Limb Sparing With Allograft, Bone Transport in Dogs

Limb sparing with allograft or bone transport is commonly used to treat dogs with the bone tumor known as osteosarcoma. These types of bone tumors invade the bone and extend to the surrounding soft tissues, being highly metastatic. The standard plan for control of a malignant bone tumor has been limb amputation, but in recent years, veterinary surgeons have turned to limb-sparing surgeries using allograft and bone transport. 

In each case, preoperative skeletal imaging is required, including computed tomography (CT), orthogonal plane radiography, and magnetic resonance imaging (MRI) of the affected limb. The nature of the tumor may be diagnosed using refined pre-operative histopathology, cytology, and appropriate staging for distal or local metastases. After the veterinarian confirms that the tumor is in fact an osteosarcoma, the limb sparing with allograft or bone transport procedure will begin. 

The exact process the veterinary surgeon uses depends on the location of the tumor and the tools available. In general, the area proximal to the bone growth will be shaved, cleansed with an antimicrobial scrub and draped to prepare for surgery. Pain management will be the main goal of the veterinary anesthetist throughout the procedure, as  bone will be cut during this type of procedure. The tumor and surrounding bone will be removed using a bone saw. It will be necessary to remove a decent amount of surrounding bone tissue, as the cells that cause a bone tumor can be found in close proximity to the tumor. To avoid a future tumor in this area, or for the cancerous cells to spread, the surgeon will remove surrounding bone as well. Once the bone has been removed, a stainless steel limb brace is then positioned to the limb to account for the missing bone. The brace is made up of a plate, screws and pins to support the limb, giving the dog mobility. Once the brace is in place, the nerves, muscles and tissues will be sutured back into the appropriate place. The surgical site will then be closed and the dog will be taken to recovery. 

The objective for limb sparing surgery in dogs is to enable complete resection of the malignant area and restore the limb function without post-surgical pain. In the clinical cases that were used on the distal radius, results are often positive with the limb function restored by pancarpal arthrodesis. 

Following a surgery, the canine will be sent home with pain medications and an antibiotic to prevent infection. Exercise will be restricted to short walks for eight weeks after the operation. A fiberglass splint will be maintained for five weeks, followed by a soft padded bandage for seven weeks. 

Limb sparing with allograft or bone transport in dogs is a procedure that usually required access to a bone bank, which is expensive to maintain and is not readily available to all veterinarians. That being said, the cost of the procedure is estimated at $2,000 to $5,000. 

Complications are a concern with limb sparing surgery, as with any other surgical procedure. Considerations of this type of canine bone procedure include tumor recurrence, infection, and implant failure. 

The need for limb sparing surgery in dogs cannot be prevented. Bone tumor growth, like all tumors, has no known cause and no known prevention method.