Definition & Overview
Unlike some species, humans cannot grow limbs once amputated. However, there is a possibility that the limb may be reattached to its original position through a surgical procedure called replantation. The procedure involves reconnecting the bone, nerves, and blood vessels of the amputated part and its origin.
Over 90% of amputation cases involving the upper extremities are caused by trauma. Unfortunately, not all of them are good candidates for a replantation procedure. Several factors need to be considered before any attempt to reattach the amputated part can be performed. Such factors include:
- Condition of the amputated part
- Length of time the amputated part has been deprived of blood
- Mental and physical health of the patient
If the amputated part has been severely damaged or if the blood vessels have been damaged beyond repair, it is no longer possible for a doctor to reattach it.
Moreover, amputated parts must be reattached within a few hours of amputation. Parts that contain large amounts of muscle must be reattached within 6 hours. Those that do not contain muscle may last up to 12 hours.
It is important to understand that aside from ensuring that the detached part is reattached within the prescribed time limits, it is also imperative that the part is preserved as best as possible. The amputated part must be placed in a sterile container at temperatures close to freezing. The temperature must not reach or exceed freezing levels.
One way to accomplish this is to place the part in a bag or container with water and ice. Dry ice cannot be used as it could destroy nerves, tissue, and blood vessels.
If possible, every part of the amputated limb or digit must be retrieved, even though it may not seem to be salvageable. It will be up to the surgeon to decide which parts can still be used.
The physical and mental condition of the patient will also determine whether the procedure will be successful or not. For instance, patients with medical conditions that prevent them from being under the influence of an anaesthetic for prolonged periods are not good candidates for a replantation procedure. Those with medical conditions, such as hypertension, diabetes, or vascular disorders are likewise not good candidates.
Additionally, those with a psychological condition may have a problem recuperating, thus would also not be considered for the procedure.
Who Should Undergo & Expected Results
People of any age may undergo the procedure. However, studies show that children have a better response. In fact, almost any part of a child’s body may be replanted if it meets certain conditions. Anybody who has undergone trauma resulting in an amputation of the forearm, hand, or digit should attempt to undergo a replantation procedure regardless of the condition of the amputated part. Those that have lost a thumb or multiple digits, a part of their hand, the entire hand from the wrist, or the forearm are good candidates for the procedure as long as the amputated part is still in a good condition.
However, it is important to note that undergoing a replantation procedure does not necessarily mean that it will be successful. There is still a possibility that the procedure may result in a total or partial failure. A total failure indicates that the attached portion did not survive after the procedure. A partial failure would mean that the attached part only regains 50% of its motion, or lower.
If the procedure is successful, the patient should regain almost 100% of the replanted part’s motions.
How Does the Procedure Work?
The replantation of the forearm, hand, and/or digits involves reattaching the nerves and tiny blood vessels. To increase the chances of a successful procedure, surgeons will need to perform microsurgery.
Prior to the procedure, doctors will need to ensure that the separated part has been cleaned thoroughly and kept in a sterile environment. The procedure will then take place in a certain sequence.
- First the surgeon will reattach the bone/s.
- Next will be the repair of the extensor tendon.
- The arteries will follow and then the veins.
- The last three parts will be the flexor tendon, nerve, and skin. In some cases, flap surgery may be needed to cover the area if skin has been severely damaged.
- If multiple fingers of the hand have been amputated, the surgeon will first repair the thumb, then the long finger, the small finger, and lastly the index finger.
After the procedure, the patient will be closely monitored so that any problems can be identified and promptly addressed. The environmental temperature will be key in the success of the procedure. The patient needs to be kept in a warm room, or one with an 80 degree Fahrenheit temperature. Even the patient’s skin temperature will be closely monitored as changes over 2 degrees will indicate a problem.
Possible Risks and Complications
As mentioned earlier, there is a possibility that the procedure may end up in a failure. Aside from this, there are also possibilities of complications developing. Some complications are myonecrosis, myoglobinuria, infections, and intolerance to cold environments.
When it comes to regaining normal function of the amputated limb or digit, age will play a factor. This is particularly true for older patients with zone 2 amputations. Zone 2 refers to amputations that occur anywhere between the upper portion of the palm to the middle portion of the fingers.
Digit Replantation / Upper Extremity Reconstruction; Duke Orthopaedics; http://www.wheelessonline.com/ortho/digitreplantationupperextremityreconstruction
Harvey Chim, MD, Marco A. Maricevich, MD, Brian T. Carlsen, MD, Steven L. Moran, MD,Christopher J. Salgado, MD, Fu-Chan Wei, MD, Samir Mardini, MD; “Challenges in Replantation of Complex Amputations”; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3842345/