Replantation

What is replantation?

Replantation is the medical term for reattachment of a completely severed body part. In hand surgery this is most commonly a finger or thumb, although replantations of the hand, forearm, arm and other body parts are possible.

Is replantation always possible?

Replantation is not always possible. Sometimes the severed part is too badly crushed or damaged to reattach. Sometimes a surgeon will advise against replantation, particularly if she or he believes that the reattached part will never gain proper movement or adequate sensation. If a patient is extremely unwell, or if it has been too long since the injury it might not be feasible to perform replantation.

Sometimes, despite the rapid and best efforts of everyone involved, replantation surgery is unsuccessful. Successful replantation surgery depends on delicate microsurgical techniques, where tiny blood vessels are stitched together by hand under a microscope. Some factors make it more likely that microsurgery will fail (such as smoking, poor condition of the blood vessels, significant crush injury, long standing diabetes). These factors may be considered contraindications to replantation - that is, reasons to recommend against replantation in a particular patient. That said, microsurgery has high success rates and can have great outcomes. 

What is the difference between a replantation and a transplantation?

For the surgeon there is no major technical difference between a replantation and a transplantation. Both involve microsurgical techniques where one body part is reattached to another body part.

In transplantation, however, the body part that is being attached comes from another person. This is why transplant recipients need to take medications to reduce the likelihood that their body will reject the reattached part - unless it comes from their identical twin. In replantation there is no danger that the body will reject the reattached part, but it is possible that technical factors (like the artery blocking off) may lead to the replantation failing.

What is the immediate first aid treatment for amputation of a finger or limb?

First aid should be applied both to the affected person and to the amputated part. The primary goal is to ensure the survival of the person! An amputation is an emergency so call 000 and request an ambulance.

An amputated part needs to be treated carefully to maximise the chances at successful replantation surgery. How you can do this depends on what resources you have to hand. Ideally the part needs to be kept cool (but not frozen), clean and slightly moist. If you do not have plastic wrap, saline, cloth or ice simply wrap the part in whatever you do have (a piece of paper, a handkerchief, etc) and give the part to the ambulance officer, clearly stating what it is.

If you do have a first aid kit or adequate resources around, the part should be wrapped in saline-moistened gauze, placed in a zip-lock plastic bag with air in it, and that bag placed in an ice slurry (a container that has ice and some water in it).

Do:

• gently remove mud, grass or dirt by running under clean water for 5-10 seconds
• wrap the part in moistened gauze (or a handkerchief, or a piece of cloth)
• wrap the part in clean cling-wrap or plastic
• transport the part with the patient to the nearest hospital

Don't: 

• soak the part in water, or allow it to become waterlogged
• allow the part to dry out
• allow the part to lie directly on ice, as it will freeze (freezing is bad)
• rub, crush or otherwise injure the part

The purpose of the ice is to keep the amputated part cool at 1-4 degrees celsius. This reduces the metabolism of the tissue, allowing it to remain viable for longer. Ideally replantation surgery is commenced within 6 hours of the amputation, and the quicker the better.

How is replantation surgery performed?

Any damaged tissue is cleaned from the amputated part and from the injured body part. The bone ends are rejoined either using wires or screws. Tendons and muscles are repaired, as are arteries, veins and nerves.

If the replantation is successful blood flows within the arteries and veins immediately, and continues flowing. Sometimes skin grafts are required to cover any areas where there is missing skin from the injury.

What happens after replantation surgery?

After the replantation surgery the reattached body part is monitored very closely for a number of days to ensure that adequate circulation (both arterial and venous) is maintained. Sometimes a replanted part will get congested with blood because the venous blood flow is inadequate. In such instances leeching may be used temporarily to maintain adequate blood flow (either chemical leeching, or physical leeching - with real medical leeches).

It is common for a patient to remain in hospital for 4-7 days after successful replantation surgery, to monitor the surgery and provide specialist care that will reduce the likelihood of failure of the surgery due to clots in the blood vessels. Often a blood thinner such as heparin, clexane or aspirin (or a combination of these) is prescribed to help thin the blood and reduce the likelihood of clots. Antibiotics are also prescribed to reduce the risk of infection.

What is the recovery period?

The recovery period varies widely depending on the type of amputation. Blood flow to the affected part is restored immediately. Sensation in the affected part takes much longer to regain, as an injured nerve must grow (at a rate of 1mm a day) from the injury site to the tip of the finger before sensation recurs.

The recovery of fractures takes 6 weeks and tendon injuries take approximately 6-12 weeks. It is common for there to be scarring that limits the range of motion of the repaired tendons. Return to work after replantation is usually slow (ie 3 months or more) and the long recovery time is sometimes a factor in the decision about whether to try replantation surgery or to opt not to have the digit replanted.