Microsurgery means repairing vessels and nerves one or two millimetres across under a microscope. It makes it possible to reconnect amputated parts and to move tissue from one area of the body to another.
The urgent part first, because it is what changes the outcome. For an amputated finger or segment: cover the wound with a clean cloth and press to stop the bleeding, wrap the amputated part in gauze moistened with saline, put it in a sealed plastic bag and place that bag on ice — never the segment in direct contact with ice and never submerged in water, because that damages it irreversibly — and go immediately to a hospital with microsurgical capability. A finger properly kept cold can be replanted many hours later; badly kept, it is lost within a few.
Microsurgery is a technique that cuts across specialities: it is used in replantation, but also in repairing nerves in the hand, in transferring tissue with its own vessels to reconstruct a defect and in lymphoedema surgery. What they all share is the scale: the work is done under a microscope, with sutures finer than a hair, and the first days of monitoring afterwards are as decisive as the surgery itself. A replantation in particular demands a trained team, a theatre available urgently and several days in hospital.
It usually helps when there is
- Traumatic amputation of a finger, a hand or a segment, with urgent transfer.
- Division of nerves requiring repair under the microscope.
- A defect that can only be covered with a free tissue transfer.
- The consequences of an old nerve injury that can be reconstructed with a nerve graft.
- Lymphoedema amenable to microsurgical treatment.
Worth discussing first if
- Amputation by crushing or severe avulsion, with lower viability.
- A badly preserved segment or too many hours of ischaemia.
- General health that will not tolerate many hours of surgery.
- Current smoking, which significantly compromises the result.
- Cases where a well-fashioned amputation gives better function than a stiff replanted part.
None of these rules the procedure out on its own; all of them change the conversation.
Where it is used
Different situations sharing the same underlying technique.
Replantation
Reconnecting an amputated segment: bone, tendons, arteries, veins and nerves. It is an emergency and its viability depends on the hours elapsed.
Nerve repair
Direct suture or nerve graft under the microscope. Recovery of sensation is slow and progressive, in the order of a millimetre a day.
Free transfers
Tissue detached from one area and reconnected in another to the recipient vessels. It resolves defects no other technique covers.
Not everything replantable should be replanted
It is the hardest decision in this surgery. There are amputations where replanting is clearly the right choice: the thumb, several fingers at once, the whole hand, and practically any amputation in a child. And there are others where a technically possible replantation leaves a stiff, numb, painful finger that gets in the way more than its absence would, while a well-fashioned amputation allows a functional hand within a few weeks. It is decided case by case, with the patient informed.
Ischaemia time governs everything. A segment with no muscle, such as a finger, tolerates many hours if it is correctly kept cold; a segment with muscle bulk, such as a forearm, tolerates very few, because ischaemic muscle releases substances that can put the patient's life at risk when the circulation is restored. That is why keeping it cold is not a detail.
After the surgery, monitoring is everything. For the first three to five days the colour, temperature and capillary refill are checked continuously: thrombosis of the repaired vessel can be resolved if it is picked up early and reoperated, and is lost if it is picked up late. Cold, nicotine and caffeine are avoided because they constrict the vessels.
What the process is like
In a replantation, it all starts at the scene of the accident.
First aid
Press to stop the bleeding, wrap the segment in gauze moistened with saline, put it in a sealed bag and place the bag on ice. Urgent transfer.
Assessment
The viability of the segment, the mechanism of injury and the state of the patient are assessed, and the choice between replanting and formalising the amputation is made.
Surgery
Under the microscope and lasting several hours. The bone is fixed, tendons, arteries, veins and nerves repaired and the skin covered.
Monitoring and rehabilitation
Days of close monitoring of the circulation as an inpatient, and then months of hand therapy to recover movement and sensation.
What to expect
It is among the longest recoveries in the catalogue.
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Days 1 to 7
Hospital stay with continuous monitoring of the circulation of the segment. A warm environment, no nicotine or caffeine, the limb rested and elevated.
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Weeks 2 to 6
Dressings and monitoring of bone healing. Protected movement with a hand therapist begins.
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Months 2 to 6
Intensive rehabilitation. Movement recovers progressively. Sensation starts to advance along the repaired nerve.
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Months 6 to 24
Final functional result. There may be secondary operations on tendon, bone or to release adhesions.
Risks, and what is not promised
The main risk is thrombosis of the repaired artery or vein, which may force an urgent reoperation and, if it is not resolved, the loss of the replanted segment or the flap. Infection, failure of the bone to heal, joint stiffness, incomplete recovery of sensation, cold intolerance — very frequent and persistent after a replantation — and neuropathic pain are also possible.
It is long surgery, with its own anaesthetic risk, and it frequently requires secondary operations months later to improve function. Smoking is the modifiable factor that weighs most: nicotine constricts the small vessels and directly compromises what has just been repaired.
It is not promised that a replanted segment will work as it did before: partial movement and sensation are the norm, and in many cases the hand ends up functional but different. Nor is it promised that replantation is always the best option; sometimes a well-fashioned amputation gives better function. These risks are reduced by correct preservation of the segment, urgent transfer, strict monitoring and giving up smoking. They are not eliminated. The ones that apply to your case are set down in writing in the informed consent.
The information on this page is for guidance and does not replace an in-person medical consultation. Medical practice is an obligation of means, not of result.
The questions we are asked most about replantation and microsurgery
Wrap it in gauze or a clean cloth moistened with saline, put it in a well-sealed plastic bag and place that bag on ice. Press the patient's wound with a clean cloth and go immediately to the emergency department.
Very important: the segment must never touch the ice directly or be submerged in water or alcohol. That damages it irreversibly and makes replantation impossible.
It depends on the segment. A finger, which has no muscle bulk, can tolerate many hours if it is properly kept cold. A forearm or a hand, with muscle, tolerates very few.
In any case, the sooner the better: transfer must be immediate, without waiting for the swelling to go down or for an appointment.
No. There are cases where a technically possible replantation leaves a stiff, numb, painful finger that gets in the way more than its absence would.
In the thumb, in amputations of several fingers, in the whole hand and in children, the indication is clear. In a single finger of the non-dominant hand with a crush injury, the decision is discussed with the patient.
Cold intolerance is very frequent after a replantation or a nerve repair: the area hurts or goes stiff in low temperatures.
It improves over the first two years but often does not disappear completely. It is one of the things worth knowing before deciding.
Question not answered here? There are more answers in the frequently asked questions.
