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Amputation of the Hand

Amputation of the Hand

On Tuesday, 13 October 2015, 85 year-old Mdm Khoo had her hand amputated in a lift accident in Tah Ching Road. In this article, our Hand and Microsurgery specialist, Dr Winston Chew shares on the Types of amputation and Reattachment options to give a better understanding of this type of devastating injuries.

What is Amputation of the Hand?

Amputation is a type of injury in which the hand is severed. This results in cutting off the blood supply to the hand, resulting in death of the tissues after several hours. It also results in loss of function as the bones are broken, the muscles or tendons are disconnected and hence cannot control movements in the hand, and the nerves are disrupted so they cannot perform the function of transmitting sensation or control the movements of the muscles. Complete amputation is when the part is completely detached from the body. Incomplete amputation is when certain parts may still be attached. In the case of Mdm Khoo, it was a complete amputation.

What are the Types of Amputation?  

Amputation can be categorized into Major and Minor amputation.

When the amputated part contains significant muscle tissues (hand, forearm, or arm), it is considered a Major amputation. The importance of the presence of muscles is that muscles cannot withstand loss of blood supply for more than 4-6 hours. After which, muscle tissue will start to die making reattachment not possible. This muscle survival can be prolonged by cooling the amputated hand with ice. The higher the level of amputation in the arm, the worse the function after eventual recovery. The best outcome for a major amputation is for those at the level of the wrist.

Minor amputations are so called when it involves the fingers. As they do not contain muscles, the fingers can survive for a longer period of time. Typically, it can survive beyond 12 hours, especially when cooled.

In the case of Mdm Khoo, it is likely to be an extensive crush if the hand was severed by the lift door, or an avulsion type if the hand was pulled off by the leash of the dog caught in the lift door. In either case, the damage would be expected to be severe. It is considered a major amputation, as the hand contains significant amount of muscle.

extensive-crush-avulsion

Diagrams show possible amputation mechanisms for Mdm Khoo’s injuries.

How can one render First aid?  

1.  Remove victim from danger (if possible)

2.  Stop the bleeding: Apply pressure on wound using a clean cloth or compression bandage. Elevate the arm to stop bleeding.

3.  Preserve the amputated part: Rinse part with clean water and put it into a clean plastic bag, then into another plastic bag with ice. Cooling prolongs survival of amputated part while double plastic bag prevents soaking severed part in water.

What are the Procedure risks?

In general, doctors will try to reattach all major limb amputation, such as that of the hand. The reason is that current technology is not able to recreate a hand substitute. As reattachment is a complex and long surgery, there are important factors to consider:

  • Patient factors

Medical conditions such as diabetes, hypertension and heart conditions increase the risk of complications. Risk also increases with age of the patient.

  • Extent of damage

The more severe the injury, the lower the success of replantation. The higher the amputation level, the worse the function after surgery.

  • Timing

A delay of more than 6 hours makes reattachment less feasible due to multi-organ failure. When muscle tissue dies, the wound may result in infection.

  • Surgeon and Surgery Facility

In Singapore, most hospitals are equipped with the capability to perform reattachment surgery.

In the case of Mdm Khoo, at 85 years of age, she is at higher risk for such a surgery. As mentioned above, Mdm Khoo’s injury may most likely be the extensive crush or the avulsion type, which are less likely to be replantable.

What is the outcome of Hand Replantation?

The best recovery of hand replantation (reattachment) is at the level of the wrist. The higher the amputation level, the worse the function. Nerve regeneration is a major limiting factor as most of the functions require the nerve to work well.

The younger the child, the better the recovery. This is because nerve regeneration in the young is good, and recovery is much better, especially for those below 10 years of age.

In general, it has been found that a replanted hand can function better than an artificial hand (prosthesis). But a long period of therapy is required before recovery, which may take up to a year or more, depending on the level. Follow-up surgery often need to be done, the average being about 3 additional procedures after the replantation surgery.

Written by Dr Winston Chew Yoon Chong, Hand & General Orthopaedic surgeon

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