There are multiple techniques of pelvic limb amputation possible in dogs. Options can include amputating at the mid or proximal femur (high femur), coxofemoral disarticulation or versions of a hemi-pelvectomy. There is no strong peer reviewed data to support one technique over others, depending on the reason for amputation, any of the above techniques can be utilised.
Most veterinarians feel comfortable with the high femur approach, however some of the reported concerns over this technique include stump pain/pressure sores secondary to muscle atrophy and femur bone exposure. We commonly employ the technique of coxofemoral disarticulation which is a simple extension of the high femur approach. Surgery is performed initially via a medial approach to the femur and acetabulum, initial focus being on ligating the femoral artery prior to branching in order to ensure good haemostasis early in the procedure. The disarticulation itself of the hip and acetabulum can be performed with a variety of tools (electrosurgery, cold scalpel or a tool specific for the job - hatt spoon curette). There is usually ample residual muscle for closure to provide a prominent and protective soft tissue layer over the exposed pelvis.
What has proved to be a revelation in the technique of amputation in our practice is access to the ligasure machine. Ligasure is an electronic, surgical sealing device that uses the body’s own collagen and elastin to create a permanent fusion zone. This technology can fuse vessels up to and including 7 mm, lymphatics, tissue bundles and pulmonary vasculature, and has an average seal cycle of two to four seconds in most surgical situations. During amputations we use the Ligasure Impact(TM) open instrument (picture below) which facilitates sealing of all/most major vascular structures and simultaneous division of the tissue during surgery. This greatly reduces intra-operative haemorrhage and post operative seroma formation as cut muscle bodies are less likely to bleed/ooze pose operatively. The ligasure handpiece is powered by the Medtronic Force Triad unit which although has a high initial cost outlay, has allowed us to provide a greater range of minimally invasive techniques and improved patient morbidity by reducing haemorrhage during challenging procedures. If your practice has a high volume surgical caseload, it is possible to justify purchase of the unit through reduction in surgery time and improved patient outcomes.
Clients are informed regarding possible complications prior to surgery, and although rare can include;
· Incisional bruising is common but should improve after several days
· Seroma, or fluid under the skin, may develop near the bottom of the incision in the first two weeks
· Neuroma formation: Very rarely, nerves that have been cut for amputation will form little masses of nerve tissue that can be painful. This may require additional surgery or pain medication
· Hernia formation (occasionally with hemipelvectomy)
· Hemorrhage (occasionally with hemipelvectomy)
Clients often worry about phantom pain. Pain at an amputation site is not common.
The functional prognosis for dogs treated surgically with amputation is considered very good. The majority of dogs return to a high level of activity and endurance for their age. Following the four-week recovery period, there are no recommended limitations to their lifestyle.
Rear limb amputees tend to return to near normal mobility; forelimb amputees need to adjust their gait more significantly. For the older pet, learning to move after an amputation may take more time.
A recent publication (https://doi.org/10.2460/javma.247.7.786) identified the following owner perceived outcomes in 64 dogs undergoing limb amputation;
Results—58 of 64 (91%) owners perceived no change in their dog's attitude after amputation; 56 (88%) reported complete or nearly complete return to preamputation quality of life, 50 (78%) indicated the dog's recovery and adaptation were better than expected, and 47 (73%) reported no change in the dog's recreational activities. Body condition scores and body weight at the time of amputation were negatively correlated with quality of life scores after surgery. Taking all factors into account, most (55/64 [86%]) respondents reported they would make the same decision regarding amputation again, and 4 (6%) indicated they would not; 5 (8%) were unsure.
It is encouraging to identify that many clients are pleased with outcomes after surgery. We recently removed the pelvic limb of a 60kg Great Dane who was independently ambulatory 12 hours post operatively. I think it is important to note that we reserve amputation for cases of bone neoplasia or where surgical options for trauma or other disease are unpredictable or associated with a low chance of positive outcome.
The purpose of this correspondence is to highlight;
- the value of newer haemostatic techniques (ligasure) in the comprehensive surgical management of the small animal patient
- that owner perception following most amputations is high
- that coxofemoral disarticulation is a commonly employed and successful technique for pelvic limb amputation
Dr Lucas Beierer BVSc MACVS MVerSurg DACVC-SA