Leeds has had a pioneering role in reconstruction of digits in children using microsurgical transfer of digits from the foot. This does not mean that we are ignorant of or blind to the other options for treatment in congenital or traumatic absence of digits (including the option of doing nothing, distraction lengthening, or bone transfer) and all of these options are available and will be discussed with parents.
The absence of a finger does not usually have much effect on either the function or the appearance of the hand. When the digit that is missing is a thumb, or when many digits are missing, surgery may be needed. Generally the guideline in considering reconstruction is whether or not the overall function of the hand may be improved, although it is also natural and necessary to take into consideration the appearance of the hand.
Transplantation of one or more toes, or parts of toes, is one method of reconstruction. There are advantages and drawbacks to this technique, and a full understanding is important for the family to make sensible decisions about surgery.
The most commonly transplanted toe is the second toe, since it is the longest toe and combines all the useful characteristics of a digit (such as joints, a nail, sensitive pulp tissue, and the ability to grow) with a good reliable blood supply. After the toe has been transferred, the foot is repaired by closing the gap between the third and the big toe. There will always be a scar on the foot. One second toe may be taken from each foot with surprisingly little effect on the function or appearance of the foot. When more than one toe is taken the cosmetic effect on the foot is considerable, and so I am reluctant to do this. This therefore limits the number of digits that can be reconstructed in the hand using this technique to a maximum of two.
Following toe transfer, there is no reason to expect problems with walking or athletic pursuits, nor is there any reason to suppose the child will be more prone to problems with bunions in the long term.
Rarely is the big toe used as a transplant for the hand, since it leaves a far more noticeable defect on the foot. Occasionally in exceptional circumstances it is appropriate to use this toe, either because the patient has no other toes, or because the greater bulk that it offers in the hand is felt to be advantageous. Sometimes a partial great toe transfer (known as a wrap around flap or WAF) is recommended. Here only the nail and the pulp of the toe are used, and the main structure of the toe is left in place, the transplanted skin and nail being replaced by skin grafts. This transplant has the benefit of making an excellent thumb where only part of the thumb needs to be replaced, and yet preserving most of the great toe and its function in the foot. In any case, when the great toe is transferred as a whole, the loss of function in the foot is surprisingly slight.
Whichever toe is transferred, its blood vessels (artery and nerve) must be successfully joined to similar vessels in the hand for it to survive. This intricate part of the operation is performed under the operating microscope (and so the operations is known as microsurgical toe to hand transfer) and is usually straightforward. Occasionally these vital vessels do not carry enough blood for the survival of the toe, and the transfer fails. This is very rare (probably occurring in less than 5% of cases) but leads to total failure of the transplant which is effectively "rejected".
Tendons (to allow movement where required), nerves (to allow feeling), and the bone must also be rejoined to suitable counterparts in the hand. In the case of the bone this is usually held together whilst it heals with fine pins (known as K wires) which may be left poking out through the skin. These will usually be withdrawn between three and six weeks after the initial operation, and in some cases we give a brief general anaesthetic for the purpose.
The longer term post-operative care of such transplants is described in a separate information sheet.
Following microsurgical transplantation of a toe to the hand the whole arm is immobilised in a dressing which includes a plaster of paris splint. This will usually be left undisturbed for two or three weeks before the first change of dressing.
The first change of dressing will be performed either under a brief anaesthetic in theatre, or on the ward if only simple removal of the dressing is required. Usually stitches will be absorbable and do not require removal, whilst the pins used to fix the bones may be removed without an anaesthetic. One advantage of changing the first dressing under anaesthetic is to make a splint to protect the new digit in the coming months. This is more easily made with the child still and serves a number of purposes. It splints the bones together until they unite, and protects the new digit from injury including being bitten! This is not as bizarre as it may sound, since at first the new digit has no feeling and the child will not feel pain when biting it.
Gradually the feeling returns as the nerves that have been rejoined grow into the digit, and at first the sensation the child will experience may be mildly unpleasant, much like the pins-and-needles sensation you feel if your arm has "gone to sleep" and then its feeling returns. You can help to shorten this period by gently but firmly massaging and cleaning the digit, and getting the child used to having it touched. The surgeon and the therapist will explain this more fully.
Usually the return of feeling takes about twelve weeks, and thereafter the splint may be worn less and less. Specific instructions will be given to each parent on this topic since occasionally other reasons for splinting may arise, such as the need to correct a deformity or protect a repaired tendon.
You may be asked to help your child further by gently stretching and working the joints as they recover, and again the hand therapist will explain this in greater detail as the need arises. For at least the first year after surgery, the transferred part will feel the cold more than the other fingers, and will need to be kept warm in cold weather.
Sometimes there is a need for "secondary surgery" to correct some problem with the transferred digit. This may be planned from the outset and part of a staged treatment plan (for example, when muscles are later rearranged to allow greater range of movement in the digit) or may be unexpected (if a tendon becomes stuck and requires freeing to improve the movement of a joint). This surgery is usually relatively minor for the child and should not be a cause for anxiety, with only a short period in hospital. Two particularly common reasons for secondary surgery are the adjustment of scars and the adjustment of bones.
Often we do not stitch a wound up tightly at the first operation (since the microscopic blood vessels are peculiarly sensitive to pressure) but allow it to heal with a skin graft (see separate information sheet). This may leave a rather less satisfactory scar that may be removed at a later date in a minor procedure.
Usually we obtain healing of bones in exactly the position we want them, but like all "fractures" the junction of the toe and the hand bones may heal slightly out of position. This is not usually a problem but occasionally it is necessary to undertake a small procedure to revise the position.
You will have regular follow-up appointments at the clinic in order to ensure that this aftercare goes smoothly.
Professor Simon Kay, Consultant Plastic Surgeon
Plastic and Reconstructive Surgery including: