Indications for replantation

Current consensus generally accepts that replantation is indicated for the thumb, single digits distal to superficialis insertion (mid middle phalanx), multiple digits, and all amputations in children [24,25]. Looked at another way, the only nonreplantable indication is for single digits at or proximal to the proximal interphalangeal joint in adults. Even this is relative because now patients' demands will override wisdom and explanation. The results of replantation obviously depend on the nature of the original injury and the judgment that determined the decision to replant but are particularly related to the detail of the surgery itself. The decision to replant and the outcome of that decision have significant consequences for the patient, the hospital, and the public purse.

The overriding question when confronted with an amputation should be, ''from my knowledge of hand surgery, fractures, tendon, and nerve repairs, what is the realistic potential for this digit to contribute to function, or might it not only be functionless but even worse, interfere with the remaining hand function?'' In making this judgment, it is implied that the surgeon knows the function of each digit and at each level and what the disability will be if the part is not reattached. By definition, the novice resident alone in the emergency trenches at 3 am will not be struck with enlightenment. In fairness to patient, resident, and public purse, amputations should be evaluated by an experienced surgeon. In general terms, the radial three digits are concerned with pulp pinch grip and work as a team. Therefore, sensibility excellence is of greater importance than mobility. Sensory return in replanted digits is normally more reliable than is restoration of movement. Amputations of the distal portion of the index and middle fingers in combination pose a strong indication for replantation to restore pulp pinch. Replantation of the proximal index finger alone in a single injury, however, would be contraindi-cated as the sensory return would rarely approximate that of the middle finger, which would always be substituted in its place. If the radial digital nerve remained intact, it would demand a rethink. Conversely, for ulnar-sided digits, which are primarily for palmar grip function independent of the thumb, sensibility is of less importance than the mobility. Proximal amputations of the little finger alone would be most unlikely to be beneficial knowing the limitation of range of movement that is achieved, but if the flexor tendon is still intact, it would become a much more favorable indication. Replantation of distal amputations of the ring and little finger combined could be strongly argued because of the need for digit length to allow full closure of the terminal phalanges into the palm. Even stiff distal interpha-langeal joints will allow good grip function, provided the digits have adequate length.

An algorithmic audit assessment of bone, joint, tendon, nerves, and skin should be considered. Shattered missing bone will usually lead to difficult fixation, prolonged immobilization, poor tendon gliding, tendon length imbalance, and the risk of nonunion. Joint destruction leads to stiffness, and stiffness of the ulnar digits will greatly compromise function, because their role is to fold into the palm for palmar grip. Radial fingers and the thumb require sensation and can compensate for stiffness more readily. The metacarpophalangeal joint of the fingers is key to flexion grip, and if this is stiff, then replantation is likely to be a hindrance to adjacent finger function. The extensor tendon is the most complex structure in the digit in terms of its delicacy of gliding linkage mechanisms, and repairs over the proximal phalangeal region along with shattered underlying bone and periosteum are unlikely to glide or transmit extensor function to the distal joints. Thus, two distal joints may now be stiff from an injury that did not directly involve either. Significant nerve loss or avulsions have no chance of sensory recovery.

Single digit amputations distal to the super-ficialis insertion (mid middle phalanx) were originally considered poor indications but are now accepted to be one of the better indications for replantation because even though the distal joint may not function well, provided the nerves can be joined, the restored length will ensure reasonable automatic function (Fig. 1). Replantation at this level is relatively straightforward technically, and patients do not require prolonged rehabilitation or time from work.

Fingertip replantations once thought frivolous are now seen as the ideal flap repair and simply require anastomosis of an artery and a vein. The alternative is local flap repair that will further damage the digit. The best flap repair is with the tissue that has been lost, and the time for healing should be the same or less than for a local flap.

Fig. 1. (A) Guillotine amputation distal ulnar digits. (B) Amputated parts. (C) Postoperative result at 3 months. The middle finger replant is an artery-only replant. (D) Grasp function is maintained with restoration of length in the replanted digits.

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