1. What is replantation?
2. Traumatic amputations can be broadly divided into 3 types :
3. Are all amputated digits and limbs suitable for replantation?
4. What is the ischemic time?
5. How should the amputated digit or limb be managed?
6. How will the amputated part be reattached?
7. What are the common risks of replantation?
8. How long will the patient stay in hospital after replantation?
9. What will be the option if replantation is not indicated?
10. What are the expected outcomes after replantation?
Replantation of digits and limbs is the surgery to reattach the completely amputated digits and limbs.
Crushing type is usually caused by machine. Due to direct crush; soft tissue injury around the wound is common
Avulsing type is also usually caused by machine. The digit or limb were trapped by the machine or there is rotating force on the entrapped limb; and the victim try to withdraw the limb forcefully and results in avulsion injury. The nerves, vessels and tendons are usually torn badly
Guillotine type is caused by sharp cutting object, e.g. choppers in assault, domestic or industrial injuries. The wound edge is sharp and neat
The indication for replantation depends on many factors such as the site of injury, the number of injured site, the type of injury, the interval between amputation and time of replantation (ischaemic time), the age, and the general condition of the patient.
The following are some of the favourable criteria for replantation :
Amputation of thumb, multiple digits, forearm and arm
Child and young age
Guillotine–type of amputation e.g. clean cut with minimal damage to the vessels and nerve
Replantation is not recommended in cases of severely crushed or avulsed amputated part, amputation at multiple levels, prolonged warm ischaemic time and poor general health of the patient.
In warm environment e.g. room temperature, the tissue of an amputated digit will usually be ‘rotten’ in 12 hours(warm ischaemic time). If replantation is performed more than 12 hours after the injury, the chance of success will be much decreased.
If the amputated part is kept at 4˚C, the tissue of the amputated part may survive up to 24 hours(cold ischaemic time).
If the amputated part contains muscle, the acceptable warm ischaemic time for replantation will be shorter e.g. 6 hours because muscle undergoes necrosis easily. The acceptable cold ischaemic time is about 12 hours.
In order to minimize necrosis of the amputated part, it should be kept ‘cold’. The amputated part should be wrapped in a moist gauze or towel and placed in a clean plastic bag. The plastic bag is then put into a second plastic bag containing ice cubes and small amount of water to keep the temperature at around 4˚C. The amputated part should be brought to the hospital with the patient as soon as possible.
Under general or regional anaesthesia, the bone needed to be adequately shortened in order to decrease the tension over the repaired vessels and nerve and the bones were stabilized with wire or plate. The cut tendons are repaired next. Then, the artery, veins and nerves are repaired in order. For digits, the vessel and nerve repair are performed under microscope magnification. The skin is then sutured.
Bleeding, infection, failure of replantation, death of the replanted tissue, joint stiffness, residual pain and reduced sensation are common complications after replantation surgery. Moreover, there are risks associated with general or regional anaesthesia.
In general, if no complication arises, patients with replantation of digits will stay in hospital for a few days to monitor the blood flow to the replanted part. The replanted limb is kept warm. The blood pressure and urine output are monitored. Sometimes, infusion of drug may be needed to maintain the blood flow to the replanted part.
If replantation is not suitable, revision amputation’ will be the option. The exposed bone end is trimmed and smoothened, and the exposed nerves are cut short to prevent formation of painful neuroma. The skin is then closed.
The rehabilitation period for revision amputation is much shorter than replantation.
In general, children and patients with distal amputations have better outcome. Satisfactory recovery of the nerve function is likely. The functional result is expected to be good in thumb replantation.
Dr. SIU, Kwai-ming