Definition & Overview
Replantation surgery is a complex, technically demanding surgical operation in which an amputated body part, most commonly a finger, hand, or arm, is reattached to the body. Due to various advancements in techniques used as well as in available technologies, the procedure is now also used to reattach toes, feet, legs, ears, lips, tongue, and even the genitals. The surgery has been in use since 1962 and to date, thousands of patients have had severed body parts reattached, preventing the loss of hand or arm function due to amputations.
Replantation surgery, which main goal is to retain the function of the amputated body part, can be quite complex as it involves repairing and reconnecting the affected blood vessels, nerves, and tendons.
Who Should Undergo and Expected Results
Replantation surgery is for individuals who suffer from amputations or ischaemic injury, often due to accidental trauma.
The procedure can reattach not only large body parts but also smaller ones, such as fingers and toes, thanks to the development of the operating microscope, which magnifies the microscopic blood vessels and nerves of these small body parts that makes microvascular replantation possible.
The most common body parts that are typically replanted include the fingers, hands, and arms. However, the procedure can also be performed on toes, feet, legs, ears, lips, tongue, and even the penis. The decision to put a patient through the complex procedure is influenced by the following factors:
- The importance of the severed body part
- The severity of the injury
- If the restoration of function of the affected body part can be expected
- The mechanism of the injury
The goal of a replantation surgery is to reattach the severed body part while ensuring that its function is restored to normal. To do so, the muscles, tendons, arteries, and veins have to be repaired as well. Since 100% restoration of function is rare and almost impossible, 60% to 80% restoration is considered by a success by surgeons.
To ensure successful replantation, the surgery must be performed as soon as possible following the amputation. While waiting for surgery, the severed body part should be properly preserved, preferably in a sterile, cool but not freezing environment. It should also be placed in a clean or sterile container filled with ice water or wrapped in moist gauze. All severed parts, including those that do not seem usable, should also be preserved, as surgeons will need all available pieces of human tissue during the procedure.
The length of time during which a severed body part can be stored and preserved varies depending on the affected body part. Fingers can be generally preserved after several hours from the time they were detached from the body; the same is true for all other body parts that do not have major muscles. On the other hand, body parts with major muscles, such as arms and legs, have to be replanted within 6 to 8 hours to ensure the viability of the limb.
How is the Procedure Performed?
The procedure to replant amputated body parts generally follows the same process. First, patients are placed under regional or general anaesthesia (depending on the severity of the injury) before all damaged tissue at the stump is carefully removed. The ends of the bone are then shortened and rejoined using pins, plates, and screws. Once the parts of the affected bone are reconnected, the surgeon begins to work on the muscles, tendons, arteries, nerves, and veins.
In some cases, a grafting procedure may also be required to replace affected or missing bone, skin, tendons, and blood vessels to complete the surgery. Most grafts are taken from other parts of the patient’s body to increase chances of success and to reduce the risk of adverse reactions. However, if this is not possible, the grafts can also be taken from a tissue bank.
Regaining the function of the replanted body part generally depends on the re-growth of sensory and motor nerves, which tend to grow an inch per month. Thus, the length between the tip of a limb to the replantation site provides a clue as to how long it will take for the patient to start feeling sensations all throughout the replanted body part.
The success of the procedure depends on several key factors, including:
- The patient’s age – Younger patients have a higher chance of restoring the full function of the replanted body part.
- Area of injury – The further down the replanted part of the arm is, the greater the chances of its full function returning.
- Non-joint injury – If a joint is not injured, the patient is more likely to regain full movement.
- Extent of injury – If the body part is cleanly severed, the patient’s chances of regaining better function is higher than when the body part is crushed or pulled off.
- Temperature – Cold temperatures can increase a patient’s discomfort during the recovery process.
- Smoking – This can delay recovery or prevent full restoration of function as it can inhibit proper blood flow to the replanted part.
During the recovery process, patients are advised to keep the replanted part just above the level of the heart to increase circulation.
In the case of major limbs, such as arms and legs, patients may need to undergo physical therapy as well as bracing during the recovery process. Bracing can help protect the repaired tendons and muscles during recovery, while therapy helps prevent stiffness and scar tissue formation. It also encourages blood circulation and keeps the muscles mobile.
Possible Risks and Complications
The following are the risks and complications associated with replantation surgeries:
- Muscle or tissue death
- Shorter limb
- Allergic reactions to medications or anaesthetics used
- Reduced nerve function or movement
- Stiffening of the fingers or limbs
- Residual pain
The success of a replantation procedure can be predicted by checking the potassium level of the blood that flows out of the replanted part after surgery and revascularisation. If there is a high level of potassium, this may indicate a high risk of muscle or tissue death.
In cases of severe crush injuries wherein the tissues are jagged at the edges, the surgeon will need to perform a revision amputation on the stump. This will cause the limb, when reattached, to be slightly shorter than it used to be.
Friedrich JB, Poppler LH, Mack CD, Rivara FP, Levin LS, Klein MB. “Epidemiology of upper extremity replantation surgery in the United States.” J Hand Surg Am. 2011 Nov; 36(11):1835-40. http://www.ncbi.nlm.nih.gov/pubmed/21975098
Maricevich M, Carlsen B, Mardini S, Moran S. “Upper extremity and digital replantation.” Hand (NY). 2011 Dec;6(4):356-363. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3213257/