the "wrist" joint). More than three-quarters of these patients return to near normal function. Dogs with tumors of the proximal humerus ("shoulder" joint) only did well about 10% of the time. Dogs with tumors in the tibia did not do well if arthrodesis ("joint fusion") of either the tarsus ("ankle") or the stifle ("knee") joints was required. Generally, at this time, limb sparing is recommended only for tumors of the distal radius.
While limb sparing can prolong a good quality of life for a dog with bone cancer, it is important to realize that a complete cure is unlikely. It is our expectation that dogs with osteosarcoma treated by limb sparing and chemotherapy may be free of tumor for about one year. Dogs receiving only palliative therapy to control symptoms such as pain (which can include pain medication, radiation therapy, or amputation alone) have an average survival of about four to five months. It is important that you understand all your treatment options -- the risks, benefits, common complications, costs, and time commitments. Please discuss any questions and concerns with your veterinarian.