Pathology
An amputation is the severing of a body part. Amputations are classified as partial and complete and if the amputation was a clean cut, a crushing amputation or an avulsion amputation where the amputated limb is pulled right off of the body. The avulsion amputation has the worse prognosis with the zone of injury being very wide. When an amputation occurs from the mid-palm to the level of the shoulder, it is a true emergency and must be replanted no more than 4-6 with warm ischemia but can be extended to 8 hours if it is cold ischemia (when the part is placed in an ice bath) after injury because the oxygen demands and metabolism of the muscles is high causing tissue death or necrosis if the blood supply is not restored within this time period. The necrotic changes that have taken place in the amputated part lacking oxygen will cause a dumping of this necrotic material into the bloodstream and cause a systemic collapse called Disseminated Intravascular Coagulation (DIC) that risks the persons’ life who is undergoing a replantation. If this occurs, the amputated part must be removed.
When amputation occurs, the amputated part must be immediately wrapped in gauze moistened in saline and placed in ice slush made by crushing ice and placed in zip lock plastic bag and then placing it in a cooler while transporting it to ROC for replantation. Amputations from mid-palm to fingers have more time to be replanted because fewer muscles are found in this area. Time to replantation of fingers can be successfully done after 15 hours post amputation for this reason.
Treatment
The treatment of an open wound begins with obtaining a clear history to determine the lacerating instrument, the position of the arm and hand during the laceration, the direction and depth of the laceration. The exam will confirm the injured tissue and the history will provide the direction the wound should be extended during exploration. The cleaning of the wound, repair of muscle, artery and tendon is done best with the use of a microscope or magnifying glasses called loupes. The improved magnification allows for more accurate approximation of the injured tissue. Tetanus is updated if it has been longer than 10 years since receiving a tetanus shot or if the wound is a dirty, then the tetanus is updated if it has been five years since receiving a tetanus shot. This is to avoid the danger of acquiring gas gangrene that can be deadly. The use of oral antibiotics for one week after a repair is used as a prophylaxis to avoid the risk of infection. Special splints are applied after surgery to avoid certain movements. The injured extremity must be elevated to at least heart level to avoid swelling of the limb that can cause moderate pain, cut off the blood supply and delay wound healing.
The treatment of an amputation starts immediately after amputation. That is placing the amputated part in cold ice slush and transporting it to a replantation facility like ROC. Upon arriving in an emergency facility, the patient is prepared for surgery while the amputated part is taken to the operating room, cleaned and dissected out under a microscope, preparing it for replantation. Replantation is successful with amputations beginning at the most distal joint of the fingers (DIP joint) and more proximal amputations above the elbow. That is because the arteries and veins become too small to repair if it is beyond the DIP joint which is at the base of the nail. During a replantation, the bone is fixed first, followed by the repair of the tendons, then the nerve, then whether you fix the arteries or veins first is surgeons’ choice since some prefer to fix the vein first to prevent excessive bleeding from the veins and others prefer fixing the arteries first to more easily visualize the veins.
Amputations that are from the forearm to the shoulder are more successful if it occurs in patients younger than 15 years of age, is a clean cut and the part is brought for amputation immediately. Partial amputations with skin still attached should be left attached since valuable blood supply may still be supplied but the retained tissue. If an amputation is an avulsion which is a pulling injury, or a severe crush injury, has severe contamination, extensive tissue damage, double level of injury, the likelihood of a successful replantation is significantly less. Other important factors like time from injury, level of amputation, heart disease, diabetes, renal disease, hypertension, peripheral vascular disease, advanced age and smoking habit amongst others will affect the prognosis and final decision of whether to attempt a replantation. Regardless of the type of amputation, it is imperative to bring in the amputated part immediately for the surgeon to assess the replantation potential or for the use of the amputated part as donor tissue.